Reduction in doses to organs at risk and normal tissue during breast radiotherapy with a Carbon-fibre Adjustable Reusable Accessory (CARA).

Abstract

BACKGROUND AND PURPOSE\nThis pilot study (Clinical trials.gov xxxxxx) investigates a novel breast positioning device using a low density, high tensile carbon-fibre cradle to support the breast, remove the infra-mammary fold and reduce dose to organs at risk for whole breast radiotherapy in the supine position.\n\n\nMATERIALS AND METHODS\nThirty patients with infra-mammary folds ≥ 1 cm and/or lateral ptosis in supine treatment position were planned with standard positioning and with a Carbon-fibre Adjustable Reusable Accessory (CARA) breast support. 20 patients received whole breast +/- regional nodal irradiation with 42.5 Gy in 16 fractions or 50 Gy in 25 fractions using CARA. Median body mass index was 32 in this study.\n\n\nRESULTS\nCARA removed all infra-mammary folds and reduced V20Gyipsilateral lung, V105%breast, and V50% body, without compromising target coverage. Median (range) V20Gyipsilateral lung for whole breast radiotherapy was 12.3% (1.4% - 28.7%) with standard of care versus 10.9% (1.2% - 17.3%) with CARA, Wilcoxon p\u202f=\u202f0.005. Median V105% breast was 8.0% (0.0% - 29%) with standard of care versus 4.0% (0.0% - 23%) with CARA, (p\u202f=\u202f0.006) and median V50% body was 3056 cc (1476 cc - 5285 cc) versus 2780 cc (1415 cc - 5123 cc) with CARA, p\u202f=\u202f0.001. CARA was compatible with deep inspiration breath hold (DIBH) and achieved median V25Gyheart =0.1% (range 0% -1.9%) for all left breast patients. Skin reactions with CARA were consistent with historical data and daily variation in treatment setup was consistent with standard supine positioning.\n\n\nCONCLUSIONS\nCARA can reduce V105%breast, lung and normal tissue dose, and remove the infra-mammary fold for breast patients with large or pendulous breasts and high BMI treated in the supine position, without compromising target coverage. CARA will undergo further study in a randomized controlled trial.