Adjuvant treatment in hormone receptor-positive early breast cancer: New approaches of endocrine therapy

Breast cancer is the most common cancer in women, and luminal breast cancer is the predominant subtype, characterized by the presence of estrogen receptors and/or progesterone receptors in tumor cells. Adjuvant endocrine therapy is the pivotal approach in the management of luminal early breast cancer. Hence, new therapeutic approaches have been studied during the last few years, especially in patients with high risk of recurrence.Here we provide a summary of the most recent clinical trials evaluating adjuvant treatment in hormone-receptors-positive early breast cancer. First, the main cornerstone is related to the role of extended endocrine treatment, which has been widely investigated to access a benefit in disease-free survival and overall survival (only the GIM4 trial has positive feedback about survival) and to tailor the treatment according to patient compliance. The results highlighted an advantage in extending the use of endocrine treatment for at least seven full years, considering aromatase inhibitors as principal drugs. Second, the shift of CDK4/6 inhibitors (CDK4/6i) from advanced to early setting reported positive outcomes, with favorable results from MonarchE and NATALEE trials, using Abemaciclib and Ribociclib respectively, even if non-negligible toxicities have been reported. Last, the use of PARP inhibitors for BRCA1/2 mutated patients has been evaluated in the OlympiA trial (Olaparib), observing a comparable benefit between hormone-receptors-positive and triple-negative early breast cancer.However, more data are still required to better select patients that could benefit more from CDK4/6i considering side effects too, and sequential treatments are still not codified.

Fine-Tuning Adjuvant Endocrine Therapy for Early-Stage Breast Cancer: An Expert Consensus on Open Issues for Future Research

After decades of research, improving the efficacy of adjuvant endocrine therapy (ET) for early-stage breast cancer becomes increasingly difficult. Beyond technological breakthroughs and the availability of new classes of drugs, further improvement of adjuvant ET will require applying a rigorous research approach in poorly investigated areas. We critically discuss some key principles that should inform future research to improve ET efficacy, including identifying specific subgroups of patients who can benefit from escalating or de-escalating approaches, optimizing available and new treatment strategies for different clinical contexts, and dissecting the direct and indirect biological effects of therapeutic interventions. Four main issues regarding adjuvant ET were identified as relevant areas, where a better application of such principles can provide positive results in the near future: (i) tailoring the optimal duration of adjuvant ET, (ii) optimizing ovarian function suppression for premenopausal women, (iii) dissecting the biological effects of estrogen receptor manipulation, and (iv) refining the selection of patients to candidate for treatments escalation.

Rare Breast Cancer Histotypes-A Retrospective Study and Literature Review

Breast cancer is the most common cancer among women globally and can be classified according to various histological subtypes. Current treatment strategies are typically based on the cancer stage and molecular subtypes. This article aims to address the knowledge gap in the understanding of rare breast cancer. A retrospective study was conducted on 4393 breast cancer patients diagnosed from 1992 to 2012, focusing on five rare subtypes: mucinous, invasive lobular, papillary, mixed invasive and lobular, and pure tubular/cribriform carcinomas. Our analysis, supplemented by a literature review, compared patient characteristics, disease characteristics, and survival outcomes of rare breast cancer patients with invasive carcinoma (not otherwise specified (NOS)). Comparative analysis revealed no significant difference in overall survival rates between these rare cancers and the more common invasive carcinoma (NOS). However, mucinous, papillary, and tubular/cribriform carcinomas demonstrated better disease-specific survival. These subtypes presented with similar characteristics such as early detection, less nodal involvement, more hormonal receptor positivity, and less human epidermal growth factor receptor 2 (HER2) positivity. To conclude, our study demonstrated the diversity in the characteristics and prognosis of rare breast cancer histotypes. Future research should be carried out to investigate histotype-specific management and targeted therapies, given their distinct behavior.

Effect of histological breast cancer subtypes invasive lobular versus non-special type on survival in early intermediate-to-high-risk breast carcinoma: results from the SUCCESS trials

BACKGROUND

Invasive lobular breast carcinomas (ILC) have different histological features compared to non-special type carcinomas (NST), but the effect of histological subtypes on survival is controversial. In this study, we compared clinicopathological characteristics and outcomes between ILC and NST based on a large pooled data set from three adjuvant breast cancer trials (SUCCESS A, B, and C) and investigated a potential differential effect of recurrence risk related to nodal stage on survival.

METHODS

From 2005 to 2017, the large randomized controlled SUCCESS A, B, and C trials enrolled 8190 patients with primary, intermediate-to-high-risk breast carcinoma. All patients received adjuvant chemotherapy, and endocrine and/or HER2-targeted treatment was given where appropriate. Survival outcomes in terms of disease-free survival (DFS), overall survival (OS), breast cancer-specific survival (BCSS), and distant disease-free survival (DDFS) were estimated using the Kaplan-Meier method and analyzed using log-rank tests as well as univariable and adjusted multivariable Cox regression models.

RESULTS

In the SUCCESS trials, 6284 patients had NST and 952 had ILC. The median follow-up time was 64 months. ILC patients were older, more likely to receive mastectomy, and more likely to have larger tumor sizes, lymph node infiltration, hormone receptor-positive, HER2neu-negative, and luminal A-like tumors than NST patients. In the overall cohort, no significant differences between ILC and NST were detectable regarding the four survival endpoints, with hazard ratios obtained in adjusted multivariable cox regressions of 0.96 (95% CI 0.77-1.21, p = 0.743) for DFS, 1.13 (95% CI 0.85-1.50, p = 0.414) for OS, 1.21 (95% CI 0.89-1.66, p = 0.229) for BCSS, and 0.95 (95% CI 0.73-1.24, p = 0.689) for DDFS. However, a differential effect of nodal stage on survival was observed, with better survival for ILC patients with pN0/pN1 tumors and worse survival for ILC patients with pN2/pN3 tumors compared to NST patients.

CONCLUSIONS

Our results revealed that ILC was associated with worse survival compared to NST for patients at high risk of recurrence due to advanced lymph node infiltration. These findings should be taken into account for treatment decisions and monitoring.

Hypoxia: syndicating triple negative breast cancer against various therapeutic regimens

Triple-negative breast cancer (TNBC) is one of the deadliest subtypes of breast cancer (BC) for its high aggressiveness, heterogeneity, and hypoxic nature. Based on biological and clinical observations the TNBC related mortality is very high worldwide. Emerging studies have clearly demonstrated that hypoxia regulates the critical metabolic, developmental, and survival pathways in TNBC, which include glycolysis and angiogenesis. Alterations to these pathways accelerate the cancer stem cells (CSCs) enrichment and immune escape, which further lead to tumor invasion, migration, and metastasis. Beside this, hypoxia also manipulates the epigenetic plasticity and DNA damage response (DDR) to syndicate TNBC survival and its progression. Hypoxia fundamentally creates the low oxygen condition responsible for the alteration in Hypoxia-Inducible Factor-1alpha (HIF-1α) signaling within the tumor microenvironment, allowing tumors to survive and making them resistant to various therapies. Therefore, there is an urgent need for society to establish target-based therapies that overcome the resistance and limitations of the current treatment plan for TNBC. In this review article, we have thoroughly discussed the plausible significance of HIF-1α as a target in various therapeutic regimens such as chemotherapy, radiotherapy, immunotherapy, anti-angiogenic therapy, adjuvant therapy photodynamic therapy, adoptive cell therapy, combination therapies, antibody drug conjugates and cancer vaccines. Further, we also reviewed here the intrinsic mechanism and existing issues in targeting HIF-1α while improvising the current therapeutic strategies. This review highlights and discusses the future perspectives and the major alternatives to overcome TNBC resistance by targeting hypoxia-induced signaling.

Treatment and outcome in metastatic lobular breast cancer in the prospective German research platform OPAL

PURPOSE

Evidence about routine treatment and outcome of patients with invasive lobular cancer (ILC) is limited, especially regarding metastatic disease. Here we present prospective real-world data of patients with metastatic ILC (mILC) as compared to patients with metastatic invasive ductal cancer (mIDC) receiving systemic therapy in routine care in Germany.

METHODS

Prospective data on patient and tumor characteristics, treatments, and outcomes of patients with mILC (n = 466) and mIDC (n = 2100), recruited between 2007 and 2021 into the Tumor Registry Breast Cancer/OPAL were analyzed.

RESULTS

Compared to mIDCs, patients with mILC were older at start of first-line treatment (median 69 vs. 63 years) and had more often lower grade (G1/G2: 72.8% vs. 51.2%), hormone receptor (HR)-positive (83.7% vs. 73.2%) and less often HER2-positive (14.2% vs. 28.6%) tumors, which metastasized more frequently to the bone (19.7% vs. 14.5%) or peritoneum (9.9% vs. 2.0%), and less frequently to the lungs (0.9% vs. 4.0%). Median OS of patients with mILC (n = 209) and mIDC (n = 1158) was 30.2 months [95% confidence interval (CI) 25.3, 36.0] and 33.7 months [95% CI 30.3, 37.9], respectively. Multivariate survival analysis did not show a significant prognostic impact of the histological subtype [HR mILC vs. mIDC 1.18 (95% CI 0.97-1.42)].

CONCLUSION

Overall, our real-world data confirm clinicopathological differences between mILC and mIDC breast cancer patients. Despite patients with mILC presenting with some favorable prognostic factors, ILC histopathology was not associated with a better clinical outcome in multivariate analysis, suggesting the need for more tailored treatment strategies for patients with the lobular subtype.

Pure Mucinous Carcinoma of the Breast: Radiologic-Pathologic Correlation

Mucinous carcinoma (MC) of the breast is a rare, specialized subtype of invasive breast carcinoma (IBC) accounting for approximately 1% to 4% of all primary breast malignancies. Mucinous carcinoma occurs predominantly in patients who are postmenopausal or elderly. It is usually detected on screening mammography, but occasionally the patient may present with a palpable mass. The most common mammographic appearance is an equal to high density, oval or round mass with circumscribed or indistinct margins; MC can mimic a benign lesion. Histologically, MC is a well-differentiated cancer characterized by pools of mucin around neoplastic cells. Depending on mucin content, the tumor is classified as pure (≥90% mucin) or mixed (>10% and <90% mucin). Pure MCs (PMCs) are of low or intermediate nuclear grade, and the vast majority are hormone receptor-positive and human epidermal growth factor-2 receptor-negative (luminal A subtype). Pure MCs may be classified as hypocellular (type A) or hypercellular (type B) and have a lower rate of axillary lymph node involvement and more favorable prognosis than IBCs, no special type. The purpose of this article is to review the clinical features, imaging appearances, associated histopathology, and management of PMC.

Prognostic value of complex glandular patterns in invasive pulmonary adenocarcinomas

Prognostic stratification of patients surgically resected with invasive pulmonary adenocarcinoma must be improved. Previous studies reported that complex glandular patterns (CGPs), cribriform and fused gland growth patterns, are associated with unfavorable prognosis. The goal of this study is to evaluate the prognostic value of CGPs in patients with resected stage I-IV lung adenocarcinoma. The presence of CGPs as a minor to predominant component was tested for association with overall survival (OS, n=676) and relapse-free survival (RFS, n=463) after surgery. CGPs were observed in 284 (42.0%) tumors. Cribriform and fused gland were the predominant patterns in 35 and 37 cases, respectively. The presence of cribriform pattern was associated with worse RFS, but not OS. The fused gland pattern alone or grouped into CGPs with the cribriform pattern was not associated with OS and RFS. As predominant pattern, cribriform was associated with the worse survival compared to the five recognized histologic patterns. Patients with fused gland-predominant tumors had 5-year survival that ranged between papillary- and micropapillary-predominant tumors. We conclude that cribriform-predominant, but not fused gland-predominant, is a subtype with poor prognosis similar to the solid and micropapillary subtypes. In contrast, the presence of a minor component of fused gland or CGPs (cribriform + fused gland) is not associated with survival. The cribriform pattern alone offers prognosis stratification improvement, but this effect is attenuated when combined into CGPs to define a subset of acinar-predominant tumors with poor prognosis. This argue against combining cribriform and fused gland into CGPs to summarise high-grade patterns.

Impact of lobular versus ductal histology on overall survival in metastatic breast cancer: a French retrospective multicentre cohort study

BACKGROUND

The impact of the histological lobular subtype on overall survival (OS) in metastatic breast cancer (MBC) is still under debate, with very few data available.

PATIENTS AND METHODS

Using the French national multicentre Epidemiological Strategy and Medico Economics [ESME]) data platform, the primary objective was to compare the OS of patients with invasive lobular carcinoma (ILC) versus invasive ductal carcinoma (IDC) MBC, with adjustment on the main prognostic factors using two approaches: multivariable analysis and matching with a propensity score. Secondary objectives were to compare first-line progression-free survival (PFS1) and describe patients and tumour characteristics.

RESULTS

Of the 16,703 patients with MBC in the ESME database, 13,111 met all inclusion criteria for the present analysis. One-thousand eight-hundred and four (13.8%) patients had ILC and 11.307 (86.2%) IDC. In the multivariable analysis, patients with ILC had a worse OS [hazard ratio (HR): 1.31; 95%CI 1.20-1.42; p < 0.0001] and a worse PFS1 (HR: 1.15; 95%CI 1.07-1.22; p < 0.0001) as compared with those with IDC, independently of hormone receptor and HER2 status. Interestingly, OS was better (HR 0.79; 95% confidence interval [CI] 0.64-0.98; p = 0.0302), worse (HR: 1.17; 95%CI 1.08-1.27; p = 0.0001) or similar (HR: 0.88; 95%CI 0.67-1.15; p = 0.3455) in patients with ILC with triple-negative, hormone receptor-positive/HER2-negative and HER2-positive MBC, respectively, compared with patients with IDC.

CONCLUSION

Lobular histology is an independent adverse prognostic factor among women with MBC. ILC MBC could be considered a specific entity. Dedicated prospective studies are needed to tailor the management of these patients.

How we treat HR-positive, HER2-negative early breast cancer

The present goal of therapy for early hormone receptor-positive (HR+)/human EGF receptor 2-negative (HER2-) BC is to optimize disease-free survival (DFS) and overall survival (OS) rates with the currently available therapies while avoiding any relevant long-term sequalae. Local therapies have evolved toward less aggressive techniques (i.e. breast-preserving surgery, sentinel lymph node biopsy and intraoperative radiotherapy), which significantly reduce the long-term sequalae observed with more radical treatments. Endocrine therapy (ET) is still the cornerstone of adjuvant treatment because it significantly reduces BC relapse and mortality. Adjuvant chemotherapy is today recommended only for a particular subset of patients with a high risk of recurrence with ET alone, identified through genomic assays, age and/or disease stage. Bisphosphonates reduce the risk of bone metastasis and produce a slight although statistically significant improvement in survival in postmenopausal women. The CDK 4/6 inhibitor abemaciclib has been recently approved by the US FDA for patients at high risk of relapse.

Mediator of DNA Damage Checkpoint 1 (MDC1) Is a Novel Estrogen Receptor Coregulator in Invasive Lobular Carcinoma of the Breast

Invasive lobular carcinoma (ILC) is the most common special histologic subtype of breast cancer, and nearly all ILC tumors express estrogen receptor alpha (ER). However, clinical and laboratory data suggest ILC are strongly estrogen-driven but not equally antiestrogen-sensitive. We hypothesized ILC-specific ER coregulators mediate ER functions and antiestrogen resistance in ILC, and profiled ER-associated proteins by mass spectrometry. Three ER+ ILC cell lines (MDA MB 134VI, SUM44PE, and BCK4) were compared with ER+ invasive ductal carcinoma (IDC) line data, and we examined whether siRNA of identified proteins suppressed ER-driven proliferation in ILC cells. This identified mediator of DNA damage checkpoint 1 (MDC1), a tumor suppressor in DNA damage response (DDR), as a novel ER coregulator in ILC. We confirmed ER:MDC1 interaction was specific to ILC versus IDC cells, and found MDC1 knockdown suppressed ILC cell proliferation and tamoxifen resistance. Using RNA-sequencing, we found in ILC cells MDC1 knockdown broadly dysregulates the ER transcriptome, with ER:MDC1 target genes enriched for promoter hormone response elements. Importantly, our data are inconsistent with MDC1 tumor suppressor functions in DDR, but suggest a novel oncogenic role for MDC1 as an ER coregulator. Supporting this, in breast tumor tissue microarrays, MDC1 protein was frequently low or absent in IDC, but MDC1 loss was rare in ER+ ILC. ER:MDC1 interaction and MDC1 coregulator functions may underlie ER function in ILC and serve as targets to overcome antiestrogen resistance in ILC. IMPLICATIONS: MDC1 has novel ER coregulator activity in ILC, which may underlie ILC-specific ER functions, estrogen response, and antiestrogen resistance.

Clinicopathological analysis of invasive cribriform carcinoma of the breast, with review of the literature

Invasive cribriform carcinoma (ICC) is a rare type of a primary breast carcinoma. It is subdivided into two groups as pure and mixed types. There are limited studies comparing the pure and mixed ICC at present. We aim to investigate the clinicopathological, radiological, prognostic features, and survival outcomes of two types with reviewing the published literature. 16 pure ICC and 26 mixed ICC cases were evaluated. The population consisted of 41 female and 1 male patients. The only male patient was a pure ICC case. The median age was for pure and mixed type, 46.5 and 54 years, respectively. All ICCs were ER positive. All ICCs except one mixed ICC, were positive for PR. Only one mixed ICC was accepted HER2 positive (3+). Pure ICCs showed more favorable features than mixed ICCs such as lesser axillary lymph node involvement, lower grade, and proliferation index. Twenty-five patients had one of the following imaging methods; ultrasonography (US), mammography (MG), and magnetic resonance imaging (MRI). Irregular shape, hypoechogenicity, and spiculated margins were the most common US findings. Similarly, irregular shape+spiculated margin is the most common MG findings. The median follow-up time for pure and mixed ICC was 88 and 56.5 months, respectively. One mixed ICC case developed bone metastasis. One death occurred in each group. Reasons of death were unknown. The 5-year OS for both ICC groups was 100%. 10-year OS for pure and mixed ICCs was 100% and 90%, respectively. 5-year DFS was 100% for pure ICC, and 94% for mixed ICC.

Lobular Breast Cancer: Histomorphology and Different Concepts of a Special Spectrum of Tumors

Simple Summary

Invasive lobular breast cancer (ILC) is a special type of breast cancer (BC) that was first described in 1941. The diagnosis of ILC is made by microscopy of tumor specimens, which reveals a distinct morphology. This review recapitulates the developments in the microscopic assessment of ILC from 1941 until today. We discuss different concepts of ILC, provide an overview on ILC variants, and highlight advances which have contributed to a better understanding of ILC as a special histologic spectrum of tumors.

Abstract

Invasive lobular breast cancer (ILC) is the most common special histological type of breast cancer (BC). This review recapitulates developments in the histomorphologic assessment of ILC from its beginnings with the seminal work of Foote and Stewart, which was published in 1941, until today. We discuss different concepts of ILC and their implications. These concepts include (i) BC arising from mammary lobules, (ii) BC growing in dissociated cells and single files, and (iii) BC defined as a morpho-molecular spectrum of tumors with distinct histological and molecular characteristics related to impaired cell adhesion. This review also provides a comprehensive overview of ILC variants, their histomorphology, and differential diagnosis. Furthermore, this review highlights recent advances which have contributed to a better understanding of the histomorphology of ILC, such as the role of the basal lamina component laminin, the molecular specificities of triple-negative ILC, and E-cadherin to P-cadherin expression switching as the molecular determinant of tubular elements in CDH1-deficient ILC. Last but not least, we provide a detailed account of the tumor microenvironment in ILC, including tumor infiltrating lymphocyte (TIL) levels, which are comparatively low in ILC compared to other BCs, but correlate with clinical outcome. The distinct histomorphology of ILC clearly reflects a special tumor biology. In the clinic, special treatment strategies have been established for triple-negative, HER2-positive, and ER-positive BC. Treatment specialization for patients diagnosed with ILC is just in its beginnings. Accordingly, ILC deserves greater attention as a special tumor entity in BC diagnostics, patient care, and cancer research.

Biological and clinical features of triple negative Invasive Lobular Carcinomas of the breast. Clinical outcome and actionable molecular alterations

Background

We report here for the first time, a comprehensive characterization of biological and clinical features of early-stage triple negative Invasive Lobular Carcinomas(TN-ILCs)

Methods

We analyzed all consecutive patients with early-stage TN-ILC operated at two reference cancer-centers between 1994 and 2012.

Primary objective was to assess the invasive disease-free survival(iDFS).

Co-primary objective was to assess biological features of TN-ILCs, including molecular intrinsic subtypes based on PAM-50 assay, expression of androgen receptor (AR) and mutational status of ERBB2-gene.

Additionally, DNA mutational status of an independent cohort of 45 TN-ILCs from three databases were analyzed, to confirm mutations in ERBB2-gene and to identify other recurrently mutated genes.

Results

Among 4152 ILCs, 74(1.8%) were TN and were analyzed.

The iDFS at 5 and 10 years of FUP were 50.4%(95%CI,38.0–61.6) and 37.2%(95%CI,25.5–48.8), respectively.

The molecular subtype was defined through PAM50-classifier for 31 out of 74 TN-ILCs: 48% were Luminal-A(15/31), 3% luminal-B(1/31), 32% HER2-enriched (10/31), and only 16% basal-like(5/31).

Luminal tumors expressed AR more frequently than non-luminal tumors (AR≥1% in 94% of luminal tumors versus 53% in non-luminal tumors; p-value = 0.001).

20% of TN-ILCs analyzed(7/35), harbored a pathogenetic and actionable mutation in the ERBB2-gene. Analysis of the independent cohort of 45 TN-ILCs from three different databases, confirmed similar percentage of pathogenetic and actionable mutations in ERBB2-gene(20%; 9/45).

Among the top 10 molecular pathways significantly enriched for recurrently mutated genes in TN-ILCs(FDR<0.05), there were ErbB-signaling and DNA-damage-response pathways.

Conclusions

TN-ILCs are rare tumors with poor prognosis. Their specific biological features require newly defined targeted therapeutic strategies

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Triple-negative ILCs are distinct from both TN-IDCs and endocrine-responsive ILC.

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TN-ILCs are enriched for actionable mutations in ErbB2 gene and DNA Damage Response genes.

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The Luminal Androgen Receptor (LAR) is the most prevalent subtype in TN-ILCs.

Association of antidiabetic medication and statins with survival from ductal and lobular breast carcinoma in women with type 2 diabetes

We investigated the survival of female patients with pre-existing type 2 diabetes (T2D) diagnosed with invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) of breast, in relation to the use of metformin, other antidiabetic medication (ADM) and statins. The study cohort consisted of 3,165 women (2,604 with IDC and 561 with ILC). The cumulative mortality from breast cancer (BC) and from other causes was calculated using the Aalen-Johansen estimator. The cause-specific mortality rates were analysed by Cox models, and adjusted hazard ratios (HRs) were estimated for the use of different medications. No evidence of an association of metformin use with BC mortality was observed in either IDC (HR 0.92, 95% confidence interval [CI] 0.64–1.31) or ILC (HR 0.68, 95% CI 0.32–1.46) patients, when compared to other oral ADMs. The mortality from other causes was found to be lower amongst the IDC patients using metformin (HR 0.64, 95% CI 0.45–0.89), but amongst ILC patients the evidence was inconclusive (HR 1.22, 95% CI 0.64–2.32). Statin use was consistently associated with reduced mortality from BC in IDC patients (HR 0.77, 95% CI 0.62–0.96) and ILC patients (HR 0.59, 95% CI 0.37–0.96), and also mortality from other causes in IDC patients (HR 0.81, 95% CI 0.67–0.96) and in ILC patients (HR 0.66, 95% CI 0.43–1.01). We found no sufficient evidence for the possible effects of metformin and statins on the prognosis of BC being different in the two histological subtypes.

Clinical Relevance of Tubular Breast Carcinoma: Large Retrospective Study and Meta-Analysis

Background: Tubular carcinoma (TC) is a low proliferative grade 1 (G1) breast cancer (BC). Despite its favorable outcome and allegedly lower aggressiveness, patients are treated like other luminal G1 BC, with radiotherapy (RT) and hormonal therapy (HT). We performed: (1) a retrospective study comparing a TC cohort and a control series of luminal G1 BC and (2) a systematic review and meta-analysis focused on TC outcome.

Materials and Methods: We selected a series of 572 G1 luminal BC patients [111 TC, 350 not otherwise specified (NOS), and 111 special-type (ST) BC] with follow-up and clinico-pathological data, who underwent local excision followed by RT at Città della Salute e della Scienza Hospital, Turin. Moreover, 22 and 13 studies were included in qualitative and quantitative meta-analysis, respectively.

Results: TCs were generally smaller (≤10 mm) (P < 0.001), with lower lymph node involvement (P < 0.001). TCs showed no local and/or distant recurrences, while 16 NOS and 2 ST relapsed (P = 0.036). Kaplan–Meier curves confirmed more favorable TC outcome (DFI: log-rank test P = 0.03). Meta-analysis data, including the results of our study, showed that the pooled DFI rate was 96.4 and 91.8% at 5 and 10 years, respectively. Meta-regression analyses did not show a significant influence of RT nor HT on the DFI at 10 years.

Conclusions: Compared to the other G1 BCs, TCs have an excellent outcome. The meta-analysis shows that TC recurrences are infrequent, and HT and RT have limited influence on prognosis. Hence, accurate diagnosis of TC subtype is critical to ensuring a tailored treatment approach.

Rare Breast Cancer Subtypes

PURPOSE OF REVIEW

Breast cancer is a collection of diseases including the more common invasive ductal and lobular carcinomas and rarer subtypes of breast cancer. This review summarizes the features of rare breast cancers.

RECENT FINDINGS

Each of the rare tumors has defined pathological and clinical features that impact treatment recommendations. In this review, we summarize these for each rare type of breast cancer and where available we include molecular features of each tumor. Rare subtypes of breast cancer each have unique features. In many cases, data is limited for the optimal treatment approaches.

Comparison of Overall Survival Between Invasive Lobular Breast Carcinoma and Invasive Ductal Breast Carcinoma: A Propensity Score Matching Study Based on SEER Database

Objective

Invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) account for most breast cancers. However, the overall survival (OS) differences between ILC and IDC remain controversial. This study aimed to compare nonmetastatic ILC to IDC in terms of survival and prognostic factors for ILC.

Methods

This retrospective cohort study used data from the Surveillance, Epidemiology and End Results (SEER) Cancer Database (www.seer.cancer.gov). Women diagnosed with nonmetastatic ILC and IDC between 2006 and 2016 were included. A propensity score matching (PSM) method was used in our analysis to reduce baseline differences in clinicopathological characteristics and survival outcomes. Kaplan-Meier curves and log-rank test were used for survival analysis.

Results

Compared to IDC patients, ILC patients were diagnosed later in life with poorly differentiated and larger lesions, as well as increased expression of estrogen receptors (ERs) and/or progesterone receptors (PRs). A lower rate of radiation therapy and chemotherapy was observed in ILC. After PSM, ILC, and IDC patients exhibited similar OS (HR=1.017, p=0.409, 95% CI: 0.967–1.069). In subgroup analysis of HR-negative, AJCC stage III, N2/N3 stage patients, or those who received radiotherapy, ILC patients exhibited worse OS compared to IDC patients. Furthermore, multivariate analysis revealed a 47% survival benefit for IDC compared to ILC in HR-negative patients who received chemotherapy (HR=1.47, p=0.01, 95% CI: 1.09–1.97).

Conclusions

Our results demonstrated that ILC and IDC patients had similar OS after PSM. However, ILC patients with high risk indicators had worse OS compared to IDC patients by subgroup analysis.

Breast Cancer in the United States: A Cross-Sectional Overview

Introduction

Breast cancer remains the most commonly diagnosed malignancy in women. It encompasses considerable heterogeneity in pathology, patient clinical characteristics, and outcome. This study describes factors associated with overall survival (OS) of breast cancer in an updated national database.

Methods

We conducted a retrospective analysis of patients with breast cancer diagnosed between 2004 and 2016 based on the National Cancer Database. Categorical variables were summarized using frequencies/percentages, whereas continuous variables were summarized using the median/interquartile range (IQR). OS was explored using the Kaplan-Meier method.

Results

Data from n = 2,671,549 patients were analyzed. The median age at diagnosis was 61 years (range 18-90). 75% were non-Hispanic (NH) White; 11% were NH-Black; 4.7% were Hispanic-White; 0.1% were Hispanic-Black; and 3.4% were Asian. Most cases (73%) presented with ductal carcinoma histology; while 15% with lobular carcinoma. Rarer subtypes included epithelial-myoepithelial, fibroepithelial, metaplastic, and mesenchymal tumors. OS was associated with molecular subtype, histologic subtype, and AJCC clinical staging. Survival also correlated with race: a cohort including Asians and Pacific Islanders had the best survival, while Black patients had the worst. Finally, facility type also impacted outcome: patients at academic centers had the best survival, while those at community cancer programs had the worst.

Conclusion

This large database provides a recent and comprehensive overview of breast cancer over 12 years. Molecular subtype, histologic subtype, stage, race, and facility type were correlated with OS. In addition to the educational perspective of this overview, significant factors impacting the outcome identified here should be considered in future cancer research on disparities.

Estrogen Regulation of mTOR Signaling and Mitochondrial Function in Invasive Lobular Carcinoma Cell Lines Requires WNT4

Simple Summary

Invasive lobular carcinoma (ILC) is a common but understudied breast cancer subtype. ILC is presumed to be a low-risk disease in part because nearly all ILCs contain the estrogen receptor (ER). However, we previously showed that ER has unique functions in ILC cells, including driving expression of the Wnt ligand WNT4. WNT4 signaling is required for ILC cell proliferation and survival, but the mechanisms and targets of WNT4 signaling in ILC is unknown. We found that WNT4 regulates mTOR signaling via S6 kinase, and controls levels of MCL-1 protein, ultimately regulating mitochondrial function and cellular metabolism. These findings offer new insight into a novel Wnt signaling pathway and identify new targets to inhibit WNT4 signaling as potential treatments against ILC cells.

Abstract

Invasive lobular carcinoma of the breast (ILC) is strongly estrogen-driven and represents a unique context for estrogen receptor (ER) signaling. In ILC, ER controls the expression of the Wnt ligand WNT4, which is critical for endocrine response and anti-estrogen resistance. However, signaling mediated by WNT4 is cell type- and tissue-specific, and has not been explored in ILC. We utilized reverse phase protein array (RPPA) to characterize ER and WNT4-driven signaling in ILC cells and identified that WNT4 mediates downstream mTOR signaling via phosphorylation of S6 Kinase. Additionally, ER and WNT4 control levels of MCL-1, which is associated with regulation of mitochondrial function. In this context, WNT4 knockdown led to decreased ATP production and increased mitochondrial fragmentation. WNT4 regulation of both mTOR signaling and MCL-1 were also observed in anti-estrogen resistant models of ILC. We identified that high WNT4 expression is associated with similar mTOR pathway activation in ILC and serous ovarian cancer tumors, suggesting that WNT4 signaling is active in multiple tumor types. The identified downstream pathways offer insight into WNT4 signaling and represent potential targets to overcome anti-estrogen resistance for patients with ILC.

Special subtypes with favorable prognosis in breast cancer: A registry-based cohort study and network meta-analysis

BACKGROUND

We aimed to explore whether cribriform and adenoid cystic carcinoma had comparable prognoses to mucinous, tubular and papillary carcinoma, which were long recognized as favorable histologies by NCCN guidelines.

METHODS

A retrospective analysis based on the Surveillance, Epidemiology, and End Results Study (SEER) database (1994-2014) was conducted. The prognostic significance of all clinicopathological factors was calculated using univariate and multivariate analyses. A systematic review based on PubMed and network meta-analysis was conducted.

RESULTS

From the SEER database, the histologic subtypes of breast cancer (tubular, cribriform, adenoid cystic, mucinous, and papillary) were sorted by overall survival (OS) (94.4%, 91.6%, 90.8%, 87.6%, and 84.2%, respectively) and tubular, cribriform, mucinous, papillary, and adenoid cystic carcinoma by breast cancer-specific survival (BCSS) (99.4%, 98.4%, 97.7%, 95.2%, and 94.9%, respectively). A network meta-analysis combining 11 studies (886,649 patients) was conducted, which demonstrated consistent outcomes. SEER-based analyses revealed that, among the favorable subtypes, systemic chemotherapy did not improve OS or BCSS in hormone receptor-positive, node-negative patients, validating that these subtypes are generally associated with excellent outcomes, for which systemic chemotherapy may not be warranted.

CONCLUSIONS

Our data are consistent with guidelines suggesting that the mucinous, tubular, and papillary subtypes of breast cancer have favorable histologies. SEER data and meta-analysis supports this favorable category to include adenoid cystic and cribriform carcinoma, whose OS and BCSS outcomes are comparable to the former three. These findings add to the body of data, suggesting that patients with these histologic subtypes confer excellent prognosis, which may guide optimal therapeutic management strategies.

Germline variants of Brazilian women with breast cancer and detection of a novel pathogenic ATM deletion in early-onset breast cancer

BACKGROUND

It is estimated that 5-10% of breast cancer cases are hereditary. The identification of pathogenic germline variants allows individualized preventive health care, improvement of clinical management and genetic counseling. Studies in ethnically admixed Latin American populations have identified regions with increased frequency of deleterious variants in breast cancer predisposing genes. In this context, the Brazilian population exhibits great genetic heterogeneity, and is not well represented in international databases, which makes it difficult to interpret the clinical relevance of germline variants.

METHODS

We evaluated the frequency of pathogenic/likely pathogenic (P/LP) germline variants in up to 37 breast cancer predisposing genes, in a cohort of 105 breast and/or ovarian cancer Brazilian women referred to two research centers between 2014 and 2019.

RESULTS

A total of 22 patients (21%) were found to carry P/LP variants, and 16 VUS were detected in 15 patients (14.3%). Additionally, a novel pathogenic ATM intragenic deletion was identified in an early-onset breast cancer. We also detected a BRCA1 pathogenic variant (c.5074+2T>C) in higher frequency (10×) than in other studies with similar cohorts.

CONCLUSIONS

Our findings contribute to the characterization of the genetic background of breast cancer predisposition in the Brazilian population as a useful resource to discriminate between deleterious variants and VUS, thus enabling improvement in the preventive health care and clinical management of carriers.

Characteristics and prognosis of 17 special histologic subtypes of invasive breast cancers according to World Health Organization classification: comparative analysis to invasive carcinoma of no special type

BACKGROUND

Breast cancer is a heterogeneous disease with various histopathologic subtypes. Except for invasive carcinoma of no special type (NST), other subtypes are rare with limited data. The purpose of this study was to analyze the characteristics and prognosis of special histopathologic subtypes of breast cancer compared to NST.

METHODS

A total of 136,140 patients were analyzed using the Korean Breast Cancer Society Registry database between January 1996 and March 2019. The clinicopathologic features and survival outcomes of special type breast carcinoma were compared with those of NST.

RESULTS

The prevalence of special subtypes other than NST was 13.7% (n = 18,633). Compared to NST, patients with lobular, medullary, metaplastic, and micropapillary carcinoma had larger tumors (p < 0.001). Patients with mucinous, tubular, medullary, metaplastic, and cribriform carcinoma presented with less node metastasis (p < 0.001), contrary to patients with micropapillary carcinoma. Patients with lobular, mucinous, tubular, papillary, and cribriform carcinoma presented as luminal A subtype much more often (p < 0.001). Micropapillary carcinoma included more luminal B subtype (p < 0.001). Typically, medullary and metaplastic carcinoma included more triple-negative subtypes (p < 0.001). In survival analysis, only medullary (Hazard Ratio (HzR) 0.542, 95% CI 0.345 to 0.852, p = 0.008) and metaplastic carcinoma (HzR 1.655, 95% CI 1.317 to 2.080, p < 0.001) showed significantly different overall survival from NST by multivariate analysis.

CONCLUSION

Breast cancer had distinct clinicopathologic features according to histopathologic subtype. However, special types of breast cancer had similar survival outcomes compared to NST when adjusting for other prognostic factors, except for metaplastic carcinoma and medullary carcinoma.

Clinicopathological and genomic features of breast mucinous carcinoma

Introduction

Mucinous carcinoma (MC) of the breast is a special histological type of breast cancer. Clinicopathological characteristics and genomic features of MC is not fully understood.

Materials and methods

186,497 primary breast cancer patients from SEER database diagnosed with invasive ductal carcinoma (IDC) or MC were included. 801 primary IDC or MC patients from TCGA cohort were included for transcriptomic and genomic analysis.

Results

MC patients were older, had lower tumor grade and T and N stage, higher hormone receptor positive proportions and lower HER2 positive proportions than IDC patients. Kaplan-Meier plots showed that the breast cancer-specific survival (BCSS) of MC patients was significantly better than IDC patients (P < 0.001). However, after adjusting for clinicopathological factors, survival advantage of MC disappeared. In terms of genomic features of MC, representative upregulated genes of MC in transcriptomic level were MUC2, TFF1 and CARTPT. Upregulated pathways of MC included neurotransmitter-related pathways. Moreover, MC was featured by the amplification of 6p25.2, 6q12 and 11q12.3.

Conclusion

MC is a distinct histological subtype compared with IDC in terms of clinicopathological characteristics and genomic features. Further investigation need to be conducted to explore the formation of this specific histological subtype.

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Mucinous breast carcinoma is a distinct histological subtype with better prognosis.

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The clinicopathological characteristics of mucinous breast carcinoma contributed to its good prognosis.

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Transcriptomic and genomic features of mucinous breast carcinoma contributed to its formation.

Invasive Lobular Breast Cancer as a Distinct Disease: Implications for Therapeutic Strategy

Invasive lobular carcinoma comprises 10-15% of all breast cancers and is increasingly recognised as a distinct and understudied disease compared with the predominant histological subtype, invasive ductal carcinoma. Hallmarks of invasive lobular carcinoma include E-cadherin loss, leading to discohesive morphology with cells proliferating in single-file strands and oestrogen receptor positivity, with favourable response to endocrine therapy. This review summarises the distinct histological and molecular features of invasive lobular carcinoma with focus on diagnostic challenges and the impact on surgical management and medical therapy. Emphasis is placed on recent advances in our understanding of the unique molecular biology of lobular breast cancer and how this is optimising our therapy approach in the clinic.

Pitfalls and controversies in pathology impacting breast cancer management

Introduction: Breast cancer is a heterogeneous disease, at morphological, molecular, and clinical levels and this has significant implications for the diagnosis and management of the disease. The introduction of breast screening, and the use of small tissue sampling for diagnosis, the recognition of new morphological and molecular subtypes, and the increasing use of neoadjuvant therapies have created challenges in pathological diagnosis and classification.Areas covered: Areas of potential difficulty include columnar cell lesions, particularly flat epithelial atypia, atypical ductal hyperplasia, lobular neoplasia and its variants, and a range of papillary lesions. Fibroepithelial, sclerosing, mucinous, and apocrine lesions are also considered. Established and newer prognostic and predictive markers, such as immune infiltrates, PD-1 and PD-L1 and gene expression assays are evaluated. The unique challenges of pathology assessment post-neoadjuvant systemic therapy are also explored.Expert opinion: Controversies in clinical management arise due to incomplete and sometimes conflicting data on clinicopathological associations, prognosis, and outcome. The review will address some of these challenges.

Loss of function of NF1 is a mechanism of acquired resistance to endocrine therapy in lobular breast cancer

Background

Invasive lobular carcinoma (ILC) as a disease entity distinct from invasive ductal carcinoma (IDC) has merited focused studies of the genomic landscape, but those to date are largely limited to the assessment of early-stage cancers. Given that genomic alterations develop as acquired resistance to endocrine therapy, studies on refractory ILC are needed.

Patients and methods

Tissue from 336 primary-enriched, breast-biopsied ILC and 485 estrogen receptor (ER)-positive IDC and metastatic biopsy specimens from 180 ILC and 191 ER-positive IDC patients was assayed with hybrid-capture-based comprehensive genomic profiling for short variant, indel, copy number variants, and rearrangements in up to 395 cancer-related genes.

Results

Whereas ESR1 alterations are enriched in the metastases of both ILC and IDC compared with breast specimens, NF1 alterations are enriched only in ILC metastases (mILC). NF1 alterations are predominantly under loss of heterozygosity (11/14, 79%), are mutually exclusive with ESR1 mutations [odds ratio = 0.24, P < 0.027] and are frequently polyclonal in ctDNA assays. Assessment of paired specimens shows that NF1 alterations arise in the setting of acquired resistance. An in vitro model of CDH1 mutated ER-positive breast cancer demonstrates that NF1 knockdown confers a growth advantage in the presence of 4-hydroxy tamoxifen. Our study further identified a significant increase in tumor mutational burden (TMB) in mILCs relative to breast ILCs or metastatic IDCs (8.9% >20 mutations/mb; P < 0.001). Most TMB-high mILCs harbor an APOBEC trinucleotide signature (14/16; 88%).

Conclusions

This study identifies alteration of NF1 as enriched specifically in mILC. Mutual exclusivity with ESR1 alterations, polyclonality in relapsed ctDNA, and de novo acquisition suggest a role for NF1 loss in endocrine therapy resistance. Since NF1 loss leads to RAS/RAF kinase activation, patients may benefit from a matched inhibitor. Moreover, for an independent subset of mILC, TMB was elevated relative to breast ILC, suggesting possible benefit from immune checkpoint inhibitors.

Endocrine-responsive lobular carcinoma of the breast: features associated with risk of late distant recurrence

Background

Invasive lobular carcinomas (ILCs) account for 10–15% of all breast cancers. They are characterized by an elevated endocrine responsiveness and by a long lasting risk of relapse over time. Here we report for the first time an analysis of clinical and pathological features associated with the risk of late distant recurrence in ILCs.

Patients and methods

We retrospectively analyzed all consecutive patients with hormone receptor–positive ILC operated at the European Institute of Oncology (EIO) between June 1994 and December 2010 and scheduled to receive at least 5 years of endocrine treatment.

The aim was to identify clinical and pathological variables that provide prognostic information in the period beginning 5 years after definitive surgery. The cumulative incidence of distant metastases (CI-DM) from 5 years after surgery was the prospectively defined primary endpoint.

Results

One thousand eight hundred seventy-two patients fulfilled the inclusion criteria. The median follow-up was 8.7 years.

Increased tumor size and positive nodal status were significantly associated with higher risk of late distant recurrence, but nodal status had a significant lower prognostic value in late follow-up period (DM-HR, 3.21; 95% CI, 2.06–5.01) as compared with the first 5 years of follow-up (DM-HR, 9.55; 95% CI, 5.64–16.2; heterogeneity p value 0.002).

Elevated Ki-67 labeling index (LI) retained a significant and independent prognostic value even after the first 5 years from surgery (DM-HR, 1.81; 95% CI 1.19–2.75), and it also stratified the prognosis of ILC patients subgrouped according to lymph node status.

A combined score, obtained integrating the previously validated Clinical Treatment Score post 5 years (CTS5) and Ki-67 LI, had a strong association with the risk of late distant recurrence of ILCs.

Conclusion

We identified factors associated with the risk of late distant recurrence in ER-positive ILCs and developed a simple prognostic score, based on data that are readily available, which warrants further validation.

E-cadherin clone 36 nuclear staining dictates adverse disease outcome in lobular breast cancer patients

Breast cancer is a heterogeneous disease and additional biomarkers for individually predicting patient outcomes are needed. Aberrant membrane E-cadherin immunoexpression has been demonstrated in lobular breast cancer. Also, E-cadherin nuclear staining has been reported, associating with prognosis in various tumors. Here, we explore whether membrane or nuclear staining of E-cadherin has the potential to dictate prognosis of patients with lobular breast cancer. We selected a cohort of 285 consecutively diagnosed lobular breast cancer patients and performed immunohistochemistry for E-cadherin (clones 36, EP700Y, and NCH38) and P-cadherin (clone 56C1) in representative formalin-fixed paraffin-embedded blocks. All patients were female, HER2-negative and surgically treated in a single institution. Survival curves were computed by Kaplan-Meier analysis. Hazard ratios and respective 95% confidence intervals were estimated using Cox regression models. Statistical significance was set at p < 0.05. Nuclear staining for E-cadherin clone 36 was frequent (35%), contrarily to other antibodies tested. Negative correlation was found between nuclear and membrane E-cadherin clone 36 immunostaining (r_s = -0.30, p < 0.001), whereas positive correlation was found between membrane immunoexpression of E-cadherin clone 36 and P-cadherin (r_s = 0.31, p < 0.001). Patients with any evidence of E-cadherin clone 36 nuclear immunostaining disclosed significantly worse overall survival, disease-specific-survival and disease/progression-free survival (hazard ratio = 2.059, 95% confidence interval 1.313-3.230; hazard ratio = 1.980, 95% confidence interval 1.121-3.495; and hazard ratio = 2.341, 95% confidence interval 1.403-3.905, respectively). Differences in survival were more remarkable when considering nuclear E-cadherin immunoexpression in ≥50% tumor cells. Poorer survival was maintained in multivariable analysis, after adjusting for age, menopausal and PR status, treatment course, vascular invasion, tumor grade and stage. Our results support the use of antibodies against the cytoplasmic domain of E-cadherin, such as clone 36, which may reveal nuclear immunostaining and indicate more aggressive clinical course in patients with lobular breast cancer. We hypothesize that E-cadherin is cleaved and translocated to nucleus functioning as transcription factor.

Clinical significance of the cribriform pattern in invasive adenocarcinoma of the lung

PURPOSE

According to the WHO, the cribriform pattern is a subtype of acinar (Aci) predominance in invasive adenocarcinoma (ADC) of the lung. Recently, several studies have demonstrated poor prognosis in patients with cribriform predominance. This study was performed to examine the correlations of cribriform pattern with the clinicopathology, molecular features and prognosis in patients with invasive ADC.

METHODS

Histological subtypes were evaluated in 279 patients who underwent complete resection for invasive ADC. Patients of the Aci-predominant subtype were divided into two subgroups according to the percentage of cribriform cancer (≥5% vs <5%). Clinicopathological characteristics, overall survival (OS), disease-free survival (DFS) and molecular changes were compared. In addition, both OS and DFS were compared between patients with cribriform-predominant (n=33) and pure Aci-predominant (n=88) ADCs.

RESULTS

A cribriform pattern was found in 111 (39.8%) cases and ranged from 5 % to 100 % of the total tumour volume (mean±SEM, 30%±2%). Of 117 patients with Aci predominance, 79 showed the cribriform pattern, while the remaining 38 did not. The cribriform pattern was associated with aggressive pathological behaviour, including advanced stages of cancer, nuclear atypia, mitoses, lymph node invasion, metastasis and larger tumour size. The subgroup with cribriform cancer (≥5%) had significantly poorer OS and DFS compared with the cribriform-negative (<5%) group. In addition, Cox multivariate analyses revealed that the cribriform pattern was an independent predictor of OS but not DFS. Moreover, OS was significantly lower in the cribriform-predominant group than in the Aci-predominant group.

CONCLUSION

The cribriform pattern is associated with aggressive pathological behaviour and is an independent poor prognostic indicator in patients with Aci-predominant ADC of the lung.

Impact of invasive lobular carcinoma on long-term outcomes in Mexican breast cancer patients

PURPOSE

The aim of this study was to compare the difference in disease-free survival (DFS) and overall survival (OS) between invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) in our Hispanic population with breast cancer (BC).

METHODS

We retrospectively analyzed a database of 4533 non-metastatic BC patients treated for BC at the National Cancer Institute in Mexico (INCan) between 2006 and 2016. We compared clinical characteristics, treatment and survival between women with invasive ductal and invasive lobular BC. We evaluated differences between survival curves with the log-rank test and used Cox's proportional hazards model for the multivariate analysis.

RESULTS

Median follow-up time was 42.13 months (IQ₂₅ 25.2-IQ₇₅ 72.06). The median age was 50.9 years (IQ₂₅ 43.5-IQ₇₅ 59.8). DFS at 5 years was 80.8% for IDC versus 76.2% for ILC. 5 years OS was 88.7% for IDC versus 84.3% for ILC. Multivariate analysis showed that factors that negatively affected the 5-year DFS include: clinical stage III [hazard ratio (HR) 4.2, 95% CI 3.36-5.35; p < 0.001], triple negative phenotype (HR 1.4, 95% CI 1.08-1.81; p = 0.009), Ki67 ≥ 18 (HR 1.6, 95% CI 1.28-2.11; p < 0.001), and lobular histological type (HR 1.6, 95% CI 1.09-2.49; p = 0.017). Factors associated with a negative impact on OS were: clinical stage III (HR 4.5, 95% CI 3.15-6.54; p < 0.001), triple negative phenotype (HR 2.4, 95% CI 1.69-3.48; p < 0.001), and Ki67 ≥ 18% (HR 1.9, 95% CI 1.27-2.92; p = 0.02).

CONCLUSION

Our results highlight the different biology of ILC and show that long-term prognosis in terms of DFS is not as favorable as previously reported.

Breast Carcinoma: Updates in Molecular Profiling 2018

The most significant contribution of molecular subtyping of breast carcinomas has been the identification of estrogen-positive and estrogen-negative tumor subtypes. Knowledge of genetic alterations in these tumors will help clinicians identify novel therapeutic targets. Understanding the progression pathways involved in the transition of in situ carcinoma to invasive carcinoma might lead to efficient risk stratification in these patients. The Cancer Genome Analysis Network has collected genomic and epigenomic data to provide comprehensive information regarding carcinogenesis and pathway interactions. Such information improves understanding of the disease process and also provides more accurate information toward identifying targetable mutations for treatment.

ERBB2 mutation frequency in lobular breast cancer with pleomorphic histology or high-risk characteristics by molecular expression profiling

HER2-positive breast cancer is defined by amplification or overexpression of the HER2/ERBB2 oncogene and accounts for about 15% of breast cancer cases. Somatic mutation of ERBB2 is an alternative mechanism, by which activation of HER2 signaling can occur. ERBB2 mutation has been associated with invasive lobular breast cancer (ILBC). This study investigates the frequency and phenotype of ILBC harboring mutated ERBB2. The ERBB2 mutation status was determined by next generation sequencing and/or pyrosequencing in n = 106 ILBCs, including n = 86 primary or locally recurrent tumors and n = 20 metastases from visceral organs, soft tissue, or skin. Immunohistochemical characteristics were determined using tissue microarrays. This series was enriched for ILBCs with pleomorphic histology and/or high-risk expression profiles (Oncotype DX, recurrence score RS > 25). Nearly all specimens were E-cadherin-negative (99%), estrogen receptor (ER)-positive (92%), and lacked ERBB2 overexpression (96%). ERBB2 mutations (p.V777L, p.L755S, p.S310F) were identified in 5/106 (5%) cases. ERBB2-mutated cases included 2/86 (2%) primary tumors and 3/20 (15%) metastases (P = 0.045). ERBB2-mutated cases were associated with loss of ER (2/7, 29%, P = 0.035) and histological grade 3 (4/34, 12%, P = 0.023), but not with solid growth (3/31, 10%, P = 0.148) or pleomorphic histology (2/27, 7%, P = 0.599). No ERBB2 mutation was detected in ILBCs with RS > 25 (0/22, 0%). In 10 patients with multiple matched specimens (n = 25), the ERBB2 mutational status was always concordant. In summary, a small subset of ILBCs harbors potentially actionable ERBB2 mutations. In ERBB2-mutated ILBCs, no association with pleomorphic histology was found.

Cribriform pattern in lung invasive adenocarcinoma correlates with poor prognosis in a Chinese cohort

The 2011 International　Association　for　the　Study　of　Lung　Cancer/American　Thoracic　Society/European　Respiratory　Society (IASLC/ATS/ERS) lung adenocarcinoma classification and the following 2015 WHO classification have both been validated for their predictive values of histologic subtypes for prognosis. We sought to investigate the clinicopathological and prognostic significance of the cribriform pattern in lung adenocarcinomas. Histologic subtypes were evaluated in 395 patients who underwent complete resection for invasive lung adenocarcinomas between 2011 and 2013. Cribriform pattern was correlated with clinicopathological factors as well as molecular and survival data. One hundred and thirty cases (33%) were present with cribriform pattern (5-100%; mean ± SD, 24% ± 22%). Thirty two (8%) of those were reclassified into cribriform predominant tumors. Presence of cribriform pattern (≥5%) was significantly associated with lymph/vascular invasion (P＜0.001), nodal positivity (P = 0.003), higher T stage(P = 0.005) and higher TNM stage (P = 0.001). Cribriform pattern (≥10%) was highly associated with worse disease-free survival (DFS) and overall survival (OS) (mean DFS: 42.6 months, P < 0.001; mean OS: 64.1 months, P = 0.012). The DFS or OS for cribriform predominant tumors was similar to that for solid or micropapillary tumors. In multivariate analysis, cribriform pattern (≥10%) or cribriform predominant subtype was an independent predictor for DFS. Cribriform pattern was a specific pattern compared to other acinar patterns, presenting with more aggressive behavior. Moreover, presence of cribriform pattern was a strong predictor for worse prognosis and should be considered a high grade pattern. Our study provides further evidence for cribriform pattern to be acknowledged as an independent subtype in the future classification.

Mixed Invasive Ductal and Lobular Carcinoma of the Breast: Prognosis and the Importance of Histologic Grade

BACKGROUND

The diagnosis of mixed invasive ductal and lobular carcinoma (IDC-L) in clinical practice is often associated with uncertainty related to its prognosis and response to systemic therapies. With the increasing recognition of invasive lobular carcinoma (ILC) as a distinct disease subtype, questions surrounding IDC-L become even more relevant. In this study, we took advantage of a detailed clinical database to compare IDC-L and ILC regarding clinicopathologic and treatment characteristics, prognostic power of histologic grade, and survival outcomes.

MATERIALS AND METHODS

In this retrospective cohort study, we identified 811 patients diagnosed with early-stage breast cancer with IDC-L or ILC. Descriptive statistics were performed to compare baseline clinicopathologic characteristics and treatments. Survival rates were subsequently analyzed using the Kaplan-Meier method and compared using the Cox proportional hazards model.

RESULTS

Patients with ILC had more commonly multifocal disease, low to intermediate histologic grade, and HER2-negative disease. Histologic grade was prognostic for patients with IDC-L but had no significant discriminatory power in patients with ILC. Among postmenopausal women, those with IDC-L had significantly better outcomes when compared with those with ILC: disease-free survival (DFS) and overall survival (OS; adjusted hazard ratio [HR], 0.54; 95% confidence interval [CI] 0.31-0.95). Finally, postmenopausal women treated with an aromatase inhibitor had more favorable DFS and OS than those treated with tamoxifen only (OS adjusted HR, 0.50; 95% CI, 0.29-0.87), which was similar for both histologic types (p = .212).

CONCLUSION

IDC-L tumors have a better prognosis than ILC tumors, particularly among postmenopausal women. Histologic grade is an important prognostic factor in IDC-L but not in ILC.

IMPLICATIONS FOR PRACTICE

This study compared mixed invasive ductal and lobular carcinoma (IDC-L) with invasive lobular carcinomas (ILCs) to assess the overall prognosis, the prognostic role of histologic grade, and response to systemic therapy. It was found that patients with IDC-L tumors have a better prognosis than ILC, particularly among postmenopausal women, which may impact follow-up strategies. Moreover, although histologic grade failed to stratify the risk of ILC, it showed an important prognostic power in IDC-L, thus highlighting its clinical utility to guide treatment decisions of IDC-L. Finally, the disease-free survival advantage of adjuvant aromatase inhibitors over tamoxifen in ILC was consistent in IDC-L.

The effects of postoperative radiotherapy on survival outcomes in patients under 65 with estrogen receptor positive tubular breast carcinoma

Background

The value of postoperative radiotherapy in tubular breast carcinoma patients under 65 years is uncertain.

Methods

Data on patients with estrogen receptor positive T1N0M0 tubular breast carcinoma who were younger than 65 years and who received breast-conserving surgery between 2000 and 2013 were retrieved from the Surveillance, Epidemiology and End Results database. Demographic, clinicopathologic features, and receipt of postoperative radiotherapy were analyzed to investigate effects on survival.

Results

Data from 2442 patients were analyzed, of whom 2020 (82.7%) received postoperative radiotherapy and 422 (17.3%) did not. The number of patients treated with or without postoperative radiotherapy showed no differences during the study period (p = 0.184). Radiotherapy was more likely to be administered in patients with well differentiated tumors. Multivariate Cox analysis showed that postoperative radiotherapy delivery was significantly correlated with better breast cancer-specific survival (BCSS) (hazard ratio [HR] 0.297, 95% confidence interval [CI] 0.105–0.836, p = 0.022) and overall survival (OS) (HR 0.656, 95% CI 0.441–0.978, p = 0.038). Ten 10-year BCSS was 99.3% in patients who received postoperative radiotherapy and 98.1% in those who did not (p = 0.020), and 10-year OS was 93.4 and 91.0%, respectively (p = 0.029). Postoperative radiotherapy increased BCSS and OS in the subgroups of age < 50 years, non-Hispanic white, well differentiated tumors, and progesterone receptor positive tumors.

Conclusions

Postoperative radiotherapy after breast-conserving surgery improved survival outcomes in tubular breast carcinoma patients aged < 50 years. However, omitting postoperative radiotherapy may not decrease survival in patients aged ≥50 years.

PROGNOSTIC IMPACT OF LOW ESTROGEN AND PROGESTERONE POSITIVITY IN LUMINAL B (HER2 NEGATIVE) BREAST CANCER

- Luminal B (HER2 negative) subtype is the most diversiform type of breast cancers, with a high Ki-67 proliferation index (>20%) or/and low progesterone (PR; <20%) with various intensity and distribution of hormone receptors. Considerable difference has also been noticed in disease outcome, wherefore there is the need for a more detailed classification of this tumor subtype. The clinical and pathologic parameters of 147 luminal B (HER2 negative) breast cancers were examined. The expression of hormone receptors in correlation with other prognostic factors and disease outcome was analyzed by Kaplan-Meier curves and multivariate Cox regression analysis. The Kaplan-Mayer analysis showed that low positivity of estrogen (ER) and PR receptors in tumors was associated with a significantly worse disease outcome (overall survival (ER), p=0.020; disease free survival (ER), p=0.019; overall survival (PR), p=0.026; disease free survival (PR), p=0.038)), unlike Ki-67, which did not show a statistically significant connection (overall survival, p=0.343; disease free survival, p=0.322). The intensity of receptor staining and Ki-67 relative to other histopathologic prognostic factors showed a statistically significant correlation solely with histologic grade of tumor. By using the Cox regression model, PR proved to be an independent prognostic factor for overall survival (p=0.004) and disease free survival (p=0.029). The luminal B (HER2 negative) breast cancer with low expression of hormone receptors, independent of the Ki-67 proliferation index, and in correlation with a higher histologic grade, could be a unique subtype of cancer.

Integrated molecular analysis of Tamoxifen-resistant invasive lobular breast cancer cells identifies MAPK and GRM/mGluR signaling as therapeutic vulnerabilities

Invasive lobular breast cancer (ILC) is an understudied malignancy with distinct clinical, pathological, and molecular features that distinguish it from the more common invasive ductal carcinoma (IDC). Mounting evidence suggests that estrogen receptor-alpha positive (ER+) ILC has a poor response to Tamoxifen (TAM), but the mechanistic drivers of this are undefined. In the current work, we comprehensively characterize the SUM44/LCCTam ILC cell model system through integrated analysis of gene expression, copy number, and mutation, with the goal of identifying actionable alterations relevant to clinical ILC that can be co-targeted along with ER to improve treatment outcomes. We show that TAM has several distinct effects on the transcriptome of LCCTam cells, that this resistant cell model has acquired copy number alterations and mutations that impinge on MAPK and metabotropic glutamate receptor (GRM/mGluR) signaling networks, and that pharmacological inhibition of either improves or restores the growth-inhibitory actions of endocrine therapy.

Breast Cancers of Special Histologic Subtypes Are Biologically Diverse

BACKGROUND/OBJECTIVE

Cancers classified as "special histologic subtypes" are felt to have a good prognosis. We used the 21-gene Oncotype DX Breast Recurrence Score^® multigene assay to examine prognostic variation within special histologic subtypes. We also examined the Recurrence Score^® (RS) distribution among the more common ductal (IDC) and lobular (ILC) cancers.

METHODS

610,350 tumor specimens examined in the Genomic Health clinical laboratory from 2/2004 to 8/2017 were included. Specimen histology was classified centrally using a single H&E slide and World Health Organization criteria. RS distribution (low < 18, intermediate 18-30, and high ≥ 31) was compared among histologic subtypes.

RESULTS

Median patient age was 60 years (IQR 51-67); 80% were node negative. Most patients had low RS results (59.2%); only 9.5% had high results. The lowest mean RS was seen in the papillary subtype (11); the highest in the IDC group (18.4). Mean RS for all special subtypes was lower than that of IDC patients. When the high RS threshold was decreased from 31 to 25, as used in the TAILORx and RxPONDER trials, the number of high RS-result patients increased from 9.5% to 16.8%. Patients with ILC had a lower mean RS result than patients with IDC, 16.5 versus 18.4.

CONCLUSION

There is substantial diversity in predicted prognosis among patients with cancers classified as special histologic subtypes, with 12-25% having intermediate RS results and 0.5-9% having high RS results. Pending further definition of the role of chemotherapy for patients with intermediate RS results by TAILORx and RxPONDER, the RS result may help to inform systemic therapy decisions in these patients.

Tubular carcinomas of the breast: an epidemiologic study

AIM

We explored the clinicopathologic characteristics, prognostic factors and outcomes in tubular carcinoma (TC) of the breast.

METHODS

We retrospectively assessed 8091 TC patients using the SEER database from 2000 to 2013.

RESULTS

Most patients were non-Hispanic white, well-differentiated disease, tumor size ≤2 cm, node-negative, nonmetastatic, hormone receptor-positive and HER2-negative status. The 10-year breast cancer-specific survival and overall survival were 98.1 and 82.0%, respectively. Multivariate analysis indicated that age, ethnicity, surgery procedures, radiotherapy and chemotherapy were independent predictors affecting survival outcomes. There was comparable breast cancer-specific survival between surgery and nonsurgery groups.

CONCLUSION

The patients with TC has excellent survival outcomes, which may in part be due to the favorable tumor characteristics.

Omission of Postoperative Radiotherapy in Women Aged 65 Years or Older With Tubular Carcinoma of the Breast After Breast-Conserving Surgery

Introduction

To investigate the temporal trends of postoperative radiotherapy (RT) administration and the effects of omitting postoperative RT on breast cancer-specific survival (BCSS) in women aged ≥65 years with tubular carcinoma (TC) of the breast who received breast-conserving surgery (BCS).

Methods

We included women aged ≥65 years with non-metastatic TC of the breast who underwent BCS between 2000 and 2013 using the Surveillance, Epidemiology, and End Results database. Statistical analyses were performed using chi-square tests, Kaplan–Meier analyses, Cox proportional hazards models, and a 1:1 propensity score matching (PSM).

Results

Before PSM, a total of 1,475 patients with tumor size ≤2 cm, node-negative disease, and estrogen receptor-positive disease were identified, including 927 (62.8%) underwent postoperative RT and 548 (37.2%) had postoperative omission of RT. The administration of postoperative RT steadily declined over the study period. Patients with younger age, larger tumor size, and other race/ethnicity were more likely to receive postoperative RT. The median follow-up duration was 85.0 months, the 5- and 10-year BCSS rates were 98.7 and 97.9%, respectively. The median BCSS was 161.9 and 165.0 months for patients with and without postoperative RT, respectively, and the corresponding 5-year BCSS rates were 98.5 and 98.8%, respectively (p = 0.134). Prognostic analysis indicated that postoperative RT was not associated with improved BCSS rates compared with RT omission (p = 0.134). After PSM, a total of 431 complete pairs were generated. In the matched population, the 5-year BCSS rates were 98.6 and 98.4% in non-postoperative RT and postoperative RT groups, respectively (p = 0.858). The univariate analyses also confirmed that the administration of postoperative RT was not associated with better BCSS (p = 0.858).

Conclusion

The incidence of breast cancer-related death is probably sufficiently low to avoid postoperative RT in women aged ≥65 years with TC of the breast after BCS.

Clinicopathologic features and prognoses of different histologic types of triple-negative breast cancer: A large population-based analysis

PURPOSE

To examine the clinicopathologic characteristics and survival outcomes of different histologic types of triple-negative breast cancer (TNBC).

METHODS

We used the SEER database to identify patients with TNBC diagnosed between 2010 and 2014. Our analysis focused on the seven most prevalent histologic types. Differences were compared between invasive carcinoma of no special type (NST) and the other six types.

RESULTS

Significant differences were observed in age at diagnosis, tumor grade, size, nodal status and treatment. As tumor size increased, the number of positive lymph nodes increased markedly in invasive lobular carcinoma (ILC) and mixed NST and lobular carcinoma (NST-ILC), while in metaplastic carcinoma the number only increased slightly. In multivariate survival analyses, compared with patients with invasive carcinoma NST, breast cancer-specific survival (BCSS) and overall survival (OS) were worse for those with NST-ILC (BCSS: hazard ratio [HR] 1.81, P < .001; OS: HR 1.56, P = .005) or metaplastic carcinoma (BCSS: HR 1.95, P < .001; OS: HR 1.73, P < .001). By contrast, patients with medullary (HR 0.40, P = .010) or apocrine carcinoma (HR 0.27, P = .008) showed better BCSS. Time-dependent receiver operating characteristic (ROC) analyses indicated that T category in ILC and N category in metaplastic carcinoma were of less prognostic value.

CONCLUSIONS

According to the histologic classification of TNBC, this heterogeneous disease can be divided into several entities with different clinicopathologic features and prognoses. In the era of molecular subtyping of breast cancer, the histologic classification of TNBC is still of considerable clinical significance.

Differential expression and clinical significance of epithelial-mesenchymal transition markers among different histological types of triple-negative breast cancer

Background: Triple-negative breast cancer (TNBC) is a heterogeneous disease closely associated with epithelial-to-mesenchymal transition (EMT). This study aimed to investigate the role of EMT in metaplastic carcinoma.

Methods: E-cadherin, Slug, Twist and Vimentin levels were detected by immunohistochemistry in 167 TNBC tumors, including 145 invasive carcinomas of no special type (ICONSTs), 14 spindle cell carcinomas (SpCCs) and 8 matrix-producing carcinomas (MPCs).

Results: Nuclear Slug and Twist were more frequently detected in SpCC and MPC tumors than that in ICONST tumors (p<0.001). The rate of E-cadherin loss was much lower in the ICONST tumors than that in the SpCC and MPC tumors (p<0.001). Vimentin was expressed in all SpCC and MPC tumors. Furthermore, nuclear expression of Slug and Twist was positively associated with the cytoplasmic localization of Vimentin (p<0.001) and was inversely associated with membranous staining of E-cadherin (p<0.001). These trends were more apparent in the SpCC and MPC tumors than in the ICONST tumors. Follow-up data were available for 151 patients. The follow-up times ranged from 1 month to 11 years (mean: 74 m; median: 21 m). The median progression-free survival and overall survival times were 24 months (mean: 32 months) and 22 months (mean: 35 months), respectively. Tumor size, TNM stage and E-cadherin were found to be independent prognostic factors of TNBC.

Conclusions: EMT may play an important role in TNBC, especially in MPC and SpCC. Further researches are needed to confirm this finding. The results of this study may facilitate the future development of targeted therapies based on alterations in the EMT and stem cell markers.

Neoadjuvant tamoxifen synchronizes ERα binding and gene expression profiles related to outcome and proliferation

Estrogen receptor alpha (ERα)-positive breast cancers are frequently treated with tamoxifen, but resistance is common. It remains elusive how tamoxifen resistance occurs and predictive biomarkers for treatment outcome are needed. Because most biomarker discovery studies are performed using pre-treatment surgical resections, the effects of tamoxifen therapy directly on the tumor cell in vivo remain unexamined. In this study, we assessed DNA copy number, gene expression profiles and ERα/chromatin binding landscapes on breast tumor specimens, both before and after neoadjuvant tamoxifen treatment. We observed neoadjuvant tamoxifen treatment synchronized ERα/chromatin interactions and downstream gene expression, indicating that hormonal therapy reduces inter-tumor molecular variability. ERα-synchronized sites are associated with dynamic FOXA1 action at these sites, which is under control of growth factor signaling. Genes associated with tamoxifen-synchronized sites are capable of differentiating patients for tamoxifen benefit. Due to the direct effects of therapeutics on ERα behavior and transcriptional output, our study highlights the added value of biomarker discovery studies after neoadjuvant drug exposure.

Clinicopathological characteristics and survival outcomes of invasive lobular carcinoma in different races

To investigate the clinicopathological characteristics and to determine whether there is a differential effect of race and examine survival outcomes according to race, 18,295 breast invasive lobular carcinoma (ILC) patients were identified in the Surveillance, Epidemiology, and End Result (SEER) database, which includes White patients (n=15,936), Black patients (n=1,451) and patients of other races (including American Indians/Alaskan Natives and Asian/Pacific Islanders) (n=908). The Black ILC patients presented a higher rate of advanced histological grades and American Joint Committee on Cancer (AJCC) stages, a higher rate of lymph node (LN) involvement and a lower rate of progesterone receptors (PR)-positivity than the White patients and other races. The five-year overall survival (OS) and five-year breast cancer specific survival (BCSS) were worst in the Black patients among these patients (85.5%, 76.0% and 87.7%, P<0.01; 91.1%, 84.4% and 91.6%, P<0.01). Multivariate regression analyses were performed to determine the risk hazards ratios (HR) of death for patients of the White, Black and other races. Among these patients, the Black patients had the worst survival outcomes in five-year OS and BCSS outcomes (HR=1.35, 95% confidence interval (CI) :1.20-1.51, P<0.01; HR=1.39, 95%CI:1.21-1.61, P<0.01, respectively). After a 1:1:1 matching of the three groups, the Black patients still presented worse survival outcomes in BCSS compared to White patients (HR=1.88, 95%CI: 1.14-3.10, P=0.013), however, there was no difference in OS (HR=1.35, 95%CI: 0.93-1.96, P=0.111). Difference in outcomes may partially explained by difference in histological grades, AJCC stage, LN and PR status among the three groups. In conclusion, this study revealed that the Black patients had worse five-year OS and BCSS than White and other race patients.

Mixed invasive ductal and lobular carcinoma has distinct clinical features and predicts worse prognosis when stratified by estrogen receptor status

In order to investigate clinicopathological characteristics and prognosis of mixed invasive ductal and lobular carcinoma (IDC-L), 209,109 primary breast cancer patients diagnosed with invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC) or IDC-L were included. It was found that IDC-L patients had lower tumor grade and higher hormone receptor positive proportions than IDC patients. Moreover, IDC-L patients were younger and had a similar hormone receptor status compared with ILC patients. Kaplan-Meier plots showed that the breast cancer-specific survival (BCSS) of IDC-L patients was significantly better than IDC patients (P < 0.001) and tended to be better than ILC patients (P = 0.166). However, after adjusting for clinicopathological factors, survival advantage of IDC-L disappeared. Subgroup analysis indicated that IDC-L had higher hazard ratios (HRs) than IDC in grade 1, grade 2, ER-positive and ER-negative subgroups. Survival analysis in ER-positive and ER-negative subgroups showed that IDC-L predicted a worse prognosis than IDC. In conclusion, IDC-L is a distinct histological subtype compared with IDC and ILC. Lower grade and higher ER-positive proportions mainly contribute to its better prognosis. In both ER-positive and ER-negative subgroups, IDC-L predicts worse prognosis than IDC, which suggested the inadequacy of IDC-based therapy and the need of escalated therapy.