Reduction in Doses to Organs at Risk and Normal Tissue During Breast Radiation Therapy With a Carbon-Fiber Adjustable Reusable Accessory.

Purpose: This pilot study (ClinicalTrials.gov NCT04543851) investigates a novel breast positioning device using a low density, high tensile carbon-fiber cradle to support the breast, remove the inframammary fold, and reduce dose to organs at risk for whole breast radiation therapy in the supine position.

Methods And Materials: Thirty patients with inframammary folds ≥1 cm or lateral ptosis in supine treatment position were planned with standard positioning and with a carbon-fiber Adjustable Reusable Accessory (CARA) breast support. Twenty patients received whole breast with or without 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.

Results: CARA removed all inframammary folds and reduced V20Gy V105%, and V50% , without compromising target coverage. Median (range) V20Gy for whole breast radiation therapy was 12.3% (1.4%-28.7%) with standard of care versus 10.9% (1.2%-17.3%) with CARA (Wilcoxon P = .005). Median V105% was 8.0% (0.0%-29%) with standard of care versus 4.0% (0.0%-23%) with CARA (P = .006) and median V50% was 3056 mL (1476-5285 mL) versus 2780 mL (1415-5123 mL) with CARA (P = .001). CARA was compatible with deep inspiration breath hold and achieved median V25Gy = 0.1% (range 0%-1.9%) for all patients with left breast cancer. Skin reactions with CARA were consistent with historical data and daily variation in treatment setup was consistent with standard supine positioning.

Conclusions: CARA can reduce V105%, lung and normal tissue dose, and remove the inframammary fold for breast patients with large or pendulous breasts and high body mass index treated in the supine position, without compromising target coverage. CARA will undergo further study in a randomized controlled trial.