Pathologic complete response and survival in HER2-low and HER2-zero early breast cancer treated with neoadjuvant chemotherapy

The impact of carboplatin on pathologic complete response and survival based on HER2 low and HER2 zero status in triple negative breast cancer patients receiving neoadjuvant chemotherapy: a multicenter real-world analysis

BACKGROUND AND OBJECTIVES

Triple-negative breast cancer (TNBC) has a poor prognosis, and neoadjuvant chemotherapy (NACT) is the standard treatment for locally advanced TNBC. In this study, we aimed to evaluate the efficacy of adding carboplatin to NACT regarding pathological complete response (pCR) and survival in the HER2-low and HER2-zero subgroups of TNBC patients.

MATERIALS AND METHODS

The study included 269 patients from five medical oncology clinics. Patients were divided into two groups: HER2-low (n = 152, 56.5%) and HER2-zero (n = 117, 43.5%). Among HER2-zero patients, 30 (25.6%) received carboplatin, while 38 (25.0%) HER2-low patients received carboplatin. The benefit of adding carboplatin to NACT regarding pCR and survival was assessed in both HER2-zero and HER2-low groups.

RESULTS

When patients were evaluated according to HER2 status, the pCR rates were significantly higher in the HER2-zero group compared to the HER2-low group (45.2% versus 23.7%, p < 0.001). In the HER2-zero group, patients who received carboplatin had significantly higher pCR rates (63.3% versus 39.0%, p = 0.021). Similarly, in the HER2-low group, adding carboplatin significantly increased the pCR rates (36.8% versus 19.3%, p = 0.028). While carboplatin improved pCR rates in both HER2 subgroups, this benefit was not observed in patients with Grade 1 tumors, HER2 score 2-FISH negative tumors, or based on BRCA mutation status. Patients with pCR exhibited significantly prolonged DFS and OS (p = 0.002, p < 0.001, respectively).

CONCLUSIONS

Our research demonstrates that the addition of carboplatin increases pCR rates in both HER2-zero and HER2-low patient cohorts. We suggest that carboplatin should be considered as an addition to standard neoadjuvant chemotherapy for eligible TNBC patients, regardless of HER2-zero or HER2-low status, when appropriate based on individual patient factors and toxicity considerations.

Comprehensive analysis of HER2 Low Breast Cancer Response to Neoadjuvant Chemotherapy, a Retrospective Cohort Study

BACKGROUND

This study aimed to identify the response and survival outcomes of HER2-low patients following neoadjuvant chemotherapy (NAC).

METHOD

A retrospective cohort of patients who received NAC in the Department of Breast Surgery at Peking Union Medical College Hospital (PUMCH) from September 27, 2016, to January 23, 2024, was reviewed. Multivariate logistic regression and Cox proportional hazards models were used to identify factors associated with pathological complete response (pCR) and survival outcomes. The Kaplan-Meier method was applied to compare survival outcomes between HER2-zero and HER2-low patients.

RESULT

Four hundred and twenty-one patients meeting the inclusion criteria. The pCR rate of HER2-zero patients was significantly higher than that of HER2-low patients after adjusting for confounders (OR = 2.83, 95% CI: 1.44-5.65, adjusted P = .003). HER2-low patients demonstrated the most stable status after NAC within the hormone receptor (HR)-positive subset (80.82%) and the most unstable status within the HR-negative subset (57.69%). HER2-zero status was associated with worse disease-free survival (DFS) (HR = 1.94, 95% CI: 1.13-3.32, adjusted P = .02), but not with overall survival (OS) (HR = 1.18, 95% CI: 0.59-2.37, P = .65). HER2-zero patients had significantly worse DFS than HER2-low patients in the entire cohort (P = .014) and the HR-positive subset (P < .001). pCR could serve as a surrogate endpoint of favorable survival outcomes for HER2-zero patients, but not for HER2-low patients.

CONCLUSION

HER2-low patients might exhibit distinct characteristics compared with HER2-zero patients following NAC. Further multicenter, prospective studies are warranted to validate the conclusions of this exploratory research and assess whether HER2-low expression could serve as a new clinical subtype for evaluating NAC treatment outcomes.

Pathologic response rates in HER2-low versus HER2-zero early breast cancer patients receiving neoadjuvant therapy: a systematic review and meta-analysis

BACKGROUND

Currently, the primary methods for detecting HER2 expression levels are immunohistochemistry (IHC) and in situ hybridization (ISH), with the traditional standard being a HER2-positive score of 3 + accompanied by ERBB2 gene amplification detected through ISH. However, a new entity has recently emerged: HER2-low, defined as HER2 IHC 1 + or 2 + with negative ISH. HER2-low breast cancer, representing 45-60% of all HER2-negative tumors, has distinct biological characteristics and uncertain responses to conventional HER2-targeted therapies. Recent studies suggest varied clinical outcomes, highlighting the need for further investigation into the impact of HER2-low status on treatment efficacy and prognosis.

OBJECTIVE

This meta-analysis evaluates the difference in complete pathological response (pCR), disease-free survival (DFS), and overall survival (OS) between HER2-low and HER2-zero phenotypes.

METHODS

We systematically searched the main databases PubMed, Scopus, and Web of Science for articles evaluating women in neoadjuvant therapy expressing HER2-low and HER2-zero. We computed odds ratios (ORs) or hazard ratios (HRs) using DerSimonian and Laird random-effect models for all endpoints, with 95% confidence intervals (CIs). We assessed the heterogeneity using I2 statistics. R, version 4.2.3, was used for statistical analyses.

RESULTS

38 studies totaling 70,104 patients were included. The HER2-low group accounted for 61.3% of patients while HR + status represented 52.4% in the whole research. In 67,839 women, the pCR was analyzed, which in the overall cohort analysis favored the HER2-zero group (OR 0.84; 95% CI 0.78-0.90; p = 0.000005; I2 = 15%). Subgroup analyses for triple-negative breast cancer (TNBC) and HR + patients also favored HER2-zero expression, with an OR of 0.91 (95% CI 0.83-1.0; p < 0.041; I2 = 12%) and 0.75 (95% CI 0.70-0.81; p < 0.000001; I2 = 0%), respectively. In the multivariate analysis across all patients, both DFS and OS outcomes were significantly favorable for the HER2-low expression group, with HR 0.8317 (95% CI 0.7036-0.9832; p = 0.031) for DFS and HR 0.806 (95% CI 0.663-0.979; p = 0.03) for OS.

CONCLUSION

Based on our findings, HER2-zero status is associated with a significantly higher pathological complete response (pCR) rate compared to HER2-low in early-stage breast cancer, and other survival outcomes. These results suggest that HER2-zero should be considered a prognostic factor in early-stage breast cancer and taken into account in neoadjuvant treatment planning and future clinical research.

Strategies for the treatment of hormone receptor-positive HER2-low breast cancer based on clinical practice: a round table discussion

Human epidermal growth factor receptor 2 (HER2)-low breast cancer is a newly identified targetable subset of breast tumors, and its clinical characteristics and treatment strategies are controversial. The emergence of novel anti-HER2 antibody-drug conjugate (ADC) has brought promising approaches for HER2-low breast cancer treatment. Several clinical trials have validated the efficacy and safety of trastuzumab deruxtecan (T-Dxd) in HER2-low breast cancer at different treatment settings. The treatment timing, candidate identification, long-term management, and overcoming drug resistance are crucial questions to improve breast cancer patient survival. Here we present a clinical case of hormone receptor-positive (HR+) HER2-low breast cancer patient who experienced neoadjuvant chemotherapy, surgery, adjuvant, and first-line endocrine therapy with limited effectiveness. After the treatment failure of CDK4/6 inhibitors, the utilization of T-Dxd brought a long-term disease response and tolerable low toxicities. In this round table discussion, we summarized opinions and recommendations from breast cancer surgeons and oncologists on treatment strategies for this patient. The discussion mainly focused on the precise diagnosis of HER2-low breast cancer, treatment design at different disease status, regimens selection according to drug response, strategies consideration for overcoming drug resistance and the management of adverse events in long-term survival. These opinions would provide critical insights to improve HER2-low breast cancer treatment and offer valuable suggestions for clinical practice.

The prognostic impact of Her2 status in early triple negative breast cancer: a Turkish Oncology Group (TOG) study

The studies evaluating the impact of Her2 levels in neoadjuvant setting have conflicting data. The aim of the study was to evaluate the prognostic impact of Her2 status in early triple negative breast cancer(TNBC). In the study TNBC patients who were treated with neoadjuvant chemotherapy (NAC) and surgery were analyzed retrospectively. The primary aim of the study was to analyze the impact of Her2 status(Her2-0 and Her2-low) on pathological complete response (pCR). The secondary objectives were disease free survival (DFS) and overall survival (OS). 620 female triple negative breast cancer patients were evaluated. 427 patients (68.9%) had Her2-0 and 193(31.1%) had her2-low pathology. The pCR rates were similar between Her2-0 and Her2-low patients (33.0% vs. 27.5%, p = 0.098). Although Her2-0 group has better DFS (106 vs. 50 months, p = 0.002), in multivariate analysis it had a HR of 0.74 (p = 0.06). In addition, OS was similar (131 vs. 105 months, p = 0.13) with a HR of 0.88 (p = 0.61). In multivariate analysis; presence of LVI (HR:2.2 (95% CI 1.1-3.5) p = 0.001), Clinical stage T1/T2 (HR:0.39 (95% CI 0.2-0.6) p < 0.001) and lymph node negativity (HR:0.35 (95% CI 0.1-0.9) p = 0.03) were independent factors for OS. Although there were pathological and clinical differences, the pCR, DFS and OS were similar between Her2-0 and Her2-low TNBC patients. The importance of Her2 status of TNBC in neoadjuvant setting should be further studied.

The Omission of Anthracycline Chemotherapy in Women with Early HER2-Negative Breast Cancer-A Systematic Review and Meta-Analysis

BACKGROUND

Anthracycline-taxane is the standard chemotherapy strategy for treating high-risk early breast cancer despite the potentially life-threatening adverse events caused by anthracyclines. Commonly, the combination of docetaxel and cyclophosphamide (TC) is considered an alternative option. However, the efficacy of TC compared to anthracycline-taxane chemotherapy is unclear. This study compares disease-free survival (DFS), overall survival (OS) and cardiotoxicity between adjuvant TC and anthracycline-taxane for stages I-III, HER2-negative breast cancer.

METHODS

A systematic search on MEDLINE, Embase and Cochrane CENTRAL for randomized-controlled trials published until 11 March 2024, yielded 203 studies with 11,803 patients, and seven trials were included.

RESULTS

TC results in little to no difference in DFS (HR 1.09, 95% CI 0.98-1.20; moderate-certainty of evidence); OS (1.02, 95% CI 0.89-1.16; high-certainty of evidence); and cardiotoxicity (RR 0.54, 95% CI 0.16-1.76; high-certainty of evidence), compared to anthracycline-taxane. In the subgroup analysis, patients with ≥4 lymph nodes had improved DFS from anthracycline-taxane over TC.

CONCLUSIONS

Overall, there was no difference between TC and anthracycline-taxane in DFS, OS and cardiotoxicity. In women with ≥4 nodes, anthracycline-taxane was associated with a substantial reduction in relapse events, compared to TC. Our study supports the current standard of practice, which is to use anthracycline-taxane and TC chemotherapy as a reasonable option in select cases.

The emerging predictive and prognostic role of HER2 in HER2-negative early breast cancer: a retrospective study

PURPOSE

Many patients with early breast cancer (eBC) undergoing neoadjuvant chemotherapy do not achieve pathological complete response (pCR), which is a prognostic factor. We examined the role of HER2-low expression in predicting pCR and prognosis in HER2-negative eBC.

METHODS

We evaluated patients with stage I-III HER2-negative BC, treated between 2013 and 2023 at The Royal Marsden NHS Foundation Trust, London. Tumors were classified based on estrogen receptor (ER) status and into HER2-low and HER2-zero subgroups. We analyzed pCR rates, relapse-free survival (RFS) and overall survival (OS).

RESULTS

754 patients were included in the analysis. pCR rate was 8.9% in the ER+ /HER2-low, 16.5% in the ER+ /HER2-zero, 38.9% in the ER- ER-/HER2-low and 35.9% in the ER-/HER2-zero eBC (p < 0.001). Multivariable analysis showed a significantly lower pCR rate in HER2-low compared to HER2-zero BC in the ER+ subgroup. At a median follow-up of 63.8 months (59.9-67.4), we observed longer OS in HER2-low compared to HER2-zero patients in the overall and in the ER+ population. There was no predictive or prognostic impact of HER2-low status in the ER- population.

CONCLUSION

This study supports the interpretation of HER2 status as a possible prognostic and predictive biomarker for HER2-negative eBC, especially among patients with ER+ disease.

Neoadjuvant chemotherapy efficacy and prognosis in HER2-low and HER2-zero breast cancer patients by HR status: a retrospective study in China

Background

The promising efficacy of novel anti-HER2 antibody-drug conjugates (ADC) in HER2-low breast cancer has made HER2-low a research hotspot. However, controversy remains regarding the neoadjuvant chemotherapy (NAC) efficacy, prognosis, and the relationship with hormone receptor (HR) status of HER2-low.

Methods

A retrospective analysis was conducted on 975 patients with HER2-negative breast cancer undergoing NAC at Tianjin Medical University Cancer Institute and Hospital, evaluating pathological complete response (pCR) rate and prognosis between HER2-low and HER2-zero in the overall cohort and subgroups.

Results

Overall, 579 (59.4%) and 396 (40.6%) patients were HER2-low and HER2-zero disease, respectively. Compared with HER2-zero, the HER2-low cohort consists of more postmenopausal patients, with lower histological grade and higher HR positivity. In the HR-positive subgroup, HER2-low cases remain to exhibit lower histological grade, while in the HR-negative subgroup, they show higher grade. The HER2-low group had lower pCR rates than the HER2-zero group (16.4% vs. 24.0%). In the HR-positive subgroup, HER2-low consistently showed lower pCR rate (8.1% vs. 15.5%), and served as an independent suppressive factor for the pCR rate. However, no significant difference was observed in the pCR rates between HER2-low and HER2-zero in the HR-negative breast cancer. In the entire cohort and in stratified subgroups based on HR and pCR statuses, no difference in disease-free survival were observed between HER2-low and HER2-zero.

Conclusions

In the Chinese population, HER2-low breast cancer exhibits distinct characteristics and efficacy of NAC in different HR subgroups. Its reduced pCR rate in HR-positive subgroup is particularly important for clinical decisions. However, HER2-low is not a reliable factor for assessing long-term survival outcomes.

Clinicopathological characteristics and value of HER2-low expression evolution in breast cancer receiving neoadjuvant chemotherapy

OBJECTIVE

The present study aimed to evaluate the clinicopathological characteristics and value of HER2-low expression evolution in breast cancer receiving neoadjuvant chemotherapy (NAC).

METHODS

Patients with HER2 negative breast cancer receiving NAC from January 2017 to December 2020 were enrolled in this study. The clinicopathological characteristics, response to NAC, evolution of HER2 and prognostic value were retrospectively analyzed.

RESULTS

410 patients were included. The proportion of HR positive disease in HER2-low cases was higher than in HER2-zero population (75.8 % vs. 65.8 %, P = 0.040). No statistical significant difference in pCR rate was observed between HER2-low and HER2-zero patients (33.8 % vs. 39.3 %, P = 0.290) when pCR was defined as ypTis/0ypN0. Exploratory analysis revealed that the pCR rate of HER2-low cases was significantly lower than HER2-zero patients in the entire population (19.8 % vs. 33.3 %, P = 0.004) and HR positive population (12.6 % vs. 29.9 %, P = 0.001) when pCR was defined as ypT0ypN0. The evolution rate of HER2 expression after NAC was 31.0 % in HER2-zero patients and 24.7 % in HER2-low patients. Compared with patients with HR positive disease, patients with TNBC had higher evolution rate of HER2 expression after NAC (37.7 % vs. 23.6 %). Significant association was observed between HER2 evolution with histology type and Ki-67 index in HER2-zero patients and with lymph node involvement, HR status and Ki-67 index in HER2-low patients. Prognostic impact of HER2 evolution was not observed.

CONCLUSIONS

HR positive and HR negative HER2-low breast cancer exhibit different clinicopathological features, response to NAC and HER2 evolution after treatment.