Multinational phase 3 trial postmastectomy chest-wall irradiation in breast cancer: ten-year survival outcomes

The multinational phase 3 SUPREMO trial evalutated the omission of postmastectomy chest-wall irradiation in women with intermediate-risk breast cancer (stage pT1N1, pT2N1, or pT3N0 or pT3N0 with a histologic grade of 3, lymphovascular invasion, or both) undergoing contemporary adjuvant systemic therapy. Patients were assigned to undergo chest-wall irradiation (40 to 50 Gy; n=808) or no chest-wall irradiation (n=799). The primary endpoint was overall survival. The median follow-up was 9.6 years. Ten-year overall survival rate was 81.4% with chest-wall irradiation and 81.9% with no chest-wall irradiation. Recurrence was observed in 1.1% of patients in the irradiation group and 2.5% of patients in the no-irradiation group . Disease-free survival rate was 76.2% in the irradiation group and 75.5% in the no-irradiation group, and distant metastasis-free survival rate was 78.2% and 79.2%, respectively.The authors conclude that postmastectomy chest-wall irradiation did not improve overall survival among patients with intermediate-risk, early breast cancer (quick take video summary).