Exploring Real-World HER2-Low Data in Early-Stage Triple-Negative Breast Cancer: Insights and Implications

Abstract

Purpose

This study aimed to compare the clinical behavior, clinicopathological and sociodemographic characteristics of patients with early-stage triple-negative breast cancer (TNBC) who belong to the HER2-low and HER2-zero subgroups.

Patients and Methods

This study involved a thorough search in the internal database of a single Brazilian institution to identify women with TNBC who underwent neoadjuvant chemotherapy (NACT) followed by curative surgery within the period from January 2010 to December 2014. HER2 analysis through immunohistochemistry (IHC) and, if required, amplification by in situ hybridization, was conducted using core biopsy samples. The study assesses outcomes of residual cancer burden (RCB), event-free survival (EFS), and overall survival (OS).

Results

A total of 170 cases were analyzed, with a mean age of 51.4 years (standard deviation, SD 11.2). The HER2 status was categorized as IHC 0, 1+, or 2+ in 80 (47.1%), 73 (42.9%), and 17 (10%) patients, respectively. No significant differences were observed in the prevalence of clinical pathological characteristics among the subgroups. The absence of significant results for clinicopathological and demographic features hindered the multivariate analysis of HER2 subgroups. Similarly, no significant differences were found in the RCB, EFS, and OS outcomes between HER2 subgroups.

Conclusion

The findings of this study suggest that, in early-stage TNBC, the clinical behavior and survival outcomes of the HER2-low subgroup may not differ significantly from those of the HER2-zero subgroup.

Keywords:

• HER2 status
• HER2-low
• biomarker
• triple-negative breast cancer

Data Sharing Statement

The datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Ethical Approval

The current investigation was subjected to ethical scrutiny and received approval from the Ethics in Human Research Committee of INCA, Rio de Janeiro, Brazil, with registration number CAAE 61675516.9.0000.5274, adhering to the principles of Good Clinical Practice guidelines.

Informed Consent

Considering the retrospective nature of this observational study, which involved the use of anonymized data for analysis, the Institutional Review Board (IRB), also known as the Ethics in Human Research Committee of the National Cancer Institute (Comitê de Ética em Pesquisa do Instituto Nacional de Câncer; CEP-INCA), deemed it appropriate to waive the requirement for informed consent from participants.

Acknowledgments

The authors express their profound gratitude to all the patients and their families who demonstrated trust and willingness to participate in this study and provided invaluable biological samples for research purposes. They extend their thanks to Mrs. Isabele Avila Small for providing technical assistance with statistical analysis and to Andréa Rodrigues Cordovil Pires for her contribution in selecting images that represent the HER2 status.

Disclosure

The authors declare that they have no conflicts of interest.