Locoregional radiation therapy in patients with high-risk breast cancer receiving adjuvant chemotherapy: 20-year results of the British Columbia randomized trial.

Background: The British Columbia randomized radiation trial was designed to determine the survival impact of locoregional radiation therapy in premenopausal patients with lymph node-positive breast cancer treated by modified radical mastectomy and adjuvant chemotherapy. Three hundred eighteen patients were assigned to receive no further therapy or radiation therapy (37.5 Gy in 16 fractions).