Long-term outcomes following adjuvant endocrine therapy in breast cancer patients with a positive-to-negative change of hormone receptor status following neoadjuvant chemotherapy.

The aim of the present study was to investigate whether breast cancer patients with changes from positive to negative in the hormone receptor following neoadjuvant chemotherapy (NAC) could benefit from adjuvant endocrine therapy (ET). Between December 2000 and November 2010, 97 eligible patients with a positive-to-negative switch of the hormone receptor status following NAC were identified. All the patients were categorized into two groups on the basis of the administration of ET: 57 ET-administered and 40 ET-naïve patients. Survival analyses were performed to examine the prognostic value of ET administration, as well as other clinical and pathological variables. The administration of ET was associated with a significantly improved disease-free survival (DFS) (P=0.018) in patients with a positive-to-negative switch of the hormone receptor status. The 5-year DFS rates were 77.0 and 55.5% in ET-administered and ET-naïve patients, respectively. The 5-year overall survival (OS) rate for ET-administered was also higher than that of the ET-naïve patients (81.3 vs. 72.7%, P=0.053), but the difference between the two groups did not reach a statistical significance. The present study revealed that patients with the hormone receptor that was altered from positive to negative following NAC benefit from ET, and the hormone receptor status should be evaluated not only in specimens obtained during post-NAC surgery, but also in specimens biopsied prior to NAC.