[Efficacy of adjuvant endocrine therapy in breast cancer patients with a positive-to-negative switch of hormone receptor status after neoadjuvant chemotherapy].

To evaluate the efficacy of adjuvant endocrine therapy (AET) in breast cancer patients with a positive-to-negative switch of hormone receptor status after neoadjuvant chemotherapy (NAC). One hundred and six patients who presented with hormone receptor (HR)-positive breast cancer at diagnosis and turned to HR-negative after NAC during December 2000 and December 2013 in Jiaxing Maternity and Child Health Care Hospital were retrospectively identified. Kaplan-Meier analysis and log-rank test were used for univariate analyses of factors related to disease free survival (DFS) and overall survival (OS). Multivariate analysis was carried out using the Cox proportional hazards model in patients with DFS and OS. All the patients were categorized into two groups on the basis of the administration of AET:61 AET-administered patients (57.5%) and 45 AET-naïve patients (42.5%). After a median follow-up of 68 months (range 14-103 months), human epidermal growth factor receptor 2 (HER-2) status, initial clinical stage, pathological axillary lymph node status and the use of AET were identified as the variables affecting DFS and OS (all <0.05). Patients treated with AET had a significantly improved 5-year DFS rate when compared with that without AET (77.1% 53.5%,<0.05). The 5-year OS of AET-administered patients was also better than that of AET-naïve patients (80.9% 71.0%,<0.05). Cox regression analysis showed that AET-administered or not was the independent predictor for 5-year DFS (=2.096, 95% :1.081-4.065, <0.05). Patients with HR altered from positive to negative after NAC may still gain benefit from AET.