Late Toxicities and Quality of Life After a Radiation Boost for Breast Ductal Carcinoma In Situ: Boost or No Boost in DCIS Randomized Trial.

Abstract

In ductal carcinoma in situ, whole breast radiation therapy (WBRT) reduces local recurrence rates, but ipsilateral breast events at 10 years were observed in 15% to 19% of 50-year-old patients. The BONBIS trial (NCT00907868) assessed the effect of an additional localized radiation boost on local recurrence-free survival (primary endpoint). This large multicenter (n = 53), randomized, open-label phase 3 trial was conducted from November 2008 to July 2014. In total, 2004 patients with complete ductal carcinoma in situ resection underwent postsurgery WBRT followed or not by a 16-Gy boost in the tumor bed. Only late radiation therapy-induced toxicity occurrence (National Cancer Institute Common Terminology Criteria for Adverse Events v3.0), health-related quality of life European Organisation for Research and Treatment Of Cancer (EORTC) Quality of life Cancer Patients (QLQ-C30) v3.0 and EORTC Quality of life Breast Cancer Patients (QLQ-BR23), and potential predictive factors of breast subcutaneous fibrosis (BSCF) (ie, secondary endpoints) will be reported here because the primary endpoint has not been reached yet. After a median follow-up of 66.9 months (95% CI, 65.1-67.8), grade ≥2 BSCF was observed in 4.9% of patients (7.0% in the WBRT + boost vs 2.8% in the WBRT arm; P < .001). Grade ≥2 acute and late toxicities were positively correlated (P = .005). Grade ≥2 BSCF was correlated with the boost (odds ratio = 2.6; 95% CI, 1.62-4.30) and breast clinical target volume ≥500 cm³ (odds ratio = 1.6; 95% CI, 1.01-2.51). Among the QLQ-C30 and QLQ-BR23 domain and symptom scores, only the breast symptom scores exhibited an arm-by-time interaction effect (P = .001) with a greater long-term breast symptom experience in the WBRT + boost arm. Time to first deterioration analysis showed a statically significant deterioration for body image in the WBRT + boost arm (hazard ratio = 1.19; 95% CI, 1.00-1.41). The boost significantly increased grade ≥2 BSCF occurrence and persistent breast symptoms.