Prognostic factors for breast cancer patients with T1-2 tumor and 1-3 positive axillary nodes treated using total mastectomy without radiotherapy.

Prospective randomized trials have demonstrated that postmastectomy radiotherapy (PMRT) improves not only locoregional recurrence-free survival, but also overall survival for node-positive breast cancer patients. Subset analyses in previous trials have shown that improvement of overall survival with PMRT is not always demonstrated for patients with 1-3 positive nodes. Indications for PMRT are still marginal for patients with pathological invasion 5 cm in diameter and 1-3 positive nodes. The aim of this study was to clarify poor prognostic factors for breast cancer patients with pathological invasion size 5 cm and 1-3 positive nodes. Participants comprised 428 breast cancer patients with T1-2 tumor and 1-3 positive axillary nodes (pT1-2 N1) treated using total mastectomy without radiotherapy. Correlations between clinicopathological characteristics and 10-year Kaplan-Meier estimates of locoregional recurrence-free survival, disease-free survival, and overall survival were retrospectively analyzed. Median follow-up was 98 months. Locoregional recurrence was observed in 20 patients (4.7%), and distant recurrence was observed in 70 patients (16.4%). Disease-free survival rate was 80.8%, and overall survival rate within the study period was 90%. Multivariate analysis demonstrated that favorable prognostic factors for locoregional recurrence-free survival were the presence of chemotherapy and positive hormone receptor status, and for disease-free survival were presence of chemotherapy, pT1 tumor, and single positive node. Physicians may consider these favorable prognostic factors in decision to eliminate PMRT from patients with the borderline indications.