CWI Does Not Improve 10-Year OS for Patients With Intermediate-Risk BC Treated With Mastectomy, Systemic Therapy

Background: Despite options, one-third of women with Stage I and II breast cancer (BC) choose mastectomy. Stage II includes T1N1M0, T2N0-1M0, and T3N0M0. Nodal involvement cannot be >1 to 3+ nodes and primary tumor size is ≤5 cm. The Danish and Canadian trials published more than 25 years ago found that postmastectomy radiation reduced local recurrence and improved survival for patients with nodal disease. But the systemic therapy of those patients is now antiquated. Objective: To ascertain the role of chest-wall irradiation (CWI) in patients with BC and +1 to 3 nodes. Design: Randomized, phase III EORTC trial. Participants: Eligible patients had pT1-2N1 M0 or pT2N0M0 disease, which was either grade 3 or had lymphovascular invasion. Methods: Patients were randomized 1:1 to undergo CWI or not to. Stratification was by treatment center. Acceptable doses were 40 Gy/15 fractions to 50 Gy in 25 fractions. Axillary XRT was not allowed but supraclavicular and/or internal mammary irradiat more...