RADT-22. RISING UTILIZATION AND REDUCED MEDICARE SPENDING OF SHORT-COURSE RADIATION THERAPY FOR PRIMARY CNS TUMORS IN ELDERLY ADULTS

Abstract INTRODUCTION For elderly/frail glioma patients, shortening radiotherapy from 6 to 3 weeks (short-course RT [SC-RT]) is non-inferior standard long course (LC-RT) though usage estimated be < 20%. We analyzed real-world utilization of SC-RT with/without systemic therapy in Medicare beneficiaries treated with for primary CNS tumors using CMS data on radiation episodes. METHODS Radiation modality, year, age (65-74, 75-84, ≥ 85), and site-of-care (freestanding vs hospital-affiliated) were evaluated. Utilization (11-20 fractions) LC-RT (21-30 was evaluated by multivariable logistic regression. spending over the 90-day episode linear regression (adjusted β coefficients reported). RESULTS From 2015-2019, 9,572 episodes included (2,966 [31%] SC-RT). increased (27% 2015, 34% 2019; OR 1.2 per year [95%CI:1.1-1.2]) associated older (age 85 65-74, 7.0 [95%CI:5.7-8.7], hospital-affiliated sites (OR [95%CI:1.1-1.4]), conventional (vs IMRT 2.8 [95%CI 2.4-3.3]), lack [95%CI:1.1-1.3]; p 0.001 all). Rise concentrated (interaction = 0.005). Most (6,629, 69%) received no differences (p 0.34). Systemic time (67% 71% 1.1 [95%CI:1.1-1.1]) less likely RT, (p-value significantly reduced (β=$8,416, 95%CI:8,317-8,515), while modestly (β=$316, 95%CI:220-409). CONCLUSIONS While most brain tumors, centers; despite high-level evidence, discrepancy implementation persists necessitates further investigation. Given length had a greater impact than therapy, use appropriate populations reflects an opportunity increase high value care.