Gene-expression assays to tailor adjuvant endocrine therapy for HR+/HER2- breast cancer

Adjuvant endocrine therapy represents the standard of care for almost all HR+/HER2- breast cancers and different agents and durations are currently available. In this context, the tailoring and optimization of adjuvant endocrine treatment by reducing unnecessary toxic treatment while taking into account the biological heterogeneity of HR+/HER2- breast cancer represents a clinical priority. There is therefore a significant need for the integration of biological biomarkers in the choice of adjuvant endocrine therapy beyond currently used clinicopathological characteristics. Several gene-expression assays have been developed to identify patients with HR+/HER2- breast cancer who will not derive benefit from the addition of adjuvant chemotherapy. By enhancing risk stratification and predicting therapeutic response, genomic assays have also shown to be a promising tool for optimizing endocrine treatment decision. We here review evidence supporting the use of most common commercially available gene-expression assays (Oncotype DX, MammaPrint, Breast Cancer Index, Prosigna and EndoPredict) in tailoring adjuvant endocrine therapy. Available data on the use of genomic tests to inform extended adjuvant treatment choice based on the risk of late relapse and on the estimated benefit of a prolonged endocrine therapy are discussed. Moreover, preliminary evidence regarding the use of genomic assays to inform de-escalation of endocrine treatment, such as shorter durations or omission, for low risk patients are reviewed. Overall, gene expression assays are emerging as potential tools to further personalize adjuvant treatment for patients with HR+/HER2- breast cancers.

Tumor-Infiltrating Lymphocytes in Triple-Negative Breast Cancer

Importance

The association of tumor-infiltrating lymphocyte (TIL) abundance in breast cancer tissue with cancer recurrence and death in patients with early-stage triple-negative breast cancer (TNBC) who are not treated with adjuvant or neoadjuvant chemotherapy is unclear.

Objective

To study the association of TIL abundance in breast cancer tissue with survival among patients with early-stage TNBC who were treated with locoregional therapy but no chemotherapy.

Design, Setting, and Participants

Retrospective pooled analysis of individual patient-level data from 13 participating centers in North America (Rochester, Minnesota; Vancouver, British Columbia, Canada), Europe (Paris, Lyon, and Villejuif, France; Amsterdam and Rotterdam, the Netherlands; Milan, Padova, and Genova, Italy; Gothenburg, Sweden), and Asia (Tokyo, Japan; Seoul, Korea), including 1966 participants diagnosed with TNBC between 1979 and 2017 (with follow-up until September 27, 2021) who received treatment with surgery with or without radiotherapy but no adjuvant or neoadjuvant chemotherapy.

Exposure

TIL abundance in breast tissue from resected primary tumors.

Main Outcomes and Measures

The primary outcome was invasive disease-free survival [iDFS]. Secondary outcomes were recurrence-free survival [RFS], survival free of distant recurrence [distant RFS, DRFS], and overall survival. Associations were assessed using a multivariable Cox model stratified by participating center.

Results

This study included 1966 patients with TNBC (median age, 56 years [IQR, 39-71]; 55% had stage I TNBC). The median TIL level was 15% (IQR, 5%-40%). Four-hundred seventeen (21%) had a TIL level of 50% or more (median age, 41 years [IQR, 36-63]), and 1300 (66%) had a TIL level of less than 30% (median age, 59 years [IQR, 41-72]). Five-year DRFS for stage I TNBC was 94% (95% CI, 91%-96%) for patients with a TIL level of 50% or more, compared with 78% (95% CI, 75%-80%) for those with a TIL level of less than 30%; 5-year overall survival was 95% (95% CI, 92%-97%) for patients with a TIL level of 50% or more, compared with 82% (95% CI, 79%-84%) for those with a TIL level of less than 30%. At a median follow-up of 18 years, and after adjusting for age, tumor size, nodal status, histological grade, and receipt of radiotherapy, each 10% higher TIL increment was associated independently with improved iDFS (hazard ratio [HR], 0.92 [0.89-0.94]), RFS (HR, 0.90 [0.87-0.92]), DRFS (HR, 0.87 [0.84-0.90]), and overall survival (0.88 [0.85-0.91]) (likelihood ratio test, P < 10e-6).

Conclusions and Relevance

In patients with early-stage TNBC who did not undergo adjuvant or neoadjuvant chemotherapy, breast cancer tissue with a higher abundance of TIL levels was associated with significantly better survival. These results suggest that breast tissue TIL abundance is a prognostic factor for patients with early-stage TNBC.

Metastatic site patterns by intrinsic subtype and HER2DX in early HER2-positive breast cancer

BACKGROUND

Even with contemporary treatment strategies, more than 10% of HER2-positive early stage breast cancer patients may experience distant metastasis as first event during follow-up. Tools for predicting unique patterns of metastatic spread are needed to plan personalized surveillance. We evaluated how molecular heterogeneity affects the pattern of distant relapse in HER2-positive breast cancer.

METHODS

A total of 677 HER2-positive stage I-III breast cancer patients from ShortHER trial, Cher-LOB trial, and 2 institutional cohorts were included. PAM50 molecular subtypes and research-based HER2DX scores were evaluated. The cumulative incidence of distant relapse as the first event (any site and site specific) was evaluated using competing risk analysis. Median follow-up was 8.4 years. Tests of statistical significance are 2-sided.

RESULTS

Stage III and high HER2DX risk score identified patients at the highest risk of distant relapse as first event (10-year incidence 24.5% and 19.7%, respectively). Intrinsic molecular subtypes were associated with specific patterns of metastatic spread: compared with other subtypes, HER2-enriched tumors were more prone to develop brain metastases (10-year incidence 3.8% vs 0.6%, P = .005), basal-like tumors were associated with an increased risk of lung metastases (10-year incidence 11.1% vs 2.6%, P = .001), and luminal tumors developed more frequently bone-only metastases (10-year incidence 5.1% vs 2.0%, P = .042). When added to stage or HER2DX risk score in competing risk regression models, intrinsic subtype maintained an independent association with site-specific metastases.

CONCLUSIONS

The integration of intrinsic molecular subtypes with stage or HER2DX risk score predicts site-specific metastatic risk in HER2-positive breast cancer, with potential implications for personalized surveillance and clinical trials aimed at preventing site-specific recurrence.

Pregnancy After Breast Cancer in Young BRCA Carriers: An International Hospital-Based Cohort Study

Importance

Young women with breast cancer who have germline pathogenic variants in BRCA1 or BRCA2 face unique challenges regarding fertility. Previous studies demonstrating the feasibility and safety of pregnancy in breast cancer survivors included limited data regarding BRCA carriers.

Objective

To investigate cumulative incidence of pregnancy and disease-free survival in young women who are BRCA carriers.

Design, Setting, and Participants

International, multicenter, hospital-based, retrospective cohort study conducted at 78 participating centers worldwide. The study included female participants diagnosed with invasive breast cancer at age 40 years or younger between January 2000 and December 2020 carrying germline pathogenic variants in BRCA1 and/or BRCA2. Last delivery was October 7, 2022; last follow-up was February 20, 2023.

Exposure

Pregnancy after breast cancer.

Main Outcomes and Measures

Primary end points were cumulative incidence of pregnancy after breast cancer and disease-free survival. Secondary end points were breast cancer-specific survival, overall survival, pregnancy, and fetal and obstetric outcomes.

Results

Of 4732 BRCA carriers included, 659 had at least 1 pregnancy after breast cancer and 4073 did not. Median age at diagnosis in the overall cohort was 35 years (IQR, 31-38 years). Cumulative incidence of pregnancy at 10 years was 22% (95% CI, 21%-24%), with a median time from breast cancer diagnosis to conception of 3.5 years (IQR, 2.2-5.3 years). Among the 659 patients who had a pregnancy, 45 (6.9%) and 63 (9.7%) had an induced abortion or a miscarriage, respectively. Of the 517 patients (79.7%) with a completed pregnancy, 406 (91.0%) delivered at term (≥37 weeks) and 54 (10.4%) had twins. Among the 470 infants born with known information on pregnancy complications, 4 (0.9%) had documented congenital anomalies. Median follow-up was 7.8 years (IQR, 4.5-12.6 years). No significant difference in disease-free survival was observed between patients with or without a pregnancy after breast cancer (adjusted hazard ratio, 0.99; 95% CI, 0.81-1.20). Patients who had a pregnancy had significantly better breast cancer-specific survival and overall survival.

Conclusions and Relevance

In this global study, 1 in 5 young BRCA carriers conceived within 10 years after breast cancer diagnosis. Pregnancy following breast cancer in BRCA carriers was not associated with decreased disease-free survival.

Trial Registration

ClinicalTrials.gov Identifier: NCT03673306.

Peripheral blood lymphocytes predict clinical outcomes in hormone receptor-positive HER2-negative advanced breast cancer patients treated with CDK4/6 inhibitors

Background

Cyclin-Dependent Kinase 4/6 inhibitors (CDK4/6i) combined with Endocrine Therapy (ET) are the standard treatment for patients with Hormone Receptor-positive/HER2-negative advanced breast cancer (HR+/HER2- aBC).

Objectives

While CDK4/6i are known to reduce several peripheral blood cells, such as neutrophils, lymphocytes and platelets, the impact of these modulations on clinical outcomes is unknown.

Design

A multicenter, retrospective-prospective Italian study.

Methods

We investigated the association between baseline peripheral blood cells, or their early modifications (i.e. 2 weeks after treatment initiation), and the progression-free survival (PFS) of HR+/HER2- aBC patients treated with ETs plus CDK4/6i. Random Forest models were used to select covariates associated with patient PFS among a large list of patient- and tumor-related variables.

Results

We evaluated 638 HR+/HER2- aBC patients treated with ET plus CDK4/6i at six Italian Institutions between January 2017 and May 2021. High baseline lymphocyte counts were independently associated with longer PFS [median PFS (mPFS) 20.1 versus 13.2 months in high versus low lymphocyte patients, respectively; adjusted Hazard Ratio (aHR): 0.78; 95% confidence interval (CI): 0.66-0.92; p = 0.0144]. Moreover, patients experiencing a lower early reduction of lymphocyte counts had significantly longer PFS when compared to patients undergoing higher lymphocyte decrease (mPFS 18.1 versus 14.5 months; aHR: 0.82; 95% CI: 0.73-0.93; p = 0.0037). Patients with high baseline lymphocytes and undergoing a lower reduction, or even an increase, of lymphocyte counts during CDK4/6i therapy experienced the longest PFS, while patients with lower baseline lymphocytes and undergoing a higher decrease of lymphocytes had the lowest PFS (mPFS 21.4 versus 11 months, respectively).

Conclusion

Baseline and on-treatment modifications of peripheral blood lymphocytes have independent prognostic value in HR+/HER2- aBC patients. This study supports the implementation of clinical strategies to boost antitumor immunity in patients with HR+/HER2- aBC treated with ETs plus CDK4/6i.

The Impact of COVID-19 on Treatment Practices for Patients With Early Breast Cancer: A Cross-Sectional Study From a Large Cancer Center in Italy

INTRODUCTION

The Coronavirus Disease 2019 (COVID-19) has disrupted health services worldwide. The evidence on the impact of the pandemic on cancer care provision, however, is conflicting. We aimed to audit the management of patients diagnosed with early breast cancer (EBC) during the pandemic in a large, tertiary-level cancer center in Italy.

METHODS

We conducted a cross-sectional study to track the route to first treatment for patients diagnosed with EBC during 2019, 2020, and 2021. We abstracted data for all consecutive patients referred to the Veneto Institute of Oncology (Padua, Italy). We defined as point of contact (POC) the date of the first consultation with a breast cancer specialist of the breast unit. First treatment was defined as either upfront surgery or neoadjuvant chemotherapy (NACT).

RESULTS

We reviewed medical records for 878 patients for whom an MDT report during 2019-2021 (April through June) was available. Of these, 431 (49%) were eligible. The proportion of screen-detected tumors was larger in 2019 and 2021 than in 2020 (59%). Conversely, the proportion of screen-detected tumors was offset by the proportion of palpable tumors in 2020 (P = .004). Distribution of tumor and nodal stage was unchanged over time, but in situ tumors were slightly fewer in 2020 than in 2019 or 2021. The adjusted odds ratio for treatment delay (45 days or more) was 0.87 for 2020 versus 2019 (95% CI, 0.5-1.53) and 0.9 for 2021 versus 2019 (95% CI, 0.52-1.55).

CONCLUSIONS

There was no evidence for major changes in the management of patients with EBC during 2019-2021 and no treatment delays were observed. Our findings suggest that more women presented with palpable nodules at diagnosis, but the stage distribution did not change over time. Validation on a larger cohort of patients is warranted to robustly assess the impact of the COVID-19 pandemic on treatment practices for patients with EBC.

Association of tumor-infiltrating lymphocytes with recurrence score in hormone receptor-positive/HER2-negative breast cancer: Analysis of four prospective studies

BACKGROUND

The clinical value of tumor infiltrating lymphocytes (TILs) in hormone receptor-positive (HR+)/HER2- breast cancer (BC) may be unearthed by focusing on more biologically aggressive tumors. Here we deepen and describe the correlation between RS and TILs, proposing an immuno-genomic model for HR+ /HER2- BC.

METHODS

We enrolled T1-T3, N0-N1 BC patients with available RS® and TILs in the context of four multicenter, prospective studies. RS® and TILs were considered as continuous and categorical variables. RS® was categorized into: 0-10 (low risk), 11-25 (intermediate risk) and 26-100 (high risk); TILs were categorized into: low TILs (0-10%), intermediate TILs (11-59%) and high TILs (60-100%).

RESULTS

811 patients were included. RS distribution was (n = 810): low risk 22.0%, intermediate risk 61.2%, high risk 16.8%. TIL distribution was (n = 455): low TILs 84.6%, intermediate TILs 13.6% and high TILs 1.8%. A significant, weak positive, linear correlation was found between continuous TILs and RS (Pearson coefficient=0.223, p < 0.001). When considering RS and TILs categories, tumors with intermediate/high TIL levels significantly enriched the high RS subgroup (p = 0.006). This was confirmed both within Luminal A and Luminal B cohorts. Among high-RS patients, 16.7% of Luminal A and 26.7% of Luminal B tumors had intermediate/high TILs.

CONCLUSIONS

We observed that RS® and TILs capture only slightly overlapping information on the biology of HR+ /HER2- tumor microenvironment. We demonstrated the feasibility of combining RS and TILs into a composite immuno-genomic model, which may serve the purpose of guiding and focalizing patient selection in the further development of immunotherapy strategies for Luminal-like disease.

Multidisciplinary management of HER2-positive breast cancer with brain metastases: An evidence-based pragmatic approach moving from pathophysiology to clinical data

INTRODUCTION

About 30-50 % of stage IV HER2+ breast cancers (BC) will present brain metastases (BMs). Their management is based on both local treatment and systemic therapy. Despite therapeutic advances, BMs still impact on survival and quality of life and the development of more effective systemic therapies represents an unmet clinical need.

MATERIALS AND METHODS

A thorough analysis of the published literature including ongoing clinical trials has been performed, investigating concepts spanning from the pathophysiology of tumor microenvironment to clinical considerations with the aim to summarize the current and future locoregional and systemic strategies.

RESULTS

Different trials have investigated monotherapies and combination treatments, highlighting how the blood-brain barrier (BBB) represents a major problem hindering diffusion and consequently efficacy of such options. Trastuzumab has long been the mainstay of systemic therapy and over the last two decades other HER2-targeted agents including lapatinib, pertuzumab, and trastuzumab emtansine, as well as more recently neratinib, tucatinib, and trastuzumab deruxtecan, have been introduced in clinical practice after showing promising results in randomized controlled trials.

CONCLUSIONS

We ultimately propose an evidence-based treatment algorithm for clinicians treating HER2 + BCs patients with BMs.

Nine-Week Versus One-Year Trastuzumab for Early Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer: 10-Year Update of the ShortHER Phase III Randomized Trial

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned coprimary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.We present the final analysis of the phase III noninferiority, randomized ShortHER trial comparing 9 weeks versus 1 year of adjuvant trastuzumab with chemotherapy in patients with human epidermal growth factor receptor 2-positive (HER2+) early breast cancer (BC). Women with HER2+ BC were randomly assigned to anthracycline-taxane combinations plus 1-year trastuzumab (arm A, long) or 9-week trastuzumab (arm B, short). Here, we report the second coprimary end point overall survival (OS), updated disease-free survival (DFS), and outcomes according to hormone receptor status, age, and nodal status. At a median follow-up of 9 years, 10-year DFS is 77% versus 78% in the long versus short arm, respectively. Ten-year OS is 89% versus 88% in the long versus short arm, respectively. 10-year DFS rates in the long versus short arm according to nodal status are N0 81% versus 85%; N1-3 77% versus 79%; and N4+ 63% versus 53%. Ten-year OS rates in long versus short arm according to nodal status are N0 89% versus 95%%; N1-3 92% versus 89%; and N4+ 84% versus 64%. The updated analysis of the ShortHER trial shows that 1-year trastuzumab is the standard treatment for patients with HER2+ early BC as noninferiority cannot be claimed. However, numerically, the differences for the patients at low or intermediate risk (N0/N1-3) is negligible, while patients with N4+ have a clear benefit with 1-year trastuzumab.

Characterization of Gut Microbiome Composition in Patients with Triple-Negative Breast Cancer Treated with Neoadjuvant Chemotherapy

INTRODUCTION

Patients with triple-negative breast cancer (TNBC) achieving a pathological complete response (pCR) after neoadjuvant chemotherapy have a better event-free survival. The role of gut microbiome in early TNBC is underexplored.

METHODS

Microbiome was analyzed by 16SrRNA sequencing.

RESULTS

Twenty-five patients with TNBC treated with neoadjuvant anthracycline/taxane-based chemotherapy were included. Fifty-six percent achieved a pCR. Fecal samples were collected before (t0), at 1 (t1), and 8 weeks (t2) from chemotherapy. Overall, 68/75 samples (90.7%) were suitable for microbiome analysis. At t0, pCR group showed a significantly higher α-diversity as compared with no-pCR, (P = .049). The PERMANOVA test on β-diversity highlighted a significant difference in terms of BMI (P = 0.039). Among patients with available matched samples at t0 and t1, no significant variation in microbiome composition was reported over time.

CONCLUSIONS

Fecal microbiome analysis in early TNBC is feasible and deserves further investigation in order to unravel its complex correlation with immunity and cancer.

A Prognostic Model Based on Residual Cancer Burden and Tumor-Infiltrating Lymphocytes on Residual Disease after Neoadjuvant Therapy in HER2+ Breast Cancer

PURPOSE

We aim to evaluate the prognostic significance of tumor-infiltrating lymphocyte on residual disease (RD-TIL) in HER2+ patients with breast cancer who failed to achieve pathologic complete response (pCR) after anti-HER2+ chemotherapy (CT)-based neoadjuvant treatment (NAT). We assessed the feasibility of combining the prognostic information provided by residual cancer burden (RCB) and RD-TILs into a composite score (RCB+TIL).

EXPERIMENTAL DESIGN

HER2+ patients with breast cancer treated with CT+anti-HER2-based NAT at three institutions were retrospectively included. RCB and TIL levels were evaluated on hematoxylin and eosin-stained slides from surgical samples according to available recommendations. Overall survival (OS) was used as an outcome measure.

RESULTS

A total of 295 patients were included, of whom 195 had RD. RCB was significantly associated with OS. Higher RD-TILs were significantly associated with poorer OS as compared with lower RD-TILs (15% cutoff). In multivariate analysis, both RCB and RD-TIL maintained their independent prognostic value. A combined score, RCB+TIL, was calculated from the estimated coefficient of RD-TILs and the RCB index in a bivariate logistic model for OS. The RCB+TIL score was significantly associated with OS. The C-index for OS of the RCB+TIL score was numerically higher than that of RCB and significantly higher than that of RD-TILs.

CONCLUSIONS

We have reported an independent prognostic impact of RD-TILs after anti-HER2+CT NAT, which might underlie an imbalance of the RD microenvironment towards immunosuppressive features. We provided a new composite prognostic score based on RCB+TIL, which was significantly associated with OS and proved to be more informative than the isolated evaluation of RCB and RD-TILs.

PI3K/PTEN/mTOR pathway dynamic tracking and prognostic value in HR+/HER2- BC patients with residual disease after neoadjuvant chemotherapy: a cohort study

AIMS

Hormone receptor-positive (HR)+/HER2- breast cancer (BC) is highly heterogeneous, with PI3K/PTEN/mTOR pathway alterations emerging as possible players within this complexity. We longitudinally tracked PI3K/PTEN/mTOR pathway dynamics from baseline biopsy to residual disease (RD)-and to metastases in case of relapse-in HR+/HER2- BC patients receiving neoadjuvant chemotherapy (NACT).

METHODS

HR+/HER2- BC patients with RD after NACT were identified. We assessed PIK3CA mutational, Pten-loss and phosphorylation levels of mTOR and its substrates (p70S6K and 4EBP1) on baseline biopsies and matched RD samples; in case of disease relapse, we also assessed PIK3CA mutational status on metastatic samples. Recurrence-free survival (RFS) was adopted as endpoint.

RESULTS

92 patient were included. The conversion rate of PIK3CA mutational status was 12.8%; 1 patient acquired PIK3CA mutation at relapse; the rate of Pten conversion was 33.3%; mTOR phosphorylation levels significantly increased from baseline biopsy to RD, while its substrates significantly decreased. Baseline phosphorylated-mTOR significantly predicted poorer RFS in patients with PIK3CA wild-type status; baseline phosphorylated-70S6K was positively associated with RFS.

CONCLUSIONS

We observed that PI3K/PTEN/mTOR pathway is highly dynamic under NACT exposure and the assessment of PIK3CA mutations may capture only a small fraction of such complexity. In this context, mTOR activation trough alternative pathways with respect to PIK3CA signalling may have a crucial role in shaping the molecular landscape of HR+/HER2- BC with RD after NACT. It is imperative to further elucidate the role of PIK3CA and mTOR-dependent pathways in shaping chemoresistance and endocrine resistance in high-risk HR+/HER2- early/locally advanced BC patients.

Radiological response of leptomeningeal metastases according to revised RANO criteria is associated with overall survival in breast cancer patients

Assessment of treatment response in patients (pts) with leptomeningeal metastases (LM) represents a significant challenge and standardized criteria are needed. In 2017, the RANO LM Working Group proposed a standardized scorecard to evaluate MRI findings (further simplified in 2019). Here, we aim to validate the prognostic impact of response to treatment assessed using this tool in a multicentric cohort of breast cancer (BC) pts. Pts with BC-related LM diagnosed at two institutions between 2005 and 2018 were identified. Baseline and follow-up MRI scans were centrally reviewed and response assessment was evaluated using 2019 revised RANO LM criteria. A total of 142 pts with BC-related LM and available baseline brain MRI imaging were identified; 60 of them had at least one follow-up MRI. In this subgroup, median overall survival (OS) was 15.2 months (95%CI 9.5-21.0). At first re-evaluation, radiological response by RANO criteria was: complete response (CR) in 2 pts (3%), partial response (PR) in 12 (20%), stable disease (SD) in 33 (55%) and progression of disease (PD) in 13 (22%). Median OS was 31.1 months (HR 0.10, 95%CI 0.01-0.78) in pts with CR, 16.1 months (HR 0.41, 95%CI 0.17-0.97) in pts with PR, 17.9 months (HR 0.45, 95%CI 0.22-0.91) in pts with SD and 9.5 months in pts with PD (P = .029). A second blinded evaluation showed a moderate interobserver agreement (K = 0.562). Radiological response according to 2019 RANO criteria is significantly associated with OS in pts with BC-related LM, thus supporting the use of this evaluation tool both in trials and clinical practice.

Prognostic significance of HER2-low status in HR-positive/HER2-negative advanced breast cancer treated with CDK4/6 inhibitors

Whether Human Epidermal growth factor Receptor 2 (HER2)-low status has prognostic significance in HR + /HER2- advanced Breast Cancer (aBC) patients treated with first-line Endocrine Therapy plus CDK 4/6 inhibitors remains unclear. In 428 patients evaluated, HER2-low status was independently associated with significantly worse PFS and OS when compared with HER2-0 status. Based on our findings, HER2-low status could become a new prognostic biomarker in this clinical setting.

HER2DX ERBB2 mRNA expression in advanced HER2-positive breast cancer treated with T-DM1

In advanced HER2-positive (HER2+) breast cancer, the new antibody-drug conjugate trastuzumab deruxtecan is more effective compared with trastuzumab emtansine (T-DM1). However, trastuzumab deruxtecan can have considerable toxicities, and the right treatment sequence is unknown. Biomarkers to guide the use of anti-HER2 therapies beyond HER2 status are needed. Here, we evaluated if preestablished levels of ERBB2 mRNA expression according to the HER2DX standardized assay are associated with response and survival following T-DM1. In ERBB2 low, medium, and high groups, the overall response rate was 0%, 29%, and 56%, respectively (P < .001). ERBB2 mRNA was statistically significantly associated with better progression-free survival (P = .002) and overall survival (OS; P = .02). These findings were independent of HER2 immunohistochemistry (IHC) levels, hormone receptor, age, brain metastasis, and line of therapy. The HER2DX risk score (P = .04) and immunoglobulin signature (P = .04) were statistically significantly associated with overall survival since diagnosis. HER2DX provides prognostic and predictive information following T-DM1 in advanced HER2+ breast cancer.

Abstract P3-03-01: The impact of the COVID19 pandemic on treatment practices for patients diagnosed with early breast cancer: a cross-sectional study from a large comprehensive cancer centre in Italy

The impact of the COVID19 pandemic on treatment practices for patients diagnosed with early breast cancer: a cross-sectional study from a large comprehensive cancer centre in Italy.

Introduction: The Coronavirus Disease 2019 (COVID19) has disrupted health services worldwide. The evidence on the impact of the pandemic on cancer care provision, however, is conflicting. Some reports found that management for patients diagnosed with early breast cancer (EBC) during the pandemic did not differ from pre-pandemic practices; other reports suggested that delays in breast cancer surgery may have occurred. We aimed to audit the management of patients diagnosed with EBC during the pandemic in a large, tertiary-level cancer centre in Italy.

Methods: We conducted a cross-sectional study to track the route to first treatment for patients diagnosed with EBC during 2019, 2020, and 2021. We abstracted data for all consecutive patients referred to the Veneto Institute of Oncology (Padua, Italy). We defined as point of contact (POC) the date of the first consultation with a breast cancer specialist of the breast unit. We considered patients with a first POC in the 6 months preceding the multidisciplinary (MDT) meeting and initiating a treatment within 6 months from the POC. We chose the 3-month period April-June because in 2020 it was when health services were first acutely disrupted. We analysed the same period for 2019 and 2021. First treatment was defined as either upfront surgery or neoadjuvant chemotherapy (NACT). The time to first treatment was defined as the interval between the first POC and the first treatment. We used the median time to first treatment in 2019 to define the threshold for treatment delay.

Results: We reviewed medical records for 878 patients for whom an MDT report during 2019-2021 (April through June) was available. Of these, 431 (49%) were eligible: 144 in 2019, 127 in 2020 and 150 in 2021. Median age at first POC was 61 years. The proportion of screen-detected tumours was larger in 2019 and 2021 than in 2020 (59%). Conversely, the proportion of screen-detected tumours was offset by the proportion of palpable tumours in 2020 (44% versus 56%). These differences were statistically significant (chi-square test 11.12, p=0.004). Distribution of tumour and nodal stage was unchanged over time, but in-situ tumours were slightly fewer in 2020 than in 2019 or 2021. The odds ratio for treatment delay (45 days or more) was 0.87 for 2020 versus 2019 (95% CI, 0.5-1.53) and 0.9 for 2021 versus 2019 (95% CI, 0.52-1.55), after adjusting for type of POC, presentation with symptoms, treatment type, tumour stage, nodal stage, and EBC subtype (i.e., luminal, HER2-positive, triple-negative).

Conclusions: There was no evidence for major changes in the management of EBC patients during 2019-2021 and no treatment delays were observed. However, our results show a slight decrease in the absolute number of patients being treated in 2020, offset by an increase in 2021 to levels comparable to 2019. Our findings suggest that disruption of breast cancer screening programmes may have impacted on the characteristics of the patient population, with a larger proportion of women presenting with palpable nodules. Validation on a larger, population-based cohort of patients is warranted to robustly assess the impact of the COVID19 pandemic on treatment practices and outcome for EBC patients.

Characteristics of the population

Citation Format: Fabio Girardi, Sabrina Marini, Francesca Porra, Ilaria Mietto, Sonia Carpentieri, Alberto Marchet, Tania Saibene, Marcello Lo Mele, Tommaso Giarratano, Carlo Alberto Giorgi, Eleonora Mioranza, Cristina Falci, Giovanni Faggioni, Francesca Caumo, Gaia Griguolo, Maria Vittoria Dieci, Valentina Guarneri. The impact of the COVID19 pandemic on treatment practices for patients diagnosed with early breast cancer: a cross-sectional study from a large comprehensive cancer centre in Italy. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-03-01.

Abstract PD9-05: Stromal tumor-infiltrating lymphocytes identify early-stage triple-negative breast cancer patients with favorable outcomes at 10-year follow-up in the absence of systemic therapy: a pooled analysis of 1835 patients

Background: The prognostic value of stromal tumor-infiltrating lymphocytes (TILs) as a biomarker for triple-negative breast cancer (TNBC) has been extensively demonstrated in patients (pts) receiving (neo)adjuvant systemic therapy. In addition, several small studies suggest that a subset of pts with early-stage TNBC and high TILs have excellent long-term outcomes, even in the absence of systemic therapy [1-3]. However, data on the absolute risk of TNBC recurrence according to TIL levels in the absence of systemic therapy are limited and critical to inform the design of future systemic therapy de-escalation clinical trials.

Methods: We conducted an individual patient data pooled analysis of 12 international cohorts of pts with TNBC treated with locoregional therapy but no systemic therapy. TNBC was defined as tumors with estrogen and progesterone receptor of &lt; 1% and HER2 negative (IHC 0, 1+ or IHC 2+ and FISH negative) per local evaluation. TILs were locally assessed in hematoxylin & eosin-stained slides according to the International Immuno-Oncology Biomarker Working Group guidelines (www.tilsinbreastcancer.org). We used the Kaplan-Meier method to assess survival outcomes according to prespecified TIL thresholds: 30% and 50%. Confidence intervals (CI) for survival probabilities were calculated using a percentile bootstrap method. The primary endpoint was invasive disease-free survival (iDFS, STEEP 2.0 definition). Key secondary outcomes included recurrence-free survival (RFS), distant disease-free survival (DDFS) and overall survival (OS).

Results: 1,835 pts diagnosed with TNBC between 1982 and 2017 who did not receive systemic therapy were included. The median age at diagnosis was 56 (IQR 38-71). Menopausal status was known in 1,184 women, of whom 78% were post-menopausal. The median tumor size was 2.0 cm (IQR 1.2-2.6). Most pts (87%) had no axillary lymph node involvement (N0). Most tumors were invasive ductal carcinoma (74%) and grade 3 (70%). The median level of TILs was 15% (IQR 5-40). The median duration of follow-up was 30.4 years (95% CI 29.9, 31.1). A total of 950 (52%) iDFS, 828 (45%) RFS, 767 (42%) DDFS events, and 604 (33%) deaths were observed. In multivariable analyses, higher TILs were independently associated with improved iDFS, RFS, DDFS, and OS beyond clinicopathological factors (likelihood ratio p&lt; 10e-6). Each 10% increment in stromal TILs was associated with an 8% (95% CI: 6-11), 10% (95% CI: 7-13), and 13% (95% CI: 10-15) reduction in the risk of experiencing an iDFS, RFS or DDFS event, and with a 12% (95% CI: 9-15) reduction in the risk of death. iDFS, RFS, DDFS and OS rates according to different TIL thresholds and nodal status are shown in the Table. Of note, the RFS estimates (which exclude second non-breast primaries and contralateral breast cancers) were consistently higher than the iDFS counterparts (which include both), consistent with a high rate of contralateral breast cancers and second primary tumors in this cohort. Notably, patients with node-negative—and especially stage I—TNBC with high TILs had excellent survival rates at 10-year follow-up.

Conclusion: TILs are highly prognostic in pts with systemically untreated early-stage TNBC. Pts with pN0 (and especially stage I) TNBC with high TILs exhibited very favorable long-term outcomes even in the absence of systemic therapy. These data define the natural history of TIL-rich TNBC pts and are crucial to identifying the optimal patient population for future chemotherapy and immunotherapy de-escalation clinical trials.

References:

[1] Leon-Ferre et al, 2017, PMID: 28913760

[2] Park et al, 2019, PMID: 31566659

[3] de Jong et al, 2022, PMID: 35353548

Table 5 and 10-year survival endpoints according TIL level, nodal status, and stage

Citation Format: Roberto A. Leon-Ferre, Sarah Flora Jonas, Roberto Salgado, Sherene Loi, Vincent De Jong, Jodi M. Carter, Torsten Nielson, Samuel Leung, Nazia Riaz, Giuseppe Curigliano, Carmen Criscitiello, Vincent Cockenpot, Matteo Lambertini, Vera Suman, Barbro Linderholm, John WM Martens, Carolien HM van Deurzen, Mieke Timmermans, Tatsunori Shimoi, Shu Yazaki, Masayuki Yoshida, Sung-Bae Kim, Hee Jin Lee, Maria Vittoria Dieci, Guillaume Bataillon, Anne Salomon, Fabrice Andre, Marleen Kok, Sabine Linn, Matthew P. Goetz, Stefan Michiels. Stromal tumor-infiltrating lymphocytes identify early-stage triple-negative breast cancer patients with favorable outcomes at 10-year follow-up in the absence of systemic therapy: a pooled analysis of 1835 patients [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD9-05.

Abstract P4-02-13: Homologous recombination deficiency, RB-loss gene signatures, intrinsic subtype and response to neoadjuvant treatment in HR+/HER2- early breast cancer: a correlative analysis of two phase II trials

Background: Hormone-receptor (HR)+/HER2- breast cancer (BC) is a biologically heterogeneous disease. Homologous recombination deficiency (HRD) and BRCA mutations have been previously reported to be associated with worse outcomes in HR+/HER2- metastatic BC patients receiving CDK4/6 inhibitors and endocrine therapy. Here, we assess the relation between HRD and RB-loss signatures, intrinsic subtyping, the PAM50-based chemo-endocrine score, and response to chemotherapy-based therapy and endocrine treatment in HR+/HER2- early BC. Methods: GIADA is a multicentric neoadjuvant phase II trial that treated premenopausal patients with Luminal B (LumB)-like BC (HR-positive, HER2-negative, with Ki67&gt;20% and/or histologic Grade 3) with a combination of chemotherapy, immunotherapy and endocrine treatment. Expression of 758 genes on baseline tumor samples from all 43 patients was quantified by nCounter platform. The LETLOB phase II trial randomized postmenopausal women with clinical stage II-IIIA HR+/HER2- BC to neoadjuvant letrozole + lapatinib or letrozole + placebo for 6 months (Guarneri, JCO 2014). Gene-expression data (Affymetrix platform) from pre-treatment frozen core-biopsies was available from 66 out of 92 pts enrolled. Intrinsic subtype was assigned using a research-based PAM50 subtype predictor. A published HRD signature (Peng, Nat Commun 2014) and a signature of RB loss (RBsig), previously reported to potentially predict resistance to CDK4/6 inhibitors in HR+/HER2- BC (Malorni, Oncotarget 2016) were computed. The PAM50 based chemo-endocrine score (CES) was calculated using published definition (Prat, CCR 2017). Higher values of CES indicate increased endocrine sensitivity, while lower values indicate chemosensitivity. Association between genomic signatures was assessed through Pearson’s correlation coefficient. Association of genomic signatures with pCR was assessed through logistic regression and association with PEPI scores was assessed through Kruskal-Wallis test. Results: HRD signature levels were significantly higher in non-luminal (Basal-like and HER2-enriched) tumors as compared to Luminal (A or B) tumors (p&gt;0.001 in the GIADA trial, p=0.021 in the LETLOB trial). Moreover, higher levels of HRD signature were associated with higher levels of RB-loss signature (Pearson correlation 0.355, p=0.020 in the GIADA trial; Pearson correlation 0.942, p&lt; 0.001 in the LETLOB trial), higher levels of Basal-like signature (Pearson correlation 0.502, p&lt; 0.001 in the GIADA trial; Pearson correlation 0.373, p=0.002 in the LETLOB trial) and lower levels of CES (Pearson correlation -0.422, p=0.005 in the GIADA trial; Pearson correlation -0.763, p&lt; 0.001 in the LETLOB trial), indicative of higher chemosensitivity. In the GIADA trial, higher levels of HRD signature (p=0.018) and RBloss signature (p=0.073) and lower levels of CES (p=0.007) were associated with higher pCR rates after chemo, endocrine and immunotherapy. In the LETLOB trial, lower levels of HRD signature (p=0.068) and RBloss signature (p=0.042) and higher levels of CES (p=0.050) were associated with higher sensitivity to endocrine treatment (lower PEPI scores, 0 vs 1-3 vs 4 or more, after neoadjuvant letrozole). Conclusions: In HR+/HER2- early BC, HRD gene signatures, RB-loss gene signatures and non-luminal (especially Basal-like) intrinsic subtyping are associated with each other and associated with higher sensitivity to chemotherapy-based therapy and lower sensitivity to endocrine treatment. These observations might help correctly tailor systemic therapy, including biologic agents, in patients with HR+/HER2- early and advanced BC.

Citation Format: Gaia Griguolo, Federica Miglietta, Laia Paré, Daniele G. Generali, Antonio Frassoldati, Antonino Musolino, Simon Spazzapan, Grazia Vernaci, Tommaso Giarratano, Marcello Lo Mele, Giancarlo Bisagni, Federico Piacentini, Enrico Tagliafico, Katia Cagossi, Francesca Schiavi, Claudia Pinato, Aleix Prat, Valentina Guarneri, Maria Vittoria Dieci. Homologous recombination deficiency, RB-loss gene signatures, intrinsic subtype and response to neoadjuvant treatment in HR+/HER2- early breast cancer: a correlative analysis of two phase II trials [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-02-13.

Abstract PD7-08: Gene Expression Profiling of Breast Cancer Brain Metastasis shows enrichment for non-luminal subtypes with potential prognostic implications

Background: The incidence of breast cancer (BC) brain metastases (BM) is increasing as a result of both improved diagnostic techniques and longer survival due to better treatment approaches. However, the biological complexity of BCBMs is still poorly understood. We here evaluate the genomic profile of BCBMs and assess its prognostic implications.

Methods: Clinical data and BM samples (FFPE) from BC patients undergoing neurosurgery (2003-2019) at three institutions were collected. Hormone receptor (HR) and HER2 status were evaluated on the BCBM. RNA extracted from BM samples was used to measure the expression of 758 BC–related genes and 18 housekeeping genes using the Breast Cancer 360 Panel on an nCounter platform (NanoString Technologies). Intrinsic molecular subtyping was determined using the previously reported PAM50 subtype predictor (Parker et al. JCO 2009). Median overall survival from neurosurgery (OS) was calculated using the Kaplan-Meier method. The correlations between expression of each gene/PAM50 signature, BC subtype and OS were studied using univariate and multivariate Cox-models.

Results: Sixty-five BCBM samples were analyzed: 32% (N=21) were HR+/HER2-, 38% (N=25) HER2+ and 29% (N=19) HR-/HER2-. With a median follow-up of 33 months, no clinical variable was significantly associated with OS, despite a trend towards a shorter survival for patients with HR-/HER2- BMs, as compared to patients with HR+/HER2- and HER2+ subtypes (median OS 9.4 versus 22.1 and 20.0 months, respectively, log-rank p=NS).

The intrinsic subtype distribution, as assessed by gene-expression profiling, was 37% Basal-like, 46% HER2-enriched (HER2-E), 15% Luminal B and 2% Normal-like. Non-luminal subtypes (basal-like and HER2-E) were extensively represented, both overall and in each BC subtype (52% in HR+/HER2- subgroup, 96% in HER2+ subgroup, see Table).

The PAM50 basal-like signature was significantly associated with a worse OS (HR 2.7, 95% CI 1.0-7.2, p=0.045), even after correcting for BC subtype (HR 5.2, 95% CI 1.1-23.4, p=0.032). In fact, even within the subgroup of HR+/HER2- BCBMs, the PAM50 basal-like signature was strongly associated with a worse OS (HR 92.6, 95% CI 5.0-1860.1, p=0.003) and patients with basal-like HR+/HER2- BCBMs presented a median OS similar to patients with HR-/HER2- BCBMs (mOS 9.0 vs 9.4 months).

We identified 36 genes whose high expression was significantly associated with a worse OS (p&lt; 0.05) and one gene (LINC02381) whose high expression was significantly associated with better OS (p&lt; 0.05); for 33 of these genes (BCL11A, BMP2, BNIP3, CAV1, CDH3, CDK6, CKB, CRYAB, CXCL12, EGFR, EYA4, FOXC1, FZD8, FZD9, GABRP, GAS1, GDF5, GPC4, IL6, KRT17, KRT5, KRT6B, KRT7, LAMB3, LINC02381, MYC, NOTCH1, PRKX, PSAT1, RUNX3, SNAI1, SPRY2, TTYH1), the association was confirmed even after correcting for BC subtype (p&lt; 0.05).

Conclusions: Non-luminal intrinsic subtypes are extensively represented in resected BCBMs, even if clinically classified as HR+/HER2-. Our data suggest that basal-like genomic features might be enriched in BCBMs and might be associated with worse survival.

Distribution of PAM50 intrisic subtyping on the 65 brain metastases evaluated according to hormone receptor (HR) and HER2 status

Citation Format: Gaia Griguolo, Maria Vittoria Dieci, Susan Fineberg, claudia Pinato, Michele Bottosso, Luc Bauchet, Federica Miglietta, Jack Jacob, Giovanni Zarrilli, Valérie Rigau, Maria Cristina Guarascio, Francesca Zanconato, Francesca Schiavi, Matteo Fassan, William Jacot, Stefano Piccolo, Amelie Darlix, Valentina Guarneri. Gene Expression Profiling of Breast Cancer Brain Metastasis shows enrichment for non-luminal subtypes with potential prognostic implications [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD7-08.

Abstract P4-02-30: Association between tumor infiltrating lymphocytes (TILs) and the HER2DX assay in early-stage of HER2-positive (HER2+) breast cancer

Background: The HER2DX assay is a genomic test in early-stage HER2-positive (HER2+) breast cancer that provides prognostic and predictive information. HER2DX is a supervised learning algorithm incorporating tumor size, nodal staging, and 4 gene expression signature scores (immune/IGG, tumor cell proliferation, luminal differentiation and the expression of the HER2 amplicon). Among them, the IGG signature is associated with both overall survival and probability of achieving a pathologic complete response (pCR). Here, we studied the association of percentage (%) of tumor infiltrating lymphocytes (TILs) with HER2DX scores, immune genes and other breast cancer-related genes. Methods: HER2DX and %TILs were evaluated in 670 formalin-fixed paraffin-embedded (FFPE) samples of HER2+ breast cancer, including in 3 clinical studies SHORTHER (n=437), PAMELA (n=86), a cohort of patients treated with anti-HER2 therapy plus chemotherapy at Hospital Clínic of Barcelona (n=147). The %TILs were quantified by histological evaluation with hematoxylin eosin staining according to International TILs Working Group guidelines. The nCounter platform determined the expression of 192 genes and HER2DX scores. Pearson correlations (Cor) and Significance Analysis of Microarrays (SAM) with a false-discovery rate (FDR) &lt; 5% assessed the association between %TILs and the expression of individual genes or HER2DX signature scores. Results: A moderate correlation was observed between %TILs and the immune IGG signature (Cor=0.56, p&lt; 0.001). Of note, 171 (25.52%) cases had low %TILs (&lt; 30%) and high IGG score, while 1 (0.15%) case had high %TILs (≥30%) and low IGG score. The %TILs were significantly associated with the expression of immune genes, ERBB2, IGG signature and HER2 amplicon score, and negatively associated with the expression of luminal genes (i.e., ESR1, PRG and BCL2). An unclear relationship between TILs and proliferation genes was observed. Finally, moderate correlations were observed between %TILs and HER2DX pCR score (Cor=0.48, p&lt; 0.001) and between %TILs and HER2DX risk score (Cor=0.33, p&lt; 0.001). Conclusions: Important differences exist between the %TILs and the HER2DX IGG signature in early-stage HER2+ breast cancer. The %TILs should not be used to predict the HER2DX scores. Biologically, a higher %TILs indirectly capture a higher ERBB2 expression and a lower expression of luminal genes, both associated with response to anti-HER2 treatment.

Citation Format: Esther Sanfeliu, Fara Brasó-Maristany, Maria Vittoria Dieci, Mercedes Marín-Aguilera, Blanca González-Farré, Gaia Griguolo, Tomas Pascual, Patricia Galván, Laura Angelats, Oleguer Castillo, Paula Blasco, Valeria Sirenko, Pedro Jares, Joan Antón Puig-Butillé, Laia Paré, Antonio Martínez, Antonio Llombart-Cussac, Javier Cortés, Ana Vivancos, Patricia Villagrasa, Joel S Parker, Charles M Perou, Aleix Prat, PierFranco Conte, Valentina Guarneri. Association between tumor infiltrating lymphocytes (TILs) and the HER2DX assay in early-stage of HER2-positive (HER2+) breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-02-30.

Abstract P2-11-12: Pattern of distant relapse according to intrinsic molecular subtype in patients with HER2-positive breast cancer: a combined analysis of ShortHER, CherLOB, and two institutional cohorts

Background: All intrinsic molecular subtypes are represented among HER2-positive breast cancer, with implications on clinical outcome and treatment sensitivity. The impact of molecular subtypes on the pattern and site of relapse is largely unexplored.

Methods: 677 patients with HER2-positive early breast cancer from the Shorther trial (n=437), the CherLOB trial (n=84) and two Institutional cohorts (Istituto Oncologico Veneto IRCCS Padova n=39 and Hospital Clinic Barcelona n=117) were included. Only patients with available PAM50 intrinsic molecular subtyping were considered. We analyzed the incidence of distant relapse (at any site and at specific sites) as the first event. Cumulative incidence was estimated according to competing risk analysis (Fine and Gray’s method). Competing risk regression was used to calculate the subdistribution Hazard Ratios (subHR) and their 95% Confidence Interval (CI).

Results: The distribution of molecular subtypes was: 130 LumA (19%), 75 LumB (11%), 347 HER2-e (51%), 46 Basal (7%), 79 Normal (12%). Median follow up was 8.4 years (95%CI 8.2-8.6). The 10-yr cumulative incidence rates of distant relapse as first event were: LumA 7.9%, LumB 14.8%, HER2-e 14.7%, Basal 15.5%, Normal 10.4% (HER2-e vs LumA: SubHR 2.21, 95%CI 1.05-4.64, p=0.037). Table 1 shows the 5-yr and 10-yr cumulative incidence rates of distant metastases at specific sites (as first event) according to intrinsic subtype. HER2-e enriched and Basal tumors were more prone as compared to other subtypes to develop brain and lung metastasis as first event, respectively. Isolated brain metastases without extracranial disease occurred only in patients with HER2-e tumors. All brain metastases as first event occurred within 5 years from diagnosis. Bone-only disease as first event was less frequent in HER2-e and Basal subtype (subHR HER2-e vs LumA: 0.32, 95%CI 0.10-10.4. p=0.058). Next, we analyzed the frequency of site-specific first metastasis among patients who experienced a distant metastasis as first event (n=77). Lung metastases were more frequent in Basal tumors (LumA 25.0%, LumB 20.0%, HER2-e 24.4%, Basal 71.4%, Normal 0.0%, p=0.037) and bone metastases were more frequent in Luminal tumors (LumA 100.0%, LumB 60.0%, HER2-e 31.1%, Basal 42.9%, Normal 57.1%, p=0.006). Among 45 HER2-e patients with a first distant relapse, 25.6% were diagnosed with a brain metastasis and 15.6% had brain-only disease. Conclusions: Molecular subtypes influence the metastatic behaviour of clinically HER2-positive breast cancer. These results, if further validated, may have implication in planning personalized monitoring strategies.

Table 1. 5-yr and 10-yr cumulative incidence rates of distant metastasis at specific sites (as first event) according to intrinsic subtype.

Citation Format: Maria Vittoria Dieci, Giancarlo Bisagni, Stefania Bartolini, Antonio Frassoldati, Daniele Giulio Generali, Federico Piacentini, Gaia Griguolo, Enrico Tagliafico, Fara Brasó-Maristany, Nuria Chic, Francesca Porra, Roberto Vicini, Roberto D’Amico, Sara Balduzzi, Aleix Prat, PierFranco Conte, Valentina Guarneri. Pattern of distant relapse according to intrinsic molecular subtype in patients with HER2-positive breast cancer: a combined analysis of ShortHER, CherLOB, and two institutional cohorts. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-11-12.

Economic Evaluation for Palbociclib Plus Fulvestrant vs Ribociclib Plus Fulvestrant and Abemaciclib Plus Fulvestrant in Endocrine-Resistant Advanced or Metastatic Breast Cancer in Italy

Background

To date, no study evaluated the cost-effectiveness of palbociclib (PAL) plus fulvestrant (FUL) vs ribociclib (RIB) plus FUL and abemaciclib (ABM) plus FUL in Italy. Cost-effectiveness analysis comparing the three cyclin-dependent 4/6 kinase inhibitors in combination with endocrine therapies for the management of postmenopausal women with HR+, HER2- advanced or metastatic breast cancer in Italy was developed.

Material and Methods

To assess the cost-effectiveness of PAL plus FUL vs RIB plus FUL and ABM plus FUL, a cost-minimization has been carried out with a conservative scenario considering three CDK4/6 inhibitors with equal effectiveness in terms of overall survival (OS) (MAIC, Rugo et al 2021). Adverse events (AEs) associated with all therapies were obtained from clinical trials. Ad-hoc analysis was performed to estimate the cost-effectiveness considering the quality-of-life (QoL) data (Lloyd et al 2006).

Results

Cost-minimization inputs were drugs, visits and exams, AE monitoring and best supportive care (BSC) before the progression state, active and BSC in the progression and terminal phase of the last two weeks of life. Given the comparability of PAL, RIB and ABM in terms of efficacy, this analysis demonstrated slight economic savings over a lifetime for PAL. Results showed saving per patient of €305 (lifetime) when PAL is compared with RIB; for PAL vs ABM a saving of €243 (lifetime) in a conservative scenario. Results of a budget impact analysis showed a potential savings of €319,563 for PAL vs RIB and €297,544 for PAL vs ABM. When QoL data were considered, results may favor PAL due to the lower impact of AE with savings and improvement in the QoL related to fewer AE.

Conclusion

From the Italian perspective, a cost-saving profile associated with the use of PAL+FUL for the management of advanced/metastatic HR+/HER2- breast cancer compared to RIB+FUL and ABM+FUL emerged.

Abstract HER2-02: HER2-02 HER2-Low Status is Associated with Worse Clinical Outcomes in Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer Patients Treated With First-Line Cyclin-Dependent Kinase 4/6 Inhibitors Plus Endocrine Therapy

Introduction: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in combination with endocrine therapy (ET) are the standard first-line treatment for patients with hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (HR+/HER2- aBC). HER2-low BC, which is defined by an IHC score for HER2 of 1+ or 2+ with negative ISH assay, accounts for more than half of all HR+/HER2- aBC cases, and it is associated with remarkable clinical benefit from the novel anti-HER2 antibody drug conjugate (ADC) trastuzumab-deruxtecan. Evidence on the prognostic impact of HER2-low status is controversial in both limited-stage and advanced BC. Here, we sought to investigate the possible prognostic relevance of HER2-low status in a population of aBC patients treated with CDK4/6i plus ET. Methods: We conducted a retrospective-prospective study in six Italian Cancer Centers to investigate the impact of HER2 status (low vs. 0) on the progression-free survival (PFS) and overall survival (OS) of consecutive HR+/HER2- aBC patients treated with CDK4/6i plus ET (aromatase inhibitors or fulvestrant) as a first-line therapy. In the main study analysis, we considered HER2 status in the last tumor assessment (i.e., primary tumor, or, when available, a metastatic lesion). We also performed a subgroup analysis including only patients with HER2 status evaluation in a metastatic lesion collected before CDK4/6i plus ET therapy initiation. The association between HER2 status (low vs. 0) and PFS or OS was evaluated using log-rank test and Cox regression modeling. Results: We evaluated 767 consecutive HR+/HER2- aBC patients treated with CDK4/6i plus ET between January 2017 and January 2022. Of these, 436 patients (56.8%) received CDK4/6i plus ET as a first-line therapy, and they were included in this analysis. Median age was 63 years (range 27-87), and 362 patients (83.0%) were postmenopausal. The majority of patients were treated with palbociclib (68.3%), while 91 (20.9%) and 47 (10.8%) patients received ribociclib and abemaciclib, respectively. Regarding HER2 status, 269 (62.9%) patients had HER2-low tumors, while 159 (37.1%) patients had HER2-0 neoplasms. HER2-low status was associated with significantly lower PFS when compared to HER2-0 status [median PFS (mPFS) 23.6 vs. 32.3 months, respectively; p=0.014]. HER2-low status was also associated with significantly worse OS (mOS 48.7 vs 58.3 months, respectively; p=0.025). These results were confirmed in multivariable models adjusting the impact of HER2 status for clinically-relevant covariates, namely estrogen receptor status, Ki-67, age, number of metastatic sites, presence of liver metastases, disease free interval, ECOG Performance Status. In this analysis, HER2-low status, compared with HER2-0 status, was independently associated with worse PFS [adjusted Hazard Ratio (aHR): 1.62; 95% confidence interval (CI): 1.17-2.24; p&lt; 0.01] and OS (aHR: 1.74; 95% CI: 1.09-2.76; p=0.019). Subgroup analysis conducted in the subset of 256 patients with available metastatic tumor samples collected before CDK4/6i plus ET initiation confirmed that HER2-low status (n=157), when compared to HER2-0 status (n=99), was independently associated with worse PFS (mPFS 24.5 vs 35.2 months, p=0.01; aHR 2.07; 95% CI: 1.28-3.34, p&lt; 0.01) and worse OS (mPFS 48.7 vs 72.3 months, p=0.027; aHR 3.12; 95% CI 1.44-6.77, p&lt; 0.01). Conclusions: This multicenter Italian study revealed that HER2-low status has independent, negative prognostic value in patients with HR+/HER2- aBC treated with CDK4/6i plus ET in the first-line setting. Our results suggest that HER2-low status might be associated with different clinical benefit from standard anticancer therapies in specific clinical settings. The definition of treatment algorithms also taking into account HER2 status is a clinical priority in patients with HR+/HER2- aBC.

Citation Format: Emma Zattarin, Caterina Sposetti, Rita Leporati, Luigi Mariani, Alice Menichetti, Chiara Corti, Chiara Benvenuti, Giovanni Fucà, Riccardo Lobefaro, Francesca Ligorio, Daniele Presti, Leonardo Provenzano, Andrea Vingiani, Gaia Griguolo, Marianna Sirico, Ottavia Bernocchi, Antonio Marra, Paola Zagami, Elisa Agostinetto, Flavia Jacobs, Pierluigi Di Mauro, Andrea Esposito, Carlo Alberto Giorgi, Luca Lalli, Laura Boldrini, Pier Paolo Maria Berton Giachetti, Ambra Carnevale Schianca, Valentina Guarneri, Rebecca Pedersini, Agnese Losurdo, Alberto Zambelli, Daniele Giulio Generali, Giuseppe Curigliano, Giancarlo Pruneri, Filippo de Braud, Maria Vittoria Dieci, Claudio Vernieri. HER2-02 HER2-Low Status is Associated with Worse Clinical Outcomes in Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer Patients Treated With First-Line Cyclin-Dependent Kinase 4/6 Inhibitors Plus Endocrine Therapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr HER2-02.

Optimizing choices and sequences in the diagnostic-therapeutic landscape of advanced triple-negative breast cancer: An Italian consensus paper and critical review

Triple-negative (TN) metastatic breast cancer (mBC) represents the most challenging scenario withing mBC framework, and it has been only slightly affected by the tremendous advancements in terms of drug availability and survival prolongation we have witnessed in the last years for advanced disease. However, although chemotherapy still represents the mainstay of TN mBC management, in the past years, several novel effective agents have been developed and made available in the clinical practice setting. Within this framework, a panel composed of a scientific board of 17 internationally recognized breast oncologists and 42 oncologists working within local spoke centers, addressed 26 high-priority statements, including grey areas, regarding the management of TN mBC. A structured methodology based on a modified Delphi approach to administer the survey and the Nominal Group Technique to capture perceptions and preferences on the management of TN mBC within the Italian Oncology community were adopted. The Panel produced a set of prioritized considerations/consensus statements reflecting the Panel position on diagnostic and staging approach, first-line and second-line treatments of PD-L1-positive/germline BRCA (gBRCA) wild-type, PD-L1-positive/gBRCA mutated, PD-L1-negative/gBRCA wild-type and PD-L1-negative/gBRCA mutated TN mBC. The Panel critically and comprehensively discussed the most relevant and/or unexpected results and put forward possible interpretations for statements not reaching the consensus threshold.

Prognostic impact of extracranial disease control in HER2+ breast cancer-related brain metastases

BACKGROUND

Brain metastases (BM) are common among HER2+ breast cancer (BC) and prognostic stratification is crucial for optimal management. BC-GPA score and subsequent refinements (modified-GPA, updated-GPA) recapitulate prognostic factors. Since none of these indexes includes extracranial disease control, we evaluated its prognostic value in HER2+ BCBM.

METHODS

Patients diagnosed with HER2+ BCBM at Istituto Oncologico Veneto-Padova (2002-2021) and Montpellier Cancer Institute (2001-2015) were included as exploratory and validation cohorts, respectively. Extracranial disease control at BM diagnosis (no disease/stable disease/response vs. progressive disease) was evaluated.

RESULTS

In the exploratory cohort of 113 patients (median OS 12.2 months), extracranial control (n = 65, 57.5%) was significantly associated with better OS at univariate (median OS 17.7 vs. 8.7 months, p = 0.005) and multivariate analysis after adjustment for BC-GPA (HR 0.61, 95% CI 0.39-0.94), modified-GPA (HR 0.64, 95% CI 0.42-0.98) and updated-GPA (HR 0.63, 95% CI 0.41-0.98). The prognostic impact of extracranial disease control (n = 66, 56.4%) was then confirmed in the validation cohort (n = 117) at univariate (median OS 20.2 vs. 9.1 months, p < 0.001) and multivariate analysis adjusting for BC-GPA (HR 0.41, 95% CI 0.27-0.61), modified-GPA (HR 0.44, 95% CI 0.29-0.67) and updated-GPA (HR 0.42, 95% CI 0.28-0.63).

CONCLUSIONS

Extracranial disease control provides independent prognostic information in HER2+ BCBM beyond commonly used prognostic scores.

Development of a nomogram for predicting pathological complete response in luminal breast cancer patients following neoadjuvant chemotherapy

Background

Given the low chance of response to neoadjuvant chemotherapy (NACT) in luminal breast cancer (LBC), the identification of predictive factors of pathological complete response (pCR) represents a challenge. A multicenter retrospective analysis was performed to develop and validate a predictive nomogram for pCR, based on pre-treatment clinicopathological features.

Methods

Clinicopathological data from stage I-III LBC patients undergone NACT and surgery were retrospectively collected. Descriptive statistics was adopted. A multivariate model was used to identify independent predictors of pCR. The obtained log-odds ratios (ORs) were adopted to derive weighting factors for the predictive nomogram. The receiver operating characteristic analysis was applied to determine the nomogram accuracy. The model was internally and externally validated.

Results

In the training set, data from 539 patients were gathered: pCR rate was 11.3% [95% confidence interval (CI): 8.6-13.9] (luminal A-like: 5.3%, 95% CI: 1.5-9.1, and luminal B-like: 13.1%, 95% CI: 9.8-13.4). The optimal Ki67 cutoff to predict pCR was 44% (area under the curve (AUC): 0.69; p < 0.001). Clinical stage I-II (OR: 3.67, 95% CI: 1.75-7.71, p = 0.001), Ki67 ⩾44% (OR: 3.00, 95% CI: 1.59-5.65, p = 0.001), and progesterone receptor (PR) <1% (OR: 2.49, 95% CI: 1.15-5.38, p = 0.019) were independent predictors of pCR, with high replication rates at internal validation (100%, 98%, and 87%, respectively). According to the nomogram, the probability of pCR ranged from 3.4% for clinical stage III, PR > 1%, and Ki67 <44% to 53.3% for clinical stage I-II, PR < 1%, and Ki67 ⩾44% (accuracy: AUC, 0.73; p < 0.0001). In the validation set (248 patients), the predictive performance of the model was confirmed (AUC: 0.7; p < 0.0001).

Conclusion

The combination of commonly available clinicopathological pre-NACT factors allows to develop a nomogram which appears to reliably predict pCR in LBC.

PARP-inhibitors for BRCA1/2-related advanced HER2-negative breast cancer: A meta-analysis and GRADE recommendations by the Italian Association of Medical Oncology

BACKGROUND

Approximately 5-10% of unselected breast cancer (BC) patients retain a hereditary predisposition related to a germline mutation in BRCA1/2 genes. The poly-ADP ribose polymerase (PARP)-inhibitors olaparib and talazoparib have been granted marketing authorization by both FDA and EMA for adults with BRCA1/2 germline mutations and HER2-negative (HER2-) advanced BC based on the results from the phase III OlympiAd and EMBRACA trials.

METHODS

The panel of the Italian Association of Medical Oncology (AIOM) Clinical Practice Guidelines on Breast Cancer addressed two critical clinical questions, adopting the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach and the Evidence to Decision framework (EtD), to develop recommendations on the use of PARP-inhibitors, with respect to single-agent chemotherapy, in patients with BRCA-related triple-negative (clinical question 1) and hormone receptor-positive (HR+)/HER2- (clinical question 2) advanced BC.

RESULTS

Two studies were eligible (OlympiAd and EMBRACA). For both clinical questions, the Panel judged the benefit/harm balance probably in favor of the intervention, given the favorable impact in terms of PFS, ORR, and QoL at an acceptable cost in terms of toxicity; the overall certainty of the evidence was low. The panel's final recommendations were conditional in favor of PARP-inhibitors over single-agent chemotherapy in both HR+/HER2-and triple-negative BC. Finally, the Panel identified and discussed areas of uncertainty calling for further exploration.

CONCLUSIONS

The Panel of AIOM BC Clinical Practice Guideline provided clinical recommendations on the use of PARP-inhibitors, with respect to single-agent chemotherapy, in patients with BRCA-related HER2-advanced BC by adopting the GRADE methodology.

HER2DX genomic test in HER2-positive/hormone receptor-positive breast cancer treated with neoadjuvant trastuzumab and pertuzumab: A correlative analysis from the PerELISA trial

Background

HER2DX is a prognostic and predictive assay in early-stage HER2-positive breast cancer based on clinical features and the expression of 4 gene signatures (immune, proliferation, luminal differentiation and HER2 amplicon), including ERBB2 mRNA levels. Here, we evaluated the ability of HER2DX to predict efficacy of a de-escalated, chemotherapy-free neoadjuvant regimen in HER2-positive/hormone receptor-positive breast cancer.

Methods

HER2DX was evaluated on pre-treatment tumour samples from the PerELISA phase II study focused on postmenopausal patients with operable HER2-positive/hormone receptor-positive breast cancer. Patients received 2-weeks of letrozole, and then underwent a re-biopsy for Ki67 evaluation. Patients with endocrine therapy sensitive disease (ESD) (i.e., >20.0% Ki67 relative reduction at week 2) continued letrozole and 5 cycles of trastuzumab and pertuzumab. Primary aim was to test the ability of HER2DX risk-score, HER2DX pCR score and HER2DX ERBB2 mRNA score (as continuous variables and group categories) to predict pathological complete response (pCR) in patients with ESD. Logistic regression and receiver–operator curve (ROC) analysis assessed associations of HER2DX scores with pCR and ESD.

Findings

HER2DX was evaluated in 55 patients (86.0%) enrolled in PerELISA and 40 patients (73.0%) had ESD. The pCR rate in patients with ESD was 22.5% (9/40). In this group, HER2DX pCR score and HER2DX ERBB2 mRNA score were significantly associated with pCR (p = 0.008 and p = 0.003, univariate logistic regression model; area under ROC [AUC] = 0.803 and 0.896). The pCR rate in low, medium, and high HER2DX pCR score groups was 7.7% (2/26), 46.2% (6/13) and 100.0% (1/1), respectively. The pCR rate in low, medium, and high HER2DX ERBB2 score groups was 0.0% (0/12), 7.7% (1/13) and 53.3% (8/15), respectively. HER2DX pCR score was also significantly associated with Ki-67 response following 2-weeks of letrozole (p = 0.002, univariate logistic regression model; AUC = 0.775). The rate of ESD in low, medium, and high HER2DX pCR score groups was 89.7% (26/29), 65.0% (13/20) and 16.7% (1/6), respectively.

Interpretation

HER2DX predicts response following neoadjuvant letrozole in combination with dual HER2 blockade with trastuzumab and pertuzumab in early-stage HER2-positive/hormone receptor-positive breast cancer.

Funding

This study received funding from Reveal Genomics.

Multiplexed In Situ Spatial Protein Profiling in the Pursuit of Precision Immuno-Oncology for Patients with Breast Cancer

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of many solid tumors. In breast cancer (BC), immunotherapy is currently approved in combination with chemotherapy, albeit only in triple-negative breast cancer. Unfortunately, most patients only derive limited benefit from ICIs, progressing either upfront or after an initial response. Therapeutics must engage with a heterogeneous network of complex stromal-cancer interactions that can fail at imposing cancer immune control in multiple domains, such as in the genomic, epigenomic, transcriptomic, proteomic, and metabolomic domains. To overcome these types of heterogeneous resistance phenotypes, several combinatorial strategies are underway. Still, they can be predicted to be effective only in the subgroups of patients in which those specific resistance mechanisms are effectively in place. As single biomarker predictive performances are necessarily suboptimal at capturing the complexity of this articulate network, precision immune-oncology calls for multi-omics tumor microenvironment profiling in order to identify unique predictive patterns and to proactively tailor combinatorial treatments. Multiplexed single-cell spatially resolved tissue analysis, through precise epitope colocalization, allows one to infer cellular functional states in view of their spatial organization. In this review, we discuss-through the lens of the cancer-immunity cycle-selected, established, and emerging markers that may be evaluated in multiplexed spatial protein panels to help identify prognostic and predictive patterns in BC.

Oligometastatic breast cancer: Dissecting the clinical and biological uniqueness of this emerging entity. Can we pursue curability?

Metastatic breast cancer represents an incurable condition, however, the increasing interest towards the oligometastatic entity is now challenging this assumption. Up to 20% of patients with metastatic breast cancer present with oligometastatic disease, which refers to metastatic breast cancer presenting or recurring with limited metastatic burden. In the last years, progressive advancements in imaging techniques, the growing availability of minimally invasive locoregional treatments, alongside the increasing expectations from a patient perspective, have contributed to rising the awareness towards this emerging entity. In the present work we comprehensively reviewed available evidence regarding oligometastatic breast cancer, focusing on clinical and biological notions virtually supporting the adoption of a curative approach when treating this condition. We also discussed main areas of uncertainties, providing a research agenda that may guide and fine-tune the future investigation in this field.

Leptomeningeal metastases in patients with human epidermal growth factor receptor 2 positive breast cancer: real-world data from a multicentric European cohort

In patients with human epidermal growth factor receptor 2 positive (HER2+) breast cancer, leptomeningeal metastases (LM) are a rare but often a fatal clinical scenario. In this multicentric study, clinical and pathologic characteristics of patients with HER2+ breast cancer developing LM were described, as well as survival outcomes. Data were gathered retrospectively from medical records of 82 patients with advanced HER2+ breast cancer and LM treated between August 2005 and July 2020. Following LM diagnosis, 79 (96.3%) patients received at least one line of anti‐HER2 therapy, 25 (30.5%) patients received intrathecal therapy and 58 (70.7%) patients received radiotherapy. Overall survival (OS) was 8.3 months (95% confidence interval [CI] 5.7‐11), 1‐year OS was 42%, and 2‐year OS was 21%. At univariate analysis, patients who were treated after 2010, had better Karnofsky performance status, were free of neurological symptoms, had better prognostic, received chemotherapy (OS difference 9.4 months, P = .024), or monoclonal antibodies (trastuzumab ± pertuzumab; OS difference 6.1 months; P = .013) after LM diagnosis, had a statistically significantly longer OS. Presence of neurological symptoms (hazard ratio 3.32, 95% CI 1.26‐8.73; P = .015) and not having received radiotherapy (hazard ratio 2.02, 95% CI 1.09‐3.72; P = .024) were all associated with poorer OS at multivariate analysis. To summarize, not having neurological symptoms and receiving RT at LM diagnosis were associated with prolonged OS in our cohort. Survival seemed to be prolonged with multimodality treatment, which included targeted therapy, chemotherapy, and RT to the LM sites.

Type of endocrine therapy and DFS in patients with early HER2+/HR+ BC: Analysis from the phase III randomized ShortHER trial

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Background: Optimal adjuvant endocrine therapy for HER2+/HR+ patients treated with chemotherapy and trastuzumab is still unclear. We evaluated the impact of the type of endocrine therapy on DFS in patients with HER2+/HR+ breast cancer enrolled in the phase III ShortHER trial. Methods: The Short-HER study randomized 1254 patients with HER2+ early breast cancer to receive 9 weeks vs 1 year of adjuvant trastuzumab combined with anthracycline-taxane chemotherapy. The type of adjuvant endocrine was collected every 6 months during the first 5 years of follow-up and was classified as: aromatase inhibitor (AI), tamoxifen and aromatase inhibitor (TAM-AI, in case of both drugs were administered for at least 1 year each), or tamoxifen (TAM). For premenopausal patients, the use of GnRH analogue was also collected. DFS was calculated from randomization to disease recurrence (locoregional or metastatic), second primary invasive cancer, or death. Results: 853 patients with HR+ BC (ER and/or PgR >10%) were included: 60% postmenopausal, 40% premenopausal. The pattern of endocrine therapy was: 55% AI, 22% TAM, 15% TAM-AI (8% missing data). Among premenopausal patients, 51% received GnRH. At a median follow up of 8.7 years (IQR 7.6-9.0), patients who received AI had a significantly better DFS as compared to patients who received TAM or TAM-AI: 7-yr DFS 87.3% vs 81.7%, log-rank P=0.017 (HR 1.46, 95%CI 1.05-2.03). In multivariate analysis including menopausal status, stage, and treatment arm, the type of endocrine therapy maintained a significant association with DFS (Table). In the subgroup of premenopausal patients, the use of GnRH was associated with numerically improved DFS: 86.6% vs 81.6%, log-rank P=0.168 (HR=0.70, 95%CI 0.43-1.16). Conclusions: In this post-hoc analysis of the ShortHER trial, adjuvant treatment with aromatase inhibitor was independently associated with improved DFS. Subgroup analysis in premenopausal patients suggests potential benefit with ovarian suppression. Clinical trial information: NCT00629278. [Table: see text]

A comprehensive profiling of the immune microenvironment of breast cancer brain metastases

BACKGROUND

Despite potential clinical implications, the complexity of breast cancer (BC) brain metastases (BM) immune microenvironment is poorly understood. Through multiplex immunofluorescence, we here describe the main features of BCBM immune microenvironment (density and spatial distribution) and evaluate its prognostic impact.

METHODS

Sixty BCBM from patients undergoing neurosurgery at three institutions (2003-2018) were comprehensively assessed using two multiplex immunofluorescence panels (CD4, CD8, Granzyme B, FoxP3, CD68, pan-cytokeratin, DAPI; CD3, PD-1, PD-L1, LAG-3, TIM-3, CD163, pan-cytokeratin, DAPI). The prognostic impact of immune subpopulations and cell-to-cell spatial interactions was evaluated.

RESULTS

Subtype-related differences in BCBM immune microenvironment and its prognostic impact were observed. While in HR-/HER2- BM and HER2+ BM, higher densities of intra-tumoral CD8+ lymphocytes were associated with significantly longer OS (HR 0.16 and 0.20, respectively), in HR+/HER2- BCBMs a higher CD4+FoxP3+/CD8+ cell ratio in the stroma was associated with worse OS (HR 5.4). Moreover, a higher density of intra-tumoral CD163+ M2-polarized microglia/macrophages in BCBMs was significantly associated with worse OS in HR-/HER2- and HR+/HER2- BCBMs (HR 6.56 and 4.68, respectively), but not in HER2+ BCBMs. In HER2+ BCBMs, multiplex immunofluorescence highlighted a negative prognostic role of PD-1/PD-L1 interaction: patients with a higher percentage of PD-L1+ cells spatially interacting with (within a 20 µm radius) PD-1+ cells presented a significantly worse OS (HR 4.60).

CONCLUSIONS

Our results highlight subtype-related differences in BCBM immune microenvironment and identify two potential therapeutic targets, M2 microglia/macrophage polarization in HER2- and PD-1/PD-L1 interaction in HER2+ BCBMs, which warrant future exploration in clinical trials.

HER2-low-positive breast cancer: evolution from primary tumor to residual disease after neoadjuvant treatment

Approximately a half of breast tumors classified as HER2-negative exhibit HER2-low-positive expression. We recently described a high instability of HER2-low-positive expression from primary breast cancer (BC) to relapse. Previous studies reporting discordance in HER2 status between baseline biopsy and residual disease (RD) in patients undergoing neoadjuvant treatment did not include the HER2-low-positive category. The aim of this study is to track the evolution of HER2-low-positive expression from primary BC to RD after neoadjuvant treatment. Patients undergoing neoadjuvant treatment with available baseline tumor tissue and matched samples of RD (in case of no pCR) were included. HER2-negative cases were sub-classified as HER2-0 or HER2-low-positive (IHC 1+ or 2+ and ISH negative). Four-hundred forty-six patients were included. Primary BC phenotype was: HR-positive/HER2-negative 23.5%, triple-negative (TN) 35%, HER2-positive 41.5%. HER2-low-positive cases were 55.6% of the HER2-negative cohort and were significantly enriched in the HR-positive/HER2-negative vs. TN subgroup (68.6% vs. 46.8%, p = 0.001 χ2 test). In all, 35.3% of non-pCR patients (n = 291) had a HER2-low-positive expression on RD. The overall rate of HER2 expression discordance was 26.4%, mostly driven by HER2-negative cases converting either from (14.8%) or to (8.9%) HER2-low-positive phenotype. Among HR-positive/HER2-negative patients with HER2-low-positive expression on RD, 32.0% and 57.1% had an estimated high risk of relapse according to the residual proliferative cancer burden and CPS-EG score, respectively. In conclusion, HER2-low-positive expression showed high instability from primary BC to RD after neoadjuvant treatment. HER2-low-positive expression on RD may guide personalized adjuvant treatment for high-risk patients in the context of clinical trials with novel anti-HER2 antibody-drug conjugates.

Major advancements in metastatic breast cancer treatment: when expanding options means prolonging survival

In the last years we have witnessed tremendous advancements in the treatment landscape of metastatic breast cancer (MBC), leading to a progressive prolongation of progression-free survival and, in some cases, also of overall survival. This led to a substantial increase of advanced disease treatability. In the present review we comprehensively and critically describe the most significant progresses in the therapeutic scenario of MBC according to BC subtype. In particular, we reviewed studies reporting practice-changing data in hormone receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative, HER2-positive and triple-negative BC, with also a hint to BRCA-related tumors and the emerging HER2-low-positive category.

Survival after neoadjuvant therapy with trastuzumab-lapatinib and chemotherapy in patients with HER2-positive early breast cancer: a meta-analysis of randomized trials

BACKGROUND

Studies testing the addition of lapatinib to neoadjuvant trastuzumab + chemotherapy reported an increase in pathologic complete response (pCR), with, nevertheless, discordant results in terms of survival, mainly due to suboptimal power. We here leverage the meta-analytic approach to resolve these inconsistencies.

METHODS

We conducted a meta-analysis of randomized phase II/III studies testing lapatinib + trastuzumab in combination with neoadjuvant chemotherapy for human epidermal growth factor receptor (HER2)-positive early breast cancer (BC). Recurrence-free survival (RFS) and overall survival (OS) were adopted as survival endpoints. Pooled hazard ratios (HR) were obtained for the effect of lapatinib + trastuzumab versus trastuzumab, pCR versus no-pCR in the whole study populations and pCR versus no-pCR according to hormone receptor status.

RESULTS

Four phase II/III randomized trials were included in the meta-analysis (CALGB 40601, Cher-LOB, NSABP-B41, NeoALTTO) for an overall population of 1410 patients receiving neoadjuvant chemotherapy in association with either trastuzumab, lapatinib or their combination. RFS was significantly improved with dual HER2 blockade as compared to trastuzumab [HR 0.62, 95% confidence interval (CI) 0.46-0.85]. Dual blockade also led to significantly improved OS (HR 0.65, 95% CI 0.43-0.98). For all treatments combined, patients achieving pCR had better RFS and OS than those with residual disease (HR 0.45, 95% CI 0.34-0.60, and HR 0.32, 95% CI 0.22-0.48, for RFS and OS, respectively). In patients with hormone receptor-negative tumors, pCR was associated with 65% and 73% relative reduction of risk of relapse and death, respectively. Patients with hormone receptor-positive tumors also experienced improved RFS if they achieved pCR; however, the benefit was smaller than that in hormone receptor-negative disease.

CONCLUSION

Findings from this meta-analysis further validate the role of pCR as a strong predictor of outcome in patients with HER2-positive BC, especially in hormone receptor-negative disease. Moreover, we provide robust evidence that dual blockade with lapatinib + trastuzumab in combination with neoadjuvant chemotherapy prolongs OS, suggesting that the role of lapatinib could be reconsidered in the early setting.

Clinical profile and mortality of Sars-Cov-2 infection in cancer patients across two pandemic time periods (Feb 2020-Sep 2020; Sep2020- May 2021) in the Veneto Oncology Network: the ROVID study

Introduction

We analyzed a cohort of patients with cancer and Sars-Cov-2 infection from the Veneto Oncology Network registry across two pandemic time periods.

Materials and methods

761 patients with cancer and SARS-CoV-2 infection were included.

Results

198 patients were diagnosed during the first pandemic time period (TP1; February 2020 September 2020), 494 during TP2 before the vaccination campaign (TP2/pre-vaccination; September 2020-21 February 2021) and 69 in TP2/post-vaccination (22 February 2021-15 May 2021). TP2 vs TP1 patients were younger (p = 0.004), showed more frequently a good performance status (p < 0.001) and <2 comorbidities (p = 0.002), were more likely to be on active anticancer therapy (p = 0.006). Significantly fewer patients in TP2 (3-4%) vs TP1 (22%) had an in-hospital potential source of infection (p < 0.001). TP2 patients were more frequently asymptomatic (p = 0.003). Significantly fewer patients from TP2 were hospitalized (p < 0.001) or admitted to intensive care unit (p = 0.006). All-cause mortality decreased from 30.3% in TP1, to 8.9% and 8.7% in the two TP2 periods (p < 0.001), reflected by a significant reduction in Sars-Cov-2-related mortality (15.2%, 7.5% and 5.8% in the three consecutive time periods, p = 0.004).

Conclusions

Differences in clinical characteristics and features of Sars-Cov-2 infection between TP1 and TP2 reflect the effects of protective measures and increased testing capacity. The lower mortality in TP2 is in line with a less frail population. However, the vast majority of death events in TP2 were related to COVID-19, reinforcing the priority to protect cancer patients.

Abstract P2-12-04: Characterization of gut microbiome composition in triple negative breast cancer patients treated with neoadjuvant chemotherapy

Background: Recent evidences showed intestinal microbiota to be implicated in carcinogenesis and response to chemotherapy and immune checkpoint inhibitors in solid tumors. Furthermore, antibiotics are known to deeply influence microbiome composition in healthy people and cancer patients. The role of gut microbiome in triple negative breast cancer (TNBC) is underexplored. Methods: In this pilot prospective study, we characterized the gut microbiome of 30 TNBC patients undergoing neoadjuvant chemotherapy at two Italian Institutions. Fecal samples were collected at 2 timepoints: at the baseline (t0) and at 1 week (t1) from CT. Microbiome was analyzed by 16S rRNA sequencing. Measures of α-diversity expressed by Richness and Simpson evenness were evaluated at the species level. β-diversity was calculated using PERMANOVA test according to UniFrac measures of dissimilarity at the species level.Tumor infiltrating lymphocytes (TILs) were assessed from diagnostic core biopsy and surgical specimen. Results: From September 2017 to March 2020, 30 TNBC patients were enrolled. Median age was 53 years, 43% were premenopausal, 43% were overweight or obese (BMI&gt;25); 97% had a histologic G3 carcinoma, clinical nodal involvements was present in 57%; median TILs at diagnosis was 30%. All patients received anthracycline and taxane-based chemotherapy, including carboplatin in 23 patients (77%). A pCR was achieved in 15 (50%) patients. The overall rate of stool samples collection was 93%. With regards to t0, no differences in terms of α- and β-diversity were found.At t1, α-diversity was significantly higher in pCR group (Simpson evenness index, p=0.016). Considering clinical-pathological features, a BMI &lt;24.9 was associated with higher microbiome richness (p=0.012). Measurements of β-diversity did not differ between groups.As 73% of patients during the treatment phase received antibiotics, with consequent potential microbiome impairment, we repeated analyses at t1 considering fecal samples collected &gt;90 days after the end of antibiotic therapy (N=17). At this analysis, β-diversity evaluated with Unifrac measure was significantly correlated with pCR (p=0.035), with Haemophilus Influentiae being significantly enriched in non-pCR group. Conclusions: Fecal microbiome collection and analysis in this population is feasible and deserves further investigation with regards its association with response to chemotherapy.

Citation Format: Grazia Maria Vernaci, Davide Massa, Ilaria Patuzzi, Alice Menichetti, Tommaso Giarratano, Gaia Griguolo, Federica Miglietta, Matteo Fassan, Edoardo Savarino, PierFranco Conte, Valentina Guarneri, Maria Vittoria Dieci. Characterization of gut microbiome composition in triple negative breast cancer patients treated with neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-12-04.

Abstract PD5-06: Safety of assisted reproductive technologies (ART) following treatment completion in young women with germline BRCA pathogenic variants having a pregnancy after breast cancer

BACKGROUND: Young breast cancer (BC) survivors are at risk of infertility. Ovarian stimulation for fertility preservation before (neo)adjuvant chemotherapy is standard of care. Research efforts have shown no negative prognostic effect of pregnancy following BC therapy, also among BRCA carriers. Currently, poor evidence is available on the safety to undergo ART following BC treatment, with no data in carriers of germline BRCA pathogenic variants. To provide evidence on the safety of fertility treatments in this specific population, we assessed the outcomes of a cohort of BRCA-mutated BC survivors who had a pregnancy after prior BC history by comparing the group of patients who underwent ART to achieve pregnancy to the group with spontaneous pregnancy. METHODS: We conducted a multicenter retrospective cohort study across 30 centers worldwide including women diagnosed at ≤ 40 years with stage I-III BC, between January 2000 and December 2012, bearing germline BRCA1/2 pathogenic variants. Survivors with a pregnancy (any outcome) after BC, with no disease-free survival (DFS) event before pregnancy, were assigned to the ART and non-ART group if their pregnancy was achieved through ART or spontaneously, respectively. ART procedures included ovulation induction, ovarian stimulation for in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), and embryo transfer under hormonal replacement therapy (HRT). RESULTS: Of 1,424 patients registered in the study, 168 with a pregnancy after BC were included in the present analysis. A total of 22 patients were included in the ART group and 146 in the non-ART group. Before BC diagnosis, 18.2% patients in the ART group had at least one child, compared to 38.4% in the non-ART group (P=0.030). Patients had a median age at BC diagnosis of 33.0 vs 30.2 years old in the ART group and in the non-ART group, respectively (P=0.004); 45.4% and 17.1% had grade 1-2 tumors, respectively (P=0.008), and 59.1% vs 31.5% had hormone receptor-positive tumors, respectively (P=0.016). Both cohorts had similar tumor size and nodal stage characteristics. Type and duration of endocrine therapy were comparable between groups. The type of ART was not specified in 5 survivors (22.7%). Ovulation induction was used in 1 patient (4.5%), ovarian stimulation in 7 patients (31.8%), embryo transfer under HRT following oocyte donation in 5 patients (22.7%), and embryo transfer under HRT following oocyte and/or embryo cryopreservation for fertility preservation in 4 patients (18.2%). Median age at conception among survivors was 39.7 years in the ART group versus 35.4 years in the non-ART group (P&lt;0.001). Overall, no differences in obstetrical outcomes were observed between groups, although there were more delivery complications in the ART group vs the non-ART group (22.1% vs 4.1%, respectively, P=0.011). Median follow-up from pregnancy was 3.4 years (range: 0.8-8.6) for patients in the ART group vs 5.0 years (range: 0.8-17.6) in the non-ART group (P=0.009). In the ART group, 2 patients (9.1%) experienced a DFS event (both were loco-regional recurrences) as compared to 40 patients (27.4%) in the non-ART group (P=0.182). No patients died in the ART group compared to 10 patients (6.9%) in the non-ART group. CONCLUSIONS: To our knowledge, this is the first study assessing the safety of ART in BC survivors bearing germline BRCA pathogenic variants. Even though the exposed cohort was small, results showed that the use of ART does not appear to increase the relapse risk at short-term follow-up. Further reproductive studies in BRCA-mutated BC patients are warranted.

Citation Format: Margherita Condorelli, Marco Bruzzone, Marcello Ceppi, Alberta Ferrari, Albert Grinshpun, Anne-Sophie Hamy, Evandro de Azambuja, Estela Carrasco, Fedro A. Peccatori, Antonio Di Meglio, Shani Paluch-Shimon, Philip D. Poorvu, Marta Venturelli, Christine Rousset-Jablonski, Claire Senechal, Luca Livraghi, Riccardo Ponzone, Laura De Marchis, Katarzyna Pogoda, Amir Sonnenblick, Cynthia Villarreal-Garza, Octavi Córdoba, Luis Teixeira, Florian Clatot, Kevin Punie, Rossella Graffeo Galbiati, Maria Vittoria Dieci, Alejandro Pérez-Fidalgo, Francois P. Duhoux, Fabio Puglisi, Arlindo R. Ferreira, Eva Blondeaux, Tamar Peretz-Yablonski, Olivier Caron, Claire Saule, Lieveke Ameye, Judith Balmaña, Ann H. Partridge, Hatem A. Azim, Jr, Isabelle Demeestere, Matteo Lambertini. Safety of assisted reproductive technologies (ART) following treatment completion in young women with germline BRCA pathogenic variants having a pregnancy after breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD5-06.

Abstract PD4-01: Response according to revised RANO criteria is associated with overall survival in breast cancer patients with leptomeningeal metastasis

Introduction: Leptomeningeal metastasis (LM) is a severe complication of many solid tumors generally associated with dismal prognosis. Limited therapeutic options are available in this setting and assessment of response to treatment currently lacks validated tools. In 2017, the Response Assessment in Neuro-Oncology (RANO) LM Working Group proposed a standardized scorecard to aid in the evaluation of MRI findings in LM, which was revised and simplified in a subsequent 2019 version. To date, the prognostic impact of response to treatment evaluated according to these criteria has not been assessed in breast cancer (BC). In this study, we aim to validate this tool in a multicentric cohort of BC patients (pts) diagnosed with LM.Methods: Pts with LM from BC diagnosed at Istituto Oncologico Veneto (Padova, Italy) and Montpellier Regional Cancer Institute (Montpellier, France) between December 2005 and June 2018 were identified. Clinicopathological characteristics were collected from medical charts. Baseline and follow-up MRI scans were centrally reviewed by a dedicated radiologist and response assessment was evaluated according to the 2019 revised RANO LM response criteria (Le Rhun E. et al., Neuro-Oncology 2019).Results: A total of 225 pts diagnosed with BC-related LM were identified; among these, 142 had an available baseline brain MRI imaging and were included in the present study. Among these 142 pts, 78 had a positive cerebrospinal fluid (CSF) cytology and were classified as type I according to EANO-ESMO classification (41 type IA, 9 type IB, 28 type IC); for 64 pts CSF cytology was negative (N=25) or not performed (N=39), and were classified as type II (28 type IIA, 4 type IIB, 32 type IIC). At the time of last follow-up, 138 out of 142 pts had died and median overall survival (OS) from baseline MRI was 5.0 months (95% CI 3.4-6.7). Presence/absence of positive CSF cytology did not impact OS (median OS 5.3 versus 5.2 months, log-rank p=0.406). A total of 60 pts (positive/negative/not done CSF cytology: N=36/9/15) had an evaluable follow-up MRI imaging, with drop-off mainly due to deteriorating performance status or death. In this selected subgroup of pts, a longer OS was observed (median OS 15.2 months; 95% CI 9.5-21.0). Treatment administered for BC-related LM was heterogeneous and several pts received more than one treatment modality: systemic chemotherapy (N=44), endocrine therapy (N=27), HER2-targeted treatment (N=16), intrathecal chemotherapy (N=37) and radiotherapy (N=24). Response to treatment at time of first disease re-evaluation by brain MRI imaging was as follows: complete response for 2 pts, partial response for 12 pts, stable disease for 33 pts, and progression of disease for 13 pts. Response according to 2019 RANO criteria was significantly associated with OS (p=0.029, Table 1). Conclusions: Response assessment in pts with LM is challenging. In our study, the 2019 RANO revised response score was associated with OS in patients with LM from BC, thus validating these criteria in a real-world cohort.

Response according to 2019 RANO LM criteriaMedian OS (months)OS 95% CI (months)Univariate Cox Hazard RatioUnivariate Cox Hazard Ratio 95% CIp-valueComplete Response31.1NE-NE0.100.01-0.780.028Partial Response16.10.0-37.40.410.17-0.970.043Stable Disease17.98.3-27.50.450.22-0.910.026Progression of Disease9.55.9-13.1Ref.Ref.Ref.

Citation Format: Gaia Griguolo, Vittoria Aldegheri, Michele Bottosso, Francesca Caumo, Stéphane Pouderoux, Federica Miglietta, William Jacot, Maria Vittoria Dieci, Amélie Darlix, Valentina Guarneri. Response according to revised RANO criteria is associated with overall survival in breast cancer patients with leptomeningeal metastasis [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD4-01.

Neoadjuvant Chemotherapy and Immunotherapy in Luminal B-like Breast Cancer: Results of the Phase II GIADA Trial

PURPOSE

The role of immunotherapy in hormone receptor (HR)-positive, HER2-negative breast cancer is underexplored.

PATIENTS AND METHODS

The neoadjuvant phase II GIADA trial (NCT04659551, EUDRACT 2016-004665-10) enrolled stage II-IIIA premenopausal patients with Luminal B (LumB)-like breast cancer (HR-positive/HER2-negative, Ki67 ≥ 20%, and/or histologic grade 3). Patients received: three 21-day cycles of epirubicin/cyclophosphamide followed by eight 14-day cycles of nivolumab, triptorelin started concomitantly to chemotherapy, and exemestane started concomitantly to nivolumab. Primary endpoint was pathologic complete response (pCR; ypT0/is, ypN0).

RESULTS

A pCR was achieved by 7/43 patients [16.3%; 95% confidence interval (CI), 7.4-34.9]; the rate of residual cancer burden class 0-I was 25.6%. pCR rate was significantly higher for patients with PAM50 Basal breast cancer (4/8, 50%) as compared with other subtypes (LumA 9.1%; LumB 8.3%; P = 0.017). Tumor-infiltrating lymphocytes (TIL), immune-related gene-expression signatures, and specific immune cell subpopulations by multiplex immunofluorescence were significantly associated with pCR. A combined score of Basal subtype and TILs had an AUC of 0.95 (95% CI, 0.89-1.00) for pCR prediction. According to multiplex immunofluorescence, a switch to a more immune-activated tumor microenvironment occurred following exposure to anthracyclines. Most common grade ≥3 treatment-related adverse events (AE) during nivolumab were γ-glutamyltransferase (16.7%), alanine aminotransferase (16.7%), and aspartate aminotransferase (9.5%) increase. Most common immune-related AEs were endocrinopathies (all grades 1-2; including adrenal insufficiency, n = 1).

CONCLUSIONS

Luminal B-like breast cancers with a Basal molecular subtype and/or a state of immune activation may respond to sequential anthracyclines and anti-PD-1. Our data generate hypotheses that, if validated, could guide immunotherapy development in this context.

Development and validation of the new HER2DX assay for predicting pathological response and survival outcome in early-stage HER2-positive breast cancer

Background

Both clinical and genomic data independently predict survival and treatment response in early-stage HER2-positive breast cancer. Here we present the development and validation of a new HER2DX risk score, and a new HER2DX pathological complete response (pCR) score, both based on a 27-gene expression plus clinical feature-based classifier.

Methods

HER2DX is a supervised learning algorithm incorporating tumour size, nodal staging, and 4 gene expression signatures tracking immune infiltration, tumour cell proliferation, luminal differentiation, and the expression of the HER2 amplicon, into a single score. 434 HER2-positive tumours from the Short-HER trial were used to train a prognostic risk model; 268 cases from an independent cohort were used to verify the accuracy of the HER2DX risk score. In addition, 116 cases treated with neoadjuvant anti-HER2-based chemotherapy were used to train a predictive model of pathological complete response (pCR); two independent cohorts of 91 and 67 cases were used to verify the accuracy of the HER2DX pCR likelihood score. Five publicly available independent datasets with >1,000 patients with early-stage HER2-positive disease were also analysed.

Findings

In Short-HER, HER2DX variables were associated with good risk outcomes (i.e., immune, and luminal) and poor risk outcomes (i.e., proliferation, and tumour and nodal staging). In an independent cohort, continuous HER2DX risk score was significantly associated with disease-free survival (DFS) (p=0·002); the 5-year DFS in the low-risk group was 97·4% (94·4-100·0%). For the neoadjuvant pCR predictor training cohort, HER2DX variables were associated with pCR (i.e., immune, proliferation and HER2 amplicon) and non-pCR (i.e., luminal, and tumour and nodal staging). In both independent test set cohorts, continuous HER2DX pCR likelihood score was significantly associated with pCR (p<0·0001). A weak negative correlation was found between the HER2DX risk score versus the pCR score (correlation coefficient -0·19).

Interpretation

The two HER2DX tests provide accurate estimates of the risk of recurrence, and the likelihood to achieve a pCR, in early-stage HER2-positive breast cancer.

Funding

This study received funding from Reveal Genomics, IDIBAPS and the University of Padova.

Gene-expression signatures to inform neoadjuvant treatment decision in HR+/HER2- breast cancer: Available evidence and clinical implications

Over the last few years, the indication for chemotherapy use in HR+/HER2- early BC has been significantly modified by the introduction of gene-expression profiling. In the adjuvant setting, several gene-expression signatures have been validated to discriminate early stage HR+/HER2- BC with different prognosis and to identify patients for which adjuvant chemotherapy can be spared. Considering their ability to optimize the choice of adjuvant treatment and the increasing use of neoadjuvant approach in early BC, the potential use of gene-expression signatures to discriminate patients to be candidate to neoadjuvant chemotherapy or endocrine treatment appears particularly appealing. Indeed, the San Gallen Consensus Conference panel recently endorsed the use of genomic assays on core biopsies as a potential strategy for choosing the type of neoadjuvant treatment (chemotherapy or endocrine therapy) in selected patients. In this context, we here review evidence supporting the use of most common commercially available gene-expression signatures (Oncotype DX, MammaPrint, PAM50, EndoPredict and Breast Cancer Index) in patients receiving neoadjuvant therapy for HR+/HER2- BC. Data on the association of gene expression signatures and response to neoadjuvant chemotherapy or neoadjuvant endocrine therapy will be reviewed and the clinical implications of this data to guide the clinical decision-making process in early HR+/HER2- BC will be discussed.

The tale of TILs in breast cancer: A report from The International Immuno-Oncology Biomarker Working Group

The advent of immune-checkpoint inhibitors (ICI) in modern oncology has significantly improved survival in several cancer settings. A subgroup of women with breast cancer (BC) has immunogenic infiltration of lymphocytes with expression of programmed death-ligand 1 (PD-L1). These patients may potentially benefit from ICI targeting the programmed death 1 (PD-1)/PD-L1 signaling axis. The use of tumor-infiltrating lymphocytes (TILs) as predictive and prognostic biomarkers has been under intense examination. Emerging data suggest that TILs are associated with response to both cytotoxic treatments and immunotherapy, particularly for patients with triple-negative BC. In this review from The International Immuno-Oncology Biomarker Working Group, we discuss (a) the biological understanding of TILs, (b) their analytical and clinical validity and efforts toward the clinical utility in BC, and (c) the current status of PD-L1 and TIL testing across different continents, including experiences from low-to-middle-income countries, incorporating also the view of a patient advocate. This information will help set the stage for future approaches to optimize the understanding and clinical utilization of TIL analysis in patients with BC.