Background: To investigate the prognostic value of positive-to-negative changes in hormone receptor (HR) status after neoadjuvant chemotherapy (NCT) in patients with HR-positive breast cancer.
Methods: Data from 224 stage II-III breast cancer patients with positive HR status before NCT who had residual disease in the breast after NCT were collected. HR status of the residual tumors was retested after NCT. A survival analysis was performed in 214 patients with adjuvant endocrine therapy regardless of post-NCT HR status. The survival analysis also examined other clinical and pathologic variables.
Results: In total, 15.2 % of patients had a positive-to-negative change in HR status after NCT, and this change was observed more frequently in HER-2-positive tumors than HER-2-negative tumors (P = 0.001). In 214 patients who had been treated with adjuvant endocrine therapy regardless of post-NCT HR status, the alteration in HR status was an independent factor for the prediction of a poorer disease-free survival (P = 0.026) and overall survival (P < 0.001) in the adjuvant endocrine therapy patients. The 5-year disease-free survival and overall survival rates were 43.5 % and 59.8 %, respectively, in patients with HR status conversion and 67.8 % and 82.5 %, respectively, in patients whose HR status remained positive (log rank test P = 0.003 and P = 0.001).
Conclusions: The switch of HR status after NCT is remarkable for HR-positive tumors. An HR-negative switch may identify patients who would benefit from alternative systemic therapies.