Risk factors for recurrence after 5-year endocrine therapy in postoperative breast cancer patients

Objective To evaluate recurrence risk factors in postoperative breast cancer patients after 5-year adjuvant endocrine therapy. Methods From Jan 2006 to Dec 2011, a total of 327 patients were enrolled for this study. Kaplan-Meier curves were applied to estimate survival rates and COX′s proportional hazards model to identify prognostic variables. Results Among these 327 eligible patients, 42 (12.8%) patients suffered from distant metastasis and 34 (10.4%) patients experienced locoregional recurrence after 5-year adjuvant endocrine therapy. Survival analysis showed that patients with histologic grade 3 disease, lymph node metastasis, Ki-67 high expression, high TNM stage and radiotherapy were statistically significant with poorer relapse-free survival (RFS, P=0.000, 0.003, 0.000, 0.003, 0.034) and poorer distant metastasis-free survival (DMFS, P=0.000, 0.002, 0.000, 0.002, 0.023), respectively. In multivariate analysis, patients with histological grade 3 disease (P=0.002) and more than 3 positive nodes (P=0.032) were risk factors for lower RFS. However, only histological grade 3 (P=0.015) was risk factor for DMFS. Conclusions Late relapse after completion of 5-year adjuvant endocrine therapy was still common, patients with grade 3 disease and more than 3 positive nodes may benefit from extended endocrine therapy. Key words: Breast neoplasms; Prognosis; Endocrine therapy; Molecular subtype