Hypofractionated whole-breast radiation therapy (RT) has proved to be equivalent to conventionally fractionated RT in multiple randomized trials. There is controversy regarding its use in younger women because of their underrepresentation in trials and the concern for late toxicity. We evaluated disease control and cosmetic outcomes in patients aged <50 years treated with hypofractionated RT in 4 prospective single-institutional trials.

From 2003 to 2015, 1313 patients were enrolled in 4 prospective protocols investigating the use of adjuvant hypofractionated RT after breast-conserving surgery with a daily or weekly concomitant boost. We identified the records of 348 patients aged <50 years at consultation for this analysis. Overall survival, disease-free survival, and local recurrence-free survival were estimated using the Kaplan-Meier method by study and across studies using meta-analytic methods. The late effects of RT, clinician-rated cosmesis, and patient-rated cosmesis were also evaluated.

With a median follow-up period of 66.9 months, the overall survival rate was 99.6%, the disease-free survival rate was 96.3%, and the local recurrence-free survival rate was 97.7% at 3 years. Clinician-rated cosmesis (n = 242) was excellent or good in 93.4% of cases and fair or poor in 6.6%. Patient-rated cosmesis (n = 259) was excellent or good in 86.1% and fair or poor in 13.9%. When patients rated themselves differently than their physicians, patients more often rated themselves poorly compared with their physicians (P = .0044, Cochran-Mantel-Haenszel test).

At a median follow-up of 5 years, an analysis of patients aged <50 years demonstrated that hypofractionated RT was safe and effective, with good to excellent cosmesis as assessed by both clinicians and patients.