Possible benefits from post-mastectomy radiotherapy in node-negative breast cancer patients: a multicenter analysis in Korea (KROG 14-22)

Abstract

PurposeThis study was performed to identify a subset of patients who may benefit from post-mastectomy radiotherapy (PMRT) among node-negative breast cancer patients.Materials and MethodsWe retrospectively reviewed 1,828 patients with pT1-2N0 breast cancer, treated with mastectomy without PMRT from 2005 to 2010 at 10 institutions. Univariate and multivariate analyses for locoregional recurrence (LRR) and any first recurrence (AFR) were performed according to clinicopathologic factors and biologic subtypes.ResultsDuring a median follow-up period of 5.9 years (range: 0.7-10.4 years), 98 patients developed AFR (39 isolated LRR, 13 LRR with synchronous distant metastasis, and 46 isolated distant metastasis), and 52 patients developed LRR. The 7-year LRR and AFR rates were 3.8% and 6.7%, respectively. Multivariate analysis revealed that age of ≤ 40 years (p<0.001) and T2 stage (p=0.013) were independent risk factors for LRR. The 7-year LRR rates were 2.5% with no risk factors, 4.5% with one risk factor, and 12.4% with two risk factors. Multivariate analysis for AFR revealed that age of ≤ 40 years (p<0.001), T2 stage (p<0.001), and triple-negative biological subtype (p=0.045) were independent risk factors for AFR. The 7-year AFR rates were 3.9% with no risk factors, 8.4% with one risk factor, and 15.7% with two to three risk factors.ConclusionsMastectomy without PMRT is a sufficient local treatment for pT1-2N0M0 breast cancer. Nevertheless, PMRT might be considered for patients with two or three risk factors, among those of young age, with T2 tumors, and with the triple-negative biological subtype based on LRR and AFR.

Evaluation of the benefit of post‑mastectomy radiotherapy in patients with early‑stage breast cancer: A propensity score matching study

“…Other research demonstrated that post-MAS radiotherapy (PMRT) has a strong potential to produce a positive prognosis in females with stage T3-T4 breast cancer, or those where the cancer has spread to four or more positive axillary lymph nodes (LNs) (10,11). Furthermore, a large retrospective study indicated that patients with node-negative breast cancer may also benefit from PMRT (12). However, the use of PMRT to improve breast cancer-specific survival (BCSS) and OS rates in early-stage (T1-2) breast cancer, and those with one to three positive axillary LNs, is controversial (13), due to limited clarity in the current evidence and a lack of data from large, high-quality clinical studies.…”