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

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.

Factors associated with patient-reported cosmetic outcome in the Young Boost Breast Trial.

PURPOSE: To investigate which factors are related to patient reported cosmetic outcome (PRCO) after breast conserving therapy. METHODS: From 2004 to 2011, 2421 cT1-2N0-2a breast cancer patients were randomised in the Young Boost Trial between a 16 and a 26Gy boost to the tumour bed. Cosmesis was scored subjectively by the patient and physician, and objectively using BCCT.core, at baseline, one and four years after treatment. Presence of fibrosis, QoL and rib pain at four years were also scored. Data were complete for 864 patients. The relation between the separate components was investigated using a proportional odds model. RESULTS: Of the 7 BCCT.core parameters, the distance from nipple to inframammary fold and the length of the breast contour were significantly related to the overall PRCO at four years. Patients with more fibrosis and poorer QoL scored their cosmesis worse, while rib pain was not related. The agreement between the different scores was low (kappa 0.26-0.42). CONCLUSION: The distance from nipple to inframammary fold, the length of the breast contour and the severity of fibrosis were the main factors related to patient-reported cosmetic outcome. Patients with better QoL scored their cosmesis better.

Set-up verification and 2-dimensional electronic portal imaging device dosimetry during breath hold compared with free breathing in breast cancer radiation therapy.

PURPOSE: To compare set-up and 2-dimensional (2D) electronic portal imaging device (EPID) dosimetry data of breast cancer patients treated during voluntary moderately deep inspiration breath hold (vmDIBH) and free breathing (FB). METHODS AND MATERIALS: Set-up data were analyzed for 29 and 51 consecutively treated patients, irradiated during FB and vmDIBH, respectively. Of the 51 vmDIBH patients, the first 25 had undergone an extra trained computed tomography (CT) scan and used an additional "breathing stick" (vmDIBH_trained). The last 26 patients did not use the breathing stick and did not undergo a trained CT (vmDIBH_untrained). The delivered 2D transit dose was measured with EPID in 15 FB and 28 vmDIBH patients and compared with a 2D predicted dose by calculating global gamma values γ using 5% and 5 mm as dose difference and distance-to-agreement criteria, respectively. Measurements with a percentage of pixels with an absolute gamma value > 1 (|γ| > 1) greater than 10% were classified as deviating. RESULTS: Only small, sub-millimeter differences were seen in the set-up data between the different patient groups. The mean of means, systematic error, and random error ranged from - 0.6 mm to 3.3 mm. The percentage of pixels with |γ| > 1 for all patients was 9.8% (2-25.8). No statistically significant differences were observed between the patient groups. In total, 38% of the gamma images were classified as deviating: 43.6% in vmDIBH_untrained patients compared with 38.0% in vmDIBH_trained patients and 33.3% in FB patients (P > .05). CONCLUSION: Both set-up and 2D EPID dosimetry data indicate that reproducibility of radiation therapy for patients treated during FB and vmDIBH is similar. Small but not significant differences in 2D EPID dosimetry were observed. Further investigation with 3-dimensional EPID dosimetry is recommended to investigate the clinical relevance of deviant gamma images.