Complete pathologic response rate to neoadjuvant chemotherapy increases with increasing HER2/CEP17 ratio in HER2 overexpressing breast cancer: analysis of the National Cancer Database (NCDB)

Differences in treatment response and survival between HER2(2+)/FISH-positive and HER2(3+) breast cancer patients after dual-target neoadjuvant therapy: a matched case-control study

Background

The efficacy of neoadjuvant therapy (NAT) comprising dual-target drugs has been confirmed among patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC). Therefore, we explored the differences in responses to NAT and prognosis between patients with HER2(3+) and HER2(2+)/fluorescence in-situ hybridization (FISH)-positive BC after TCbHP-based dual-target NAT.

Methods

Data from patients with HER2-positive invasive BC who underwent NAT and radical surgery between January 2019 and December 2022 at the Peking University First Hospital and Cancer Hospital of Chinese Academy of Medical Sciences were retrospectively summarized. Propensity score matching (PSM) was used to reduce confounding effects. Pathological complete response (pCR) and invasive disease-free survival (IDFS) were evaluated to respectively reflect therapeutic response and patients' survival status.

Results

We selected 132 BC patients (66 pairs) through PSM form a cohort of 308 patients. The pCR rate of patients in the HER2(3+) group was significantly higher than that in the HER2(2+)/FISH-positive group after NAT (P<0.001). Univariate and multivariate logistic regression analyses determined that pCR was significantly affected by tumor grade, hormone receptor (HR) status, HER2 status (P<0.05). The 3-year IDFS rate of HER2(3+) BC patients was better than that of HER2(2+)/FISH-positive BC patient (P=0.083), although the difference was not statistically significant. Furthermore, multivariable Cox regression analysis exhibited that positive lymph node, HER2(3+), and pCR were independent prognostic factors for IDFS.

Conclusion

HER2(2+)/FISH-positive BC patients exhibited worse treatment response and prognosis than HER2(3+) BC patients after dual-target NAT, indicating that HER2 expression level is a crucial factor influencing the therapeutic efficacy and prognosis of BC patients after TCbHP-based dual-target NAT.

Analysis of Factors Associated With Pathological Complete Response in Patients With HER2-Positive Breast Cancer Receiving Neoadjuvant Chemotherapy

PURPOSE

This study aimed to examine the impact of the level of HER2 overexpression on pathologic and clinical outcomes in HER2-positive breast cancer (BC) patients treated with neoadjuvant therapy (NAT).

METHODS

Women with Stage II or III HER2-positive BC who received anthracycline-taxane-trastuzumab NAT regimens followed by curative-intent surgery were included. Patients were classified according to tumor HER2 expression into HER2-high (immunohistochemistry (IHC) 3+ or fluorescence in situ hybridization (FISH) HER2/CEP17 ratio ≥5 or HER2 copy number ≥10) and HER2-intermediate (IHC 2+ with HER2/CEP17 ratio ≥2 to <5 or copy number ≥4 to <10). Univariate and multivariate logistic regression analyses were performed using HER2 expression as a categorical variable. The primary outcome was pathological complete response (pCR). Estimated 3-year disease-free survival (DFS) and Overall Survival (OS) were secondary outcomes.

RESULTS

Among 161 patients with HER2-positive BC, 139 (86%) and 22 (14%) were classified as HER2-high and HER2-intermediate, respectively; 105 (65.2%) had hormone receptor (HR)-positive tumors; 72 (45%) achieved a pCR. In the overall population, pCR rates of 18% and 49% were achieved in HER2-intermediate and HER2-high cases, respectively (odds ratio [OR] = 0.23 95% CI 0.07-0.72; P = .007). No pCRs were observed among HR-positive, HER2-intermediate cases. Estimated 3-year DFS was 97.1% versus 89.3% for patients achieving a pCR versus those with residual disease, respectively (P = .0011).

CONCLUSION

We found that patients with HER2-high disease were more likely to achieve pCR after NAT compared to patients with HER2-intermediate BC, a subgroup of patients that may benefit from more personalized NAT strategies.

Predicting pathologic complete response to neoadjuvant chemotherapy in breast cancer using a machine learning approach

BACKGROUND

For patients with breast cancer undergoing neoadjuvant chemotherapy (NACT), most of the existing prediction models of pathologic complete response (pCR) using clinicopathological features were based on standard statistical models like logistic regression, while models based on machine learning mostly utilized imaging data and/or gene expression data. This study aims to develop a robust and accessible machine learning model to predict pCR using clinicopathological features alone, which can be used to facilitate clinical decision-making in diverse settings.

METHODS

The model was developed and validated within the National Cancer Data Base (NCDB, 2018-2020) and an external cohort at the University of Chicago (2010-2020). We compared logistic regression and machine learning models, and examined whether incorporating quantitative clinicopathological features improved model performance. Decision curve analysis was conducted to assess the model's clinical utility.

RESULTS

We identified 56,209 NCDB patients receiving NACT (pCR rate: 34.0%). The machine learning model incorporating quantitative clinicopathological features showed the best discrimination performance among all the fitted models [area under the receiver operating characteristic curve (AUC): 0.785, 95% confidence interval (CI): 0.778-0.792], along with outstanding calibration performance. The model performed best among patients with hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) breast cancer (AUC: 0.817, 95% CI: 0.802-0.832); and by adopting a 7% prediction threshold, the model achieved 90.5% sensitivity and 48.8% specificity, with decision curve analysis finding a 23.1% net reduction in chemotherapy use. In the external testing set of 584 patients (pCR rate: 33.4%), the model maintained robust performance both overall (AUC: 0.711, 95% CI: 0.668-0.753) and in the HR+/HER2- subgroup (AUC: 0.810, 95% CI: 0.742-0.878).

CONCLUSIONS

The study developed a machine learning model ( https://huolab.cri.uchicago.edu/sample-apps/pcrmodel ) to predict pCR in breast cancer patients undergoing NACT that demonstrated robust discrimination and calibration performance. The model performed particularly well among patients with HR+/HER2- breast cancer, having the potential to identify patients who are less likely to achieve pCR and can consider alternative treatment strategies over chemotherapy. The model can also serve as a robust baseline model that can be integrated with smaller datasets containing additional granular features in future research.

Whole-exome profiles of inflammatory breast cancer and pathological response to neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant chemotherapy (NACT) became a standard treatment strategy for patients with inflammatory breast cancer (IBC) because of high disease aggressiveness. However, given the heterogeneity of IBC, no molecular feature reliably predicts the response to chemotherapy. Whole-exome sequencing (WES) of clinical tumor samples provides an opportunity to identify genomic alterations associated with chemosensitivity.

METHODS

We retrospectively applied WES to 44 untreated IBC primary tumor samples and matched normal DNA. The pathological response to NACT, assessed on operative specimen, distinguished the patients with versus without pathological complete response (pCR versus no-pCR respectively). We compared the mutational profiles, spectra and signatures, pathway mutations, copy number alterations (CNAs), HRD, and heterogeneity scores between pCR versus no-pCR patients.

RESULTS

The TMB, HRD, and mutational spectra were not different between the complete (N = 13) versus non-complete (N = 31) responders. The two most frequently mutated genes were TP53 and PIK3CA. They were more frequently mutated in the complete responders, but the difference was not significant. Only two genes, NLRP3 and SLC9B1, were significantly more frequently mutated in the complete responders (23% vs. 0%). By contrast, several biological pathways involved in protein translation, PI3K pathway, and signal transduction showed significantly higher mutation frequency in the patients with pCR. We observed a higher abundance of COSMIC signature 7 (due to ultraviolet light exposure) in tumors from complete responders. The comparison of CNAs of the 3808 genes included in the GISTIC regions between both patients' groups identified 234 genes as differentially altered. The CIN signatures were not differentially represented between the complete versus non-complete responders. Based on the H-index, the patients with heterogeneous tumors displayed a lower pCR rate (11%) than those with less heterogeneous tumors (35%).

CONCLUSIONS

This is the first study aiming at identifying correlations between the WES data of IBC samples and the achievement of pCR to NACT. Our results, obtained in this 44-sample series, suggest a few subtle genomic alterations associated with pathological response. Additional investigations are required in larger series.

The Predictive Role of Radiomics in Breast Cancer Patients Imaged by [18F]FDG PET: Preliminary Results from a Prospective Cohort

BACKGROUND

Recently, radiomics has emerged as a possible image-derived biomarker, predominantly stemming from retrospective analyses. We aimed to prospectively assess the predictive role of [18F]FDG-PET radiomics in breast cancer (BC).

METHODS

Patients affected by stage I-III BC eligible for neoadjuvant chemotherapy (NAC) staged with [18F]FDG-PET/CT were prospectively enrolled. The pathological response to NAC was assessed on surgical specimens. From each primary breast lesion, we extracted radiomic PET features and their predictive role with respect to pCR was assessed. Uni- and multivariate statistics were used for inference; principal component analysis (PCA) was used for dimensionality reduction.

RESULTS

We analysed 93 patients (53 HER2+ and 40 triple-negative (TNBC)). pCR was achieved in 44/93 cases (24/53 HER2+ and 20/40 TNBC). Age, molecular subtype, Ki67 percent, and stage could not predict pCR in multivariate analysis. In univariate analysis, 10 radiomic indices resulted in p < 0.1. We found that 3/22 radiomic principal components were discriminative for pCR. Using a cross-validation approach, radiomic principal components failed to discriminate pCR groups but predicted the stage (mean accuracy = 0.79 ± 0.08).

CONCLUSIONS

This study shows the potential of PET radiomics for staging purposes in BC; the possible role of radiomics in predicting the pCR response to NAC in BC needs to be further investigated.

Effect of HER2/CEP17 ratio on survival in metastatic HER2-positive gastric cancer, multicenter study

AIM

HER2-positive metastatic gastric cancer is still a highly fatal disease despite advances. We aimed to investigate the relationship between HER2/CEP17 ratio and survival in patients with HER2-positive metastatic gastric cancer.

METHODS

A total of 99 patients from 8 different centers in Turkey were included in the study. Patients with HER2-positive metastatic gastric cancer and whose HER2/CEP17 ratio was examined were included in the study. Patients were divided into two groups according to HER2/CEP17 values, and survival analysis was performed.

RESULTS

The median age was 64 (24-83) years. There were 74 (74.8%) male and 25 (25.2%) female patients. OS in the high HER2/CEP17 ratio group was 21.97 months (95% CI: 16.36-27.58), and in the low ratio group was 16.17 months (95% CI: 10.95-21.38) (p = 0.015). OS was 17.7 months (95% CI: 7.02-28.37) in the high HER2 gene copy number group and 10.13 months (5.55-14.71) in the group with low copy number (p = 0.03). PFS was 10.94 months (95% CI: 7.55-14.33) in the group with high HER2 gene copy number and 7.56 months (4.62-10.49) in the low copy number group (p = 0.06).

CONCLUSION

Patients with both high HER2 gene amplification and high HER2/CEP17 ratio had better OS. The PFS of the group with high HER2 gene amplification was also better. To our knowledge, this is the first study in the literature showing that the HER2/CEP17 ratio affects survival in patients with metastatic gastric cancer.

In situ HER2 RNA expression as a predictor of pathologic complete response of HER2-positive breast cancer patients receiving neoadjuvant chemotherapy and anti-HER2 targeted treatment

BACKGROUND

Immunohistochemistry (IHC) and in situ hybridization (ISH) remain standard biomarkers for therapeutic decisions in human epidermal growth factor 2 (HER2)-positive breast cancers (BCs); however, they are insufficient to explain the heterogeneous anti-HER2 response.

METHODS

We aimed to investigate the correlation of in situ HER2 RNA expression (isHRE), using RNAscope, with HER2 biomarkers and the impact of isHRE on the pathological complete response (pCR) rates of 278 patients with HER2 IHC/fluorescence ISH (FISH)-positive BC receiving neoadjuvant chemotherapy and anti-HER2 targeted treatment (NCTT).

RESULTS

We validated HER2 RNAscope scoring as a semiquantitative method to determine isHRE and showed a positive correlation between RNAscope scores and pCR rates, with particularly different rates between patients with a score of 5 versus 1-4 BCs (66.7% vs. 15.9%, p < 0.0001). There were higher RNAscope scores and pCR rates in patients with HER2 IHC 3 + versus IHC 2+/FISH + BCs and HER2 RNAscope scores and pCR rates showed similar non-linear positive correlations with HER2 copy numbers and HER2/centromere 17 ratios. Moreover, in each HER2-positive IHC/FISH category, higher pCR rates were observed in patients with RNAscope scores of 5 versus 1-4 BC. Patients achieving pCR had BCs with notably higher HER2 RNAscope scores. Multivariate analysis identified HER2 RNAscope 5 as a strong pCR predictor [odds ratio = 10.865, p < 0.001]. The combined impact of multivariate analysis-defined pCR predictors demonstrated that a higher pCR rate was observed in patients with a score of 5 versus a score of 1-4 BCs regardless of the status of hormone receptor and mono-or dual anti-HER2 blockade.

CONCUSIONS

Our results demonstrated that high isHRE (RNAscope score 5) is a strong pCR predictor in patients with HER2-positive BCs receiving NCTT, highlighting the complementary role of isHRE in stratifying HER2 status in tissue. Such stratification is relevant to anti-HER2 therapeutic efficacy, particularly using the cutoff of score 1-4 versus 5.

Correlation of In Situ HER2 RNA Expression With HER2 Immunohistochemistry and Fluorescence In Situ Hybridization Categories in Breast Cancer

CONTEXT.—

RNA sequencing study has demonstrated that human epidermal growth factor receptor 2 (HER2) RNA levels influence anti-HER2 therapeutic efficacy. However, in situ HER2 RNA expression (isHRE), which evaluates HER2 RNA expression in tissue, has remained unclear in breast cancers (BCs) of various HER2 immunohistochemistry (IHC)/in situ hybridization (ISH) categories.

OBJECTIVE.—

To correlate isHRE with all HER2 IHC/fluorescence ISH (FISH) categories in BC.

DESIGN.—

Formalin-fixed, paraffin-embedded tissue sections from 259 BCs, covering all IHC/FISH categories, were analyzed for isHRE by RNAscope.

RESULTS.—

We validated HER2 RNAscope scoring as a semiquantitative method to evaluate isHRE and demonstrated significantly higher RNAscope scores in IHC 3+ than in IHC 2+ cases, and in IHC 2+ than in IHC 0/1+ cases. Among the 5 IHC 2+/FISH groups, group 1 (G1) cases had the highest scores. The scores in G3 cases were higher than those in G2, but not significantly different from those in G4 and G5. G4 cases had significantly higher scores than those in G2. Higher HER2 copy numbers and HER2:CEP 17 (centromere 17) copy number ratios were significantly correlated with higher isHRE in G1 cases, but not in G2 to G5 cases. RNAscope scores were significantly lower in HER2-negative (IHC 0) than in HER2-low (IHC 2+/FISH- and IHC 1+) BCs but were not different between IHC 0 and 1+ BCs when analyzed separately.

CONCLUSIONS.—

We demonstrate the HER2 RNA expression status among BCs of various HER2 IHC/FISH categories in tissue. Such information may be relevant for anti-HER2 treatment decisions considering the role of HER2 RNA expression in predicting anti-HER2 therapeutic efficacy.

CNA Landscape of HER2-Negative Breast Cancer in Anthracycline-Based Neoadjuvant Chemotherapy Regimens

Critical evaluation of how and when to include anthracyclines in preoperative chemotherapy is becoming more relevant in an era when the molecular genetic approach not only allows for the development of biologically targeted therapeutics, but also implies the ability to select the patients likely to benefit from certain cytotoxic agents. Changes in the copy number aberration (CNA) landscape of luminal B HER2- negative (HER2-) breast cancer (BC) during anthracycline-based neoadjuvant chemotherapy (NAC) regimens were studied in order to identify groups of potential CNA markers of objective response and CNA markers for predicting the development of hematogenous metastasis. Comparison of CNA frequencies depending on the response to NAC showed that objective response was observed in a larger number of deletions in the 11q22.3 and 11q23.1 loci (p = 0.004). Comparison of CNA frequencies in groups of patients after treatment showed that hematogenous metastasis was observed with a greater number of amplifications in the 9p22.2 locus (p = 0.003) and with a greater number of deletions in the 9p21.3 locus (p = 0.03). Potential predictive CNA markers of objective response and prognostic CNA markers of hematogenous metastasis in anthracycline- based NAC regimens have been identified.

HER2 Amplification Level Predicts Pathological Complete Response in the Neoadjuvant Setting of HER2-Overexpressing Breast Cancer: A Meta-Analysis and Systematic Review

Anti-HER2 therapies have dramatically improved the prognosis of human epidermal growth factor receptor 2 (HER2)-overexpressing cancers. However, the correlation between the HER2 copy number and the response rate to anti-HER2 remains unclear. Here, following the PRISMA method, we performed a meta-analysis in the neoadjuvant setting in breast cancer to study the association between the HER2 amplification level and the pathological complete response (pCR) to anti-HER2 therapies. Nine articles (four clinical trials, five observational studies) were retrieved after full-text screening, involving 11,238 women with locally advanced breast cancer in the neoadjuvant setting. The median HER2/CEP17 ratio cut-off value was 5.0 ± 5.0 (min-max = 1.0-14.0). For the overall population, the median pCR rate was 48% using the random effect model. The studies were categorized in quartiles as follows: ≤2 (Class 1); 2.1 to 5.0 (Class 2); 5.1 to 7.0 (Class 3); and >7.0 (Class 4). After grouping, the pCR rates were 33%, 49%, 57%, and 79%, respectively. When we excluded the study by Greenwell et al., which accounted for 90% of the patients, using the same quartiles, we still observed an increasing rate of pCR as the HER2/CEP17 ratio increased. This is the first meta-analysis demonstrating the relationship between the HER2 amplification level and the percentage of pCR in the neoadjuvant setting among women with HER2-overexpressing breast cancer, with potential therapeutic applications.

Inhibiting the glycerophosphodiesterase EDI3 in ER-HER2+ breast cancer cells resistant to HER2-targeted therapy reduces viability and tumour growth

BACKGROUND

Intrinsic or acquired resistance to HER2-targeted therapy is often a problem when small molecule tyrosine kinase inhibitors or antibodies are used to treat patients with HER2 positive breast cancer. Therefore, the identification of new targets and therapies for this patient group is warranted. Activated choline metabolism, characterized by elevated levels of choline-containing compounds, has been previously reported in breast cancer. The glycerophosphodiesterase EDI3 (GPCPD1), which hydrolyses glycerophosphocholine to choline and glycerol-3-phosphate, directly influences choline and phospholipid metabolism, and has been linked to cancer-relevant phenotypes in vitro. While the importance of choline metabolism has been addressed in breast cancer, the role of EDI3 in this cancer type has not been explored.

METHODS

EDI3 mRNA and protein expression in human breast cancer tissue were investigated using publicly-available Affymetrix gene expression microarray datasets (n = 540) and with immunohistochemistry on a tissue microarray (n = 265), respectively. A panel of breast cancer cell lines of different molecular subtypes were used to investigate expression and activity of EDI3 in vitro. To determine whether EDI3 expression is regulated by HER2 signalling, the effect of pharmacological inhibition and siRNA silencing of HER2, as well as the influence of inhibiting key components of signalling cascades downstream of HER2 were studied. Finally, the influence of silencing and pharmacologically inhibiting EDI3 on viability was investigated in vitro and on tumour growth in vivo.

RESULTS

In the present study, we show that EDI3 expression is highest in ER-HER2 + human breast tumours, and both expression and activity were also highest in ER-HER2 + breast cancer cell lines. Silencing HER2 using siRNA, as well as inhibiting HER2 signalling with lapatinib decreased EDI3 expression. Pathways downstream of PI3K/Akt/mTOR and GSK3β, and transcription factors, including HIF1α, CREB and STAT3 were identified as relevant in regulating EDI3 expression. Silencing EDI3 preferentially decreased cell viability in the ER-HER2 + cells. Furthermore, silencing or pharmacologically inhibiting EDI3 using dipyridamole in ER-HER2 + cells resistant to HER2-targeted therapy decreased cell viability in vitro and tumour growth in vivo.

CONCLUSIONS

Our results indicate that EDI3 may be a potential novel therapeutic target in patients with HER2-targeted therapy-resistant ER-HER2 + breast cancer that should be further explored.

Hypoxia-Inducible Factor-1 Alpha Expression Is Predictive of Pathological Complete Response in Patients with Breast Cancer Receiving Neoadjuvant Chemotherapy

Simple Summary

Standard neoadjuvant chemotherapy, based on taxanes and anthracyclines, makes conservative treatment of breast cancer possible and it allows for the evaluation of the tumor response in terms of achieving pathological complete response. Whereas hypoxia participates in carcinogenesis, resulting in less differenced tumor cells and poorer prognosis, HIF-1α could be predictive of the tumor response to treatment. Nonetheless, very few studies have evaluated the predictive value of HIF-1α in breast cancer in patients receiving neoadjuvant chemotherapy.

Abstract

To demonstrate the value of hypoxia-inducible factor-1α (HIF-1α) in predicting response in patients with breast cancer receiving standard neoadjuvant chemotherapy (NAC). Methods: Ninety-five women enrolled in two prospective studies underwent biopsies for the histopathological diagnosis of breast carcinoma before receiving NAC, based on anthracyclines and taxanes. For expression of HIF-1α, EGFR, pAKT and pMAPK, tumor samples were analyzed by immunohistochemistry in tissues microarrays. Standard statistical methods (Pearson chi-square test, Fisher exact test, Kruskal–Wallis test, Mann–Whitney test and Kaplan–Meier method) were used to study the association of HIF-1α with tumor response, survival and other clinicopathologic variables/biomarkers. Results: HIF-1α expression was positive in 35 (39.7%) cases and was significantly associated to complete pathological response (pCR) (p = 0.014). HIF-1α expression was correlated positively with tumor grade (p = 0.015) and Ki-67 expression (p = 0.001) and negativity with progesterone receptors (PR) (p = 0.04) and luminal A phenotype expression (p = 0.005). No correlation was found between HIF-1α expression and EGFR, pAKT and pMAPK. In terms of survival, HIF-1α expression was associated with a significantly shorter disease-free survival (p = 0.013), being identified as an independent prognostic factor in multivariate analysis. Conclusions: Overexpression of HIF-1α is a predictor of pCR and shorter DFS; it would be valuable to confirm these results in prospective studies.

Predicting Pathological Complete Response in Neoadjuvant Dual Blockade With Trastuzumab and Pertuzumab in HER2 Gene Amplified Breast Cancer

Background

Dual-targeted therapy is the standard treatment for human epidermal growth factor receptor 2 (HER2)-positive breast cancer, and effective biomarkers to predict the response to neoadjuvant trastuzumab and pertuzumab treatment need further investigation. Here, we developed a predictive model to evaluate the dual-targeted neoadjuvant treatment efficacy in HER2 gene-amplified breast cancer.

Method

This retrospective study included 159 HER2-amplified patients with locally advanced breast cancer who received neoadjuvant trastuzumab, pertuzumab, and chemotherapy. The correlation between clinicopathological factors and pathological complete response (pCR, in the breast and axilla) was evaluated. Patients were randomly assigned into the training set (n=110) and the testing set (n=49). We used an independent cohort (n=65) for external validation. We constructed our predictive nomogram model with the results of risk variables associated with pCR identified in the multivariate logistic analysis. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve, decision curve analysis, and calibration curves were employed to assess the nomogram's performance.

Results

We revealed that the HER2/CEP17 ratio (p=0.001), CD8 levels (p=0.005), and histological grade (p=0.007) were independent indicators for pCR in dual-targeted neoadjuvant treatment after multivariate adjustment. The combined prediction efficacy of the three indicators was significantly higher than that of each single indicator alone. The AUCs were 0.819, 0.773, and 0.744 in the training, testing, and external validation sets, respectively.

Conclusions

The HER2/CEP17 ratio, CD8 levels, and histological grade were significantly correlated with pCR in dual-targeted neoadjuvant treatment. The combined model using these three markers provided a better predictive value for pCR than the HER2/CEP17 ratio, CD8 levels, and the histological grade alone, which showed that an immunological effect partially mediates the predictive impact of neoadjuvant treatment.

Pathological examination of breast cancer samples before and after neoadjuvant therapy: recommendations from the Italian Group for the Study of Breast Pathology - Italian Society of Pathology (GIPaM-SIAPeC)

Neoadjuvant therapy (NAT) in breast cancer is administered to downstage the tumor, de-escalate surgery, and provide prognostic information that can be used to tailor subsequent adjuvant therapy. In this respect, the pathological evaluation of both pre-NAT biopsies and post-NAT surgical specimens is crucial to precisely assess the treatment response. With the increasing possibilities of NAT protocols and the rising number of eligible patients, it has become extremely important to standardize the pathological response assessment. Here, we provide an update on the recommendations of the Italian Group for the Study of Breast Pathology - the Italian Society of Pathology (GIPaM-SIAPeC) for the analysis of breast cancer samples before and after NAT.

Pathology after neoadjuvant treatment - How to assess residual disease

While systemic therapy for non-metastatic, invasive breast cancer is provided to minimize the risk of recurrence, neoadjuvant therapy (NAT) is given prior to surgery to downstage the tumor and to evaluate treatment response. Downstaging the tumor may allow for less invasive surgery on the breast and axilla, thus avoiding the need for breast reconstruction, improving cosmetic outcomes, and reducing postoperative complications. With the rising number of NAT candidates, it is becoming increasingly important to standardize how tumor response is assessed after surgery. In the post-NAT setting, macroscopic assessment of surgical samples, extent of sampling for histology, and microscopic analysis require a different approach than in the primary surgery setting. In the neo-adjuvant setting, the close collaboration of pathologists, oncologists, surgeons, and radiologists within the multidisciplinary team is essential to ensure the best possible management of breast cancer patients. Here, we provide an update on the suggested procedures for an accurate assessment of tumor response to NAT, including the evaluation of all relevant parameters that correlate with long-term prognosis and inform the subsequent adjuvant interventions.

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Neoadjuvant therapy (NAT) is given to downstage the tumor and evaluate treatment response.

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It is extremely important to standardize how NAT tumor response is assessed after surgery.

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A tailored approach is required for gross examination and microscopic analysis of both tumor and lymph nodes (either sentinel and axillary).

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Changes of biomarkers status (i.e. ER, PgR, Ki67, and HER2) can occur after NAT and biomarkers should always be re-assessed.

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Collaboration of pathologists, oncologists, surgeons, and radiologists is necessary for the appropriate clinical management.

Tumor-associated macrophages are associated with response to neoadjuvant chemotherapy and poor outcomes in patients with triple-negative breast cancer

Background and objective: Tumor-associated macrophages (TAMs) play an essential role in tumor progression and metastasis. However, the role of TAMs in neoadjuvant chemotherapy (NAC) is unclear and need to be identified. The main subject of this study was to investigate whether TAMs are related to the chemotherapeutic response with triple-negative breast cancers (TNBC).

Methods: We retrospectively analyzed pretreatment tissue from patients who received NAC and followed by a mastectomy or breast-conservation for stage II-III TNBC in this study. The association between TAMs and the pathological complete response (pCR) rate of TNBC to NAC was analyzed. In addition, the correlation of the TAMs with recurrence-free survival (RFS) in patients with TNBC was also evaluated.

Results: Of the 91 patients, 31 (34.1%) patients experienced pathological complete response (pCR) after completion of NAC. Regarding the chemotheraptic response, patients with low infiltration of CD163⁺ macrophages achieved a significantly higher rate of pCR. Importantly, Kaplan-Meier survival shown that patients with high infiltration of CD163⁺ macrophages and non-pCR had poor OS and RFS.

Conclusions: our data showed that TAMs may predict chemotherapeutic response and can be used as a promising prognostic candidate for poor survival in TNBC patients treated with NAC.

Association Between the HER2 Protein Expression Level and the Efficacy of Neoadjuvant Chemotherapy in HER2-Positive Breast Cancer

Objective

This study aimed to assess the relationship between human epidermal growth factor receptor-2 (HER2) protein expression level and clinicopathological features of HER2-positive breast cancer, and to analyze whether the expression level of HER2 protein could predict the response to anti-HER2 therapy.

Methods

The present study included 296 patients with HER2-positive breast cancer receiving neoadjuvant chemotherapy (NAC) containing trastuzumab between January 2014 and November 2019. The univariate comparisons of the differences in clinicopathological parameters between different HER2 protein expression groups, and the association between HER2 protein expression level and efficacy of NAC, were made using a X² test or Mann–Whitney U-test. Multivariate analyses of the differences in clinicopathological parameters between different HER2 protein expression groups, and the association between HER2 protein expression level and efficacy of NAC, were performed using logistic regression analysis.

Results

A total of 110 patients achieved a pathological complete response (pCR) after NAC. The pCR rate was 37.2%. The study showed that patients who were HR-negative, AR-positive, and CK5/6-negative had significantly higher expression level of HER2 protein [odds ratio (OR) = 0.183, P < 0.001; OR = 6.414, P = 0.004; OR = 0.261, P = 0.004, respectively]. Patients with HER2 3+ detected by immunohistochemistry (IHC) had significantly higher pCR rates compared with patients with HER2 2+. The HER2 protein expression level might effectively predict the efficacy of NAC in patients with HER2-positive breast cancer (OR = 3.520, P = 0.003).

Conclusion

The HER2 protein expression level was related to multiple clinical features in patients with HER2-positive breast cancer. For example, hormone receptor, androgen receptor, cytokeratin5/6, and HER2 protein expression level may be used to predict the response to NAC in patients with HER2-positive breast cancer and may serve as a predictive factor for NAC efficacy.

Neoadjuvant chemotherapy and HER2 dual blockade including biosimilar trastuzumab (SB3) for HER2-positive early breast cancer: Population based real world data from the Danish Breast Cancer Group (DBCG)

BACKGROUND

Dual blockade with trastuzumab and pertuzumab combined with neoadjuvant chemotherapy (NACT) has been increasingly used for HER2-positive tumours >2 cm and/or with positive axillary lymph nodes in order to evaluate pathologic response and obtain better surgical management. SB3 is a registered biosimilar trastuzumab approved following a phase III trial demonstrating similar efficacy in the neoadjuvant setting as trastuzumab. However, the study was done without pertuzumab.

METHOD

The database of the Danish Breast Cancer Group was used to extract data on all patients who started NACT with SB3 and pertuzumab between September 1, 2018 and August 31, 2019. The primary endpoint was pathological complete response (pCR) rate.

RESULTS

In total 215 patients received NACT and dual blockade. The median age was 55 (24-81). NACT used was cyclophosphamide and epirubicin followed by weekly paclitaxel (62% on six cycles, 35% on eight cycles) or other chemotherapy followed by weekly paclitaxel (3%). Overall, 56% of patients achieved pCR. 60 of 88 node-positive patients pre-NACT achieved ypN0(i-) after neoadjuvant treatment. pCR rate was significantly associated with estrogen receptor status and malignancy grade. An association with CEP17/HER2-ratio was assessed.

CONCLUSION

Real world data on dual blockade with SB3 and pertuzumab in combination with NACT in a nationwide population-based study show a pCR rate comparable to that seen in previous clinical studies.

Efficacy of Hyperthermia in Treatment of Recurrent Metastatic Breast Cancer After Long-Term Chemotherapy: A Report of 2 Cases

BACKGROUND Breast cancer has a long-term prognosis with various multimodality treatments. This report introduces the effectiveness of radiofrequency (RF) hyperthermia in the long-term treatment for recurrent/metastatic breast cancer. CASE REPORT In the first case, the patient had bone and liver metastases during the course of chemotherapy, hormone therapy, and radiotherapy for 27 years after curative resection of breast cancer. Finally, she received RF hyperthermia alone for liver metastasis and showed a decrease in tumor markers and reduction in liver metastasis on computed tomography (CT). In the second case, the patient underwent curative resection for multiple occurrences on the left side of the breast. She received postoperative chemotherapy combined with hormone therapy but had metachronous local recurrences. She continued hormone therapy after 2 local recurrence resections; unfortunately, she had bone, liver, and lung metastases and pleural dissemination. Eventually, the patient received RF hyperthermia combined with oral chemotherapy. Her tumor markers decreased, and CT showed disappearance of lung metastasis and improved pleural dissemination. Furthermore, the reduction of chemotherapy adverse events due to hyperthermia allowed the patient to continue chemotherapy and improved her quality of life. CONCLUSIONS We present 2 cases in which RF hyperthermia had a positive effect despite the presence of a recurrent tumor after various types of surgery, chemotherapy, and radiotherapy. This report suggests that the addition of RF hyperthermia to conventional multidisciplinary therapies may enhance the therapeutic effect of these treatments and improve the quality of life in patients with recurrent breast cancer.