Predictors for poor cosmetic outcome in patients with early stage breast cancer treated with breast conserving therapy: Results of the Young boost trial

Abstract

Purpose: In the Young Boost trial (YBT), breast cancer patients ≤50 years of age, treated with breast conserving therapy (BCT) were randomized between a 26 Gy boost dose and a 16 Gy boost dose, with local recurrence as primary and cosmetic outcome (CO) as secondary endpoint. Data of the YBT was used to investigate which factors are related with worse cosmetic outcome after BCT.

Methods: From 2004 to 2011, 2421 cT1-2N0-2a breast cancer patients were randomized. CO was scored subjectively by the patient and physician, and objectively using BCCT.core: at baseline, one and four years after treatment. Associations between potential risk factors for worse cosmetic outcome, based on the objective BCCT.core, were investigated using a proportional odds model.

Results: At four years, CO was significantly better in the standard boost group for all three scoring methods (satisfied CO ±65% vs 55%). A photon boost, high boost dose, poor cosmesis before radiation therapy, large boost volume and adjuvant chemotherapy significantly deteriorated CO.

Conclusion: Important risk factors for worse CO were the use of a photon boost instead of an electron boost, a high boost dose, cosmesis at baseline, adjuvant chemotherapy and boost volume. These results can be used to define strategies aimed at improving CO.

Keywords: Breast conserving therapy; Cosmetic outcome; Fibrosis; Young boost trial; Young patients.