Comparison of the pCR Rate and DFS Among Breast Cancer Patients with Different Hormone Receptor and HER2 Statuses

Abstract

Background

Recent studies have investigated the features of breast cancer (BC) with low human epidermal growth factor receptor 2 (HER2) expression or HER2-0 expression. However, the results were inconsistent. In this study, we investigated the differences in the pathological complete response (pCR) rate and disease-free survival (DFS) between HER2-low and HER2-0 BC patients and between subgroups.

Methods

HER2-negative BC patients who received neoadjuvant chemotherapy between January 2013 and December 2019 in our hospital were retrospectively reviewed. First, the pCR rate and DFS were compared between HER2-low and HER2-0 patients and among different hormone receptor (HR) and HER2 statuses. Subsequently, DFS was compared between different HER2 status populations with or without pCR. Finally, a Cox regression model was used to identify the prognostic factors.

Results

Overall, 693 patients were selected: 561 were HER2-low, and 132 were HER2-0. Between the two groups, there were significant differences in N stage (P = 0.008) and HR status (P = 0.007). No significant difference in the pCR rate (12.12% vs 14.39%, P = 0.468) or DFS was observed, independent of HR status. HR+/HER2-low patients had a significantly worse pCR rate (P < 0.001) and longer DFS (P < 0.001) than HR-/HER2-low or HER2-0 patients. In addition, a longer DFS was found in HER2-low patients versus HER2-0 patients among those who did not achieve pCR. Cox regression showed that N stage and HR status were prognostic factors in the overall and HER2-low populations, while no prognostic factor was found in the HER2-0 group.

Conclusion

This study suggested that HER2 status is not associated with the pCR rate or DFS. Longer DFS was found only among patients who did not achieve pCR in the HER2-low versus HER2-0 population. We speculated that the interaction of HR and HER2 might have played a crucial role in this process.

Keywords:

• HER2-low
• HER2-0
• hormone receptor
• pCR
• DFS

Data Sharing Statement

The data are available and can be requested from the corresponding author.

Ethics Approval and Informed Consent

This retrospective study was approved by the ethics committee of the First Affiliated Hospital of Chongqing Medical University (ID: No. 2020–59) and was performed according to the Declaration of Helsinki. And informed consent has been obtained from the study participants prior to study commencement. We declared that patient data was maintained with confidentiality.

Acknowledgments

The authors thank Dr. Yang Peng for his kindly help in the statistical analysis.

Author Contributions

All authors made a significant contribution to the work reported, whether in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Additional information

Funding

This work was supported by the Key Research and Development Project of Chongqing’s Technology Innovation and Application Development Special Big Health Field (Grant no. CSTC2021jscx-gksb-N0027), and the First-class Discipline Construction Project of Clinical Medicine in the First Clinical College of Chongqing Medical University (Grant no. 472020320220007).