Locoregional failure in early-stage breast cancer patients treated with radical mastectomy and adjuvant systemic therapy: which patients benefit from postmastectomy irradiation?

Abstract

To assess the locoregional failure in patients with Stage I-II breast cancer treated with radical mastectomy and to evaluate whether a subset of these patients might be at sufficiently high risk of locoregional recurrence (LRR) to benefit from postmastectomy irradiation (PMRT). Stage I-II breast cancer patients (n = 150) treated with radical mastectomy without adjuvant irradiation between 1999 and 2005 were analyzed. The pattern of LRR was reported. Kaplan-Meier analysis was used to calculate rates of LRR, and Cox proportional hazards methods were used to evaluate potential risk factors. Median follow-up was 75 months. Mean patient age was 56 years. One-hundred forty-three (95%) patients received adjuvant systemic therapy: 85 (57%) hormonal therapy alone, 14 (9%) chemotherapy alone, and 44 (29%) both chemotherapy and hormonal therapy. Statistically significant factors associated with increased risk of LRR were premenopausal status (p = 0.004), estrogen receptor negative cancer (p = 0.02), pathologic grade 3 (p = 0.02), and lymphovascular invasion (p = 0.001). T and N stage were not associated with increased risk of regional recurrence. The 5-year LRR rate for patients with zero or one, two, three, and four risk factors was 1%, 10.3%, 24.2%, and 75%, respectively. A subset of patients with early-stage breast cancer is at high risk of LRR, and therefore PMRT might be beneficial.