Biomarker alteration following chemotherapy-based systemic therapy in de novo metastatic breast cancer

Abstract

Introduction

It is unclear whether the expression of biomarkers such as estrogen receptor (ER), progesterone receptor(PR), human epidermal growth factor receptor-2(HER2), and Ki-67 proliferation index changes following chemotherapy-based systemic therapy(CST) in patients with de novo metastatic breast cancer(dnMBC). The study aimed to investigate the expression of the biomarkers before and after CST and its impact on the prognosis of dnMBC patients.

Methods

Using hospital-based database, we conducted a retrospective cohort study on dnMBC patients who received CST between February 2010 and December 2017. Based on clinicopathological data, changes in pathological findings(ER,PR,HER-2,Ki-67) following CST were examined. The effect of biomarker conversion on prognosis was evaluated. The primary outcome was overall survival(OS). Kaplan-Meier method and log-rank test was used for survival analyses.

Results

The study included 192 female patients. The change rates of ER,PR,HER-2 and Ki-67 before and after CST were 9.9 %,17.2 %,6.2 % and 25.5 % respectively. Among them, the change in negative-to-positive expression of Ki-67 was the most common type of discordance observed. There was no statistical difference in OS between patients with changes in the four biomarkers and patients with no changes in the biomarkers(all p > 0.05). Interestingly, positive conversion of ER and PR, as well as persistent positive HER2 and Ki-67, were significantly associated with poor prognosis(p < 0.001,p < 0.001; p = 0.029,p < 0.001). Family history, initial metastatic site, and tumor grade were independent variables related to survival(p = 0.002,p < 0.001,p < 0.001).

Conclusions

Changes in ER, PR, HER2, and Ki-67 status were observed in patients following CST. Positive conversion of ER and PR, and persistent positive expression of HER2 and Ki-67 may indicate a poor prognosis. Further research is needed to determine whether biomarker expression investigations are needed following CST to optimize treatment options and improve survival.