Adequate locoregional treatment for early breast cancer may prevent secondary dissemination.

Abstract

PURPOSETo analyze different events that determine event-free survival (EFS) in a randomized trial on adjuvant radiotherapy in early breast cancer patients with more than 15 years of follow-up evaluation.PATIENTS AND METHODSThe trial included 960 patients with a unilateral, operable breast cancer. Surgery consisted of a modified radical mastectomy. The trial compared three arms, as follows: preoperative radiotherapy, postoperative radiotherapy, and no adjuvant treatment. Events were analyzed by a competing-risk approach. A proportional hazards multiple regression model was used to analyze the effects of radiotherapy on the risk of distant metastasis. Similar analyses were performed separately for node-negative [N(-)] and node-positive [N(+)] patients in the two groups that did not include preoperative radiotherapy.RESULTSRadiotherapy produced a fivefold decrease of the risk of local recurrence (P < .0001). In N(+) patients, postoperative radiotherapy decreased the risk of distant dissemination (relative ri...