ER-positive breast cancer patients with more than three positive nodes or grade 3 tumors are at high risk of late recurrence after 5-year adjuvant endocrine therapy

PURPOSE: Currently, although several clinical trials available give strong suggestions that extension of endocrine therapy has benefits, the risk level at which patients may benefit from extended endocrine therapy remains uncertain. This study aimed to identify the proportion of patients at a substantial risk of late recurrence after 5-year adjuvant endocrine therapy. PATIENTS AND METHODS: We reviewed 1,056 female patients with primary breast cancer who underwent curative resection between January 2006 and December 2011. Univariate and multivariate analyses were performed using the Cox proportional hazards regression model to identify prognostic factors. CONCLUSION: Late relapse after completion of 5-year adjuvant endocrine therapy was still common, and grade 3 and more than three positive nodes were the risk factors of late recurrence, while grade 3 was the only risk factor of late distant metastasis. These patients might benefit from extended endocrine therapy.