Prognostic value of hormone receptor status conversion following neoadjuvant chemotherapy in a series of operable breast cancer patients.

Background: To investigate the prognostic value of hormone receptor (HR) status conversion after neoadjuvant chemotherapy (NAC) in patients with primary breast cancer.
Methods: 267 stage II-III breast cancer patients treated with NAC who had residual disease in the breast after NAC were retrospectively studied. The patients were divided into four groups based on the HR status: Group A, patients with HR-positive both before and after NAC; Group B, patients with HR status positive-to-negative change; Group C, patients with HR status negative-to-positive change; Group D, patients with HR-negative both before and after NAC. Patients with positive HR status (regardless of before or after NAC) were treated with adjuvant endocrine therapy, and a survival analysis was performed.
Results: In total, 15.7% of patients had HR status change after NAC. progression-free survival (PFS) in Group A was similar to that in Group C (hazard ratio, 1.16; P = 0.652), but that in Group B was significantly lesser than that in Group A (hazard ratio, 6.88; P = 0.001), and that in Group C was significantly longer than that in Group D (hazard ratio, 6.88; P = 0.001). A similar pattern of results was obtained for overall survival (OS).
Conclusions: The switch of HR status after NAC is remarkable for breast cancer. An HR switch may identify patients who would benefit from adjuvant endocrine therapy and impact the long-term outcome.