The influence of patient, tumor and treatment factors on the cosmetic results after breast-conserving therapy in the EORTC 'boost vs. no boost' trial

Purpose: To analyze the influence of different patient, tumor, and treatmen t parameters on the cosmetic outcome after breast-conserving therapy at 3-y ear follow-up. A subjective and an objective cosmetic scoring method was us ed and the results of both methods were compared. Patients and methods: In EORTC trial 2881/10882, 5569 early-stage breast ca ncer patients were treated with tumorectomy and axillary dissection. follow ed by tangential fields irradiation of the breast to a dose of 50 Gy in 5 w eeks, at 2 Gy per fraction. A total of 5318 patients, having a microscopica lly complete tumorectomy, were randomized between no further treatment and a boost of 16 Gy to the primary tumor bed. The cosmetic result at 3-year fo llow-up was assessed by a panel for 731 patients, and by digitizer measurem ents, measuring the displacement of the nipple, for 1141 patients. Univaria te and multivariate analyses were used to evaluate the correlation between various patient, tumor, and treatment factors and cosmesis. Results: The factors associated with a worsened cosmesis according to the p anel evaluation were: an inferior tumor location, a large excision volume, the presence of postoperative breast complications, and the radiotherapy bo ost. According to the digitizer measurements, a central/superior tumor loca tion, a large excision volume, an increased pathological tumor size, an inc reased radiation dose inhomogeneity, and an increased bra cup size resulted in an increased asymmetry in nipple position. It appeared that the evaluat ion of the nipple position (whether by panel or by digitizer) is only moder ately representative of the overall cosmetic outcome. Conclusion: To achieve a good cosmesis, it is necessary to excise the tumor with a limited margin, to avoid postoperative complications, to assess the need for a boost in the individual patient, and to give the radiation dose as homogeneously as possible. As far as the method of evaluation is concer ned. the panel evaluation is the most appropriate method for giving an over all impression of the cosmetic result after breast-conserving therapy (BCT) . The use of the digitizer is recommended for comparing the cosmetic outcom e of two different approaches to BCT or for analyzing cosmetic changes over time. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.