Cost Savings of Three Fraction Accelerated Partial Breast Versus Standard of Care Adjuvant Radiotherapy: Cost Analysis of a Prospective Phase II Study

Abstract

Accelerated partial breast radiotherapy (APBI) is an established option for favorable early stage breast cancer. In the current reimbursement environment, increased emphasis is being placed on high value care, and an alternative payment model has been released which will include episodic payments for breast cancer. This analysis aims to evaluate the potential cost saving of three fraction APBI as given per MC1532 versus standard of care radiotherapy (RT). MC1532 is a prospective phase II study evaluating adjuvant APBI after breast conservation surgery either given with 3 fraction brachytherapy, external beam photon or proton therapy. Eligible patients had Stage 1 invasive breast cancer or DCIS, ER+, with negative margins. Fractionation was 7 Gy x 3 for brachytherapy and 7 Gy (RBE) x 3 for photons and protons administered daily to the post-operative cavity with a 1cm CTV margin. A matched standard of care control group was retrospectively identified treated with predominantly hypofractionated whole breast radiotherapy (WBRT) or twice daily APBI brachytherapy. Standardized cost data was collected from the Mayo Clinic Cost Data Warehouse for the surgical and radiation period and categorized into RT related vs other costs. Mean costs were compared between groups via Mann-Whitney U testing and multivariate linear regression was used to identify associations with higher costs. A total of 115 patients treated with three fraction APBI per MC1532 (38 photons, 34 proton, and 43 brachytherapy) with available cost data and 580 matched patients (490 photons and 90 brachytherapy) treated from 2014-2017 with standard of care were included. Patient and disease characteristics were similar between the MC1532 and standard of care groups; the mean age was 66 vs 63 years. 82% vs 76% had invasive breast cancer. Hormone therapy was administered in 71% and 74%, and chemotherapy was rare <3%. The median number of fractions in the standard of care arm WBRT arm was 19 and brachytherapy arm was 10, versus 3 in MC1532. Mean RT cost for MC1532 was $3,980 versus $5,494 for standard of care, a 28% reduction (p<0.01). When analyzed by modality, patients treated on protocol consistently had lower RT costs: Photon ($4,763 vs $3,283, p<0.01), brachytherapy ($9,471 vs $3,879, p<0.01). Mean proton therapy cost on MC1532 was $4,889. On multivariate analysis not participating in MC1532, brachytherapy, left sided cancer, and younger age were significantly associated with increased costs. Three fraction APBI as tested on MC1532 was associated with 28% lower RT cost versus standard of care adjuvant radiation, which was more pronounced for brachytherapy (57%) than photon RT (34%).Tabled 1Abstract 2882; Table; Mean Radiotherapy CostsMC1532Median FractionsStandard of CareMedian FractionsWBRT$3,2833$4,76319Proton$4,8893----Brachytherapy$3,8793$9,47110 Open table in a new tab