Outcomes with and without postmastectomy radiotherapy for pT3N0-1M0 breast cancer: An institutional experience

Aim: The objective of this study is to comprehensively evaluate the therapeutic efficacy of postmastectomy radiotherapy (PMRT) in treating patients with pT3N0-1M0 breast cancer within the context of modern therapeutic strategies.Methods: Clinical data from patients with pT3N0-1M0 breast cancer who underwent mastectomy from January 2005 to December 2018 at our institution were retrospectively analyzed.Results: The study involved a total of 222 participants, with 112 individuals undergoing PMRT and 110 individuals not receiving it. The median follow-up duration was 77 months (range: 6-171 months). The entire cohort demonstrated 5-year disease-free survival (DFS) and overall survival (OS) rates of 85.1% and 91.0%, respectively, along with a locoregional recurrence (LRR) rate as low as 7.2%. The PMRT group showed significantly better 5-year DFS (90.2% vs. 80.0%, p = 0.02) and OS (95.5% vs. 86.4%, p = 0.012) rates, as well as a lower LRR rate (4.5% vs. 10.0%, p = 0.122), compared to the group without PMRT. Cox regression analysis confirmed the independent prognostic significance of PMRT for both DFS (p = 0.040) and OS (p = 0.047). Following propensity score matching (PSM), the analysis included 100 matched patients, revealing an improved prognosis for those who received PMRT (DFS: p = 0.067; OS: p = 0.043).Conclusions: Our study reveals favorable prognoses for pT3N0-1M0 breast cancer patients treated within contemporary therapeutic approaches. The pivotal role of PMRT in this context is evident. However, due to the retrospective design of our study and the relatively limited sample size, further investigation is imperative to validate and enhance these initial findings.