152 - National Expansion and Radiation Oncology Participation in Radiopharmaceutical Therapy: Medicare Provider Trends 2013-2023

Purpose/Objective(s): Radiopharmaceutical therapy (RPT) use has expanded rapidly, but specialty participation and treatment intensity patterns remain incompletely characterized. We evaluated national Medicare Provider Utilization and Payment Data (2013–2023) to quantify population-normalized growth, specialty share trends, and radiation oncology (RO) participation relative to external beam radiation therapy volume.

Materials/Methods: Medicare Physician & Other Practitioners PUF files (2013–2023) were analyzed. Intravenous RPT administrations (CPT 79101) were aggregated by year and specialty and grouped as RO, Nuclear Medicine (NM), Diagnostic/Interventional Radiology (DR/IR), Medical Oncology/Hematology, or Other. Utilization was normalized to Medicare Fee-for-Service (FFS) Part B enrollment (services per 100,000 beneficiaries). Specialty share trends were modeled using Poisson regression with log(total 79101) offsets and robust variance. RO administration intensity was modeled using log(77427) offsets. Sensitivity analyses incorporated CPT 77435 (SBRT course management) in denominators and CPT 77750 (infusion of radioelement solution) in numerators.

Results: National 79101 services increased from 529 (2013) to 12,395 (2023). Administration rates increased from 1.60 to 43.30 per 100,000 Medicare Part B FFS beneficiaries. Absolute 79101 volume increased across all specialty groups over the study period. DR/IR share (IRR 1.09, 95% CI 1.07–1.12) and med onc/heme share (IRR 1.65, 95% CI 1.37-1.97) increased annually, while NM share (IRR 0.97, 95% CI 0.95–0.99) and RO share (IRR 0.91, 95% CI 0.88–0.95) declined modestly. Despite proportional shifts, RO administration intensity increased from 0.11 to 2.25 administrations per 1,000 77427 services (IRR 1.15 per year, 95% CI 1.14–1.16). Results were robust when incorporating 77435 in denominators (IRR 1.15) and when including 77750 in the numerator (IRR 1.13).

Conclusion: RPT utilization in traditional Medicare increased more than twenty-fold nationally and more than twenty-five-fold after normalization to FFS enrollment from 2013–2023. Although proportional specialty participation shifted toward DR/IR, absolute volume and EBRT-adjusted RPT volume within RO increased significantly over time. These findings clarify workforce participation dynamics during national RPT expansion and provide context for future policy and training discussions.