Radiotherapy Strategies for Stage II Breast Cancer With Lymphovascular Invasion After Mastectomy

Background/Aim: Lymphovascular invasion (LVI) is a strong prognostic factor associated with poor survival outcomes in breast cancer. However, the clinical benefit of postmastectomy radiotherapy (PMRT) for early-stage disease remains uncertain. This study aimed to evaluate PMRT efficacy and related prognostic factors in real-world settings. Patients and Methods: We retrospectively analyzed 322 postoperative breast cancer patients with pathologically confirmed LVI who received radiotherapy (RT) between October 2017 and July 2020. Patients were categorized into two groups: Group A (pT1–2N1M0, n=273), who underwent modified radical mastectomy (MRM) with or without adjuvant RT; and Group B [stage II, ypN0 after neoadjuvant chemotherapy (NAC) and surgery, with or without adjuvant RT, n=49]. Intergroup differences were assessed using the chi-squared test, and Kaplan–Meier analysis estimated local recurrence-free survival (LRFS), disease-free survival (DFS), overall survival (OS), and distant DFS (DDFS). Results: Group A: Patients who received adjuvant RT had significantly improved 5-year LRFS (94.4% vs. 85.5%, HR=0.359, 95% CI=0.147–0.879; p