Radiotherapy Can Improve the Disease-Free Survival Rate in Triple-Negative Breast Cancer Patients with T1–T2 Disease and One to Three Positive Lymph Nodes After Mastectomy

Abstract

Abstract Learning Objectives Evaluate the effect of postmastectomy radiotherapy (PMRT) in terms of locoregional recurrence-free survival and disease-free survival in triple-negative breast cancer (TNBC) patients. Identify the subgroup of TNBC patients most likely to benefit from PMRT. Assess the role of PMRT in TNBC patients with intermediate-risk (T1/2N1) disease. Purpose. Several studies have demonstrated poor locoregional control in patients with triple-negative breast cancer (TNBC), compared with other molecular subtypes of breast cancer. We sought to evaluate whether or not postmastectomy radiotherapy (PMRT) improves locoregional recurrence-free survival (LRFS) and disease-free survival (DFS) outcomes in TNBC patients. Methods and Materials. Between January 2000 and July 2007, 553 TNBC patients treated with modified radical mastectomy from a single institution were analyzed retrospectively. Patients were categorized into three groups: low risk (stage T1–T2N0), intermediate risk (stage T1–T2N1), and high risk (stage T3–T4 and/or N2–N3). Cox proportional hazards models were used to evaluate the association between PMRT and LRFS and DFS times after adjusting for other clinicopathologic covariates. Results. With a median follow-up of 65 months (range, 1–140 months), 51 patients (9.2%) developed locoregional recurrence and 135 patients (24.4%) experienced disease recurrence. On multivariate analysis, PMRT was associated with significantly longer LRFS and DFS times in the entire cohort. In the intermediate-risk group, PMRT was associated with a longer DFS time but not with the LRFS interval. In the high-risk group, PMRT was associated with significantly longer LRFS and DFS times. Conclusion. PMRT is associated with longer LRFS and DFS times in high-risk TNBC patients and a longer DFS time in intermediate-risk TNBC patients. Prospective randomized studies are needed to investigate the best locoregional treatment approaches for patients with this molecular subtype of breast cancer.