Trends in radiation therapy and other procedural treatments for keratinocyte carcinomas among dermatologists: A cohort study

Summary: Background: Prior findings from aggregated national Medicare claims data indicate that dermatologist use of radiation therapy (RT) has increased over time, but RT has not been investigated at an individual tumor level. Our objective was to report the proportion of procedures used to treat keratinocyte carcinomas (KC), including RT, among general dermatologists and Mohs surgeons, and assess trends over time within a Medicare cohort. Methods: We conducted a retrospective cohort study using a de-identified random sample of 5,560,291 Medicare beneficiaries from 2009-2021. We included all KCs procedurally treated by dermatologists, defined by at least 1 CPT code for KC treatment (ED&C, excision, Mohs surgery, photodynamic therapy (PDT), or RT) and at least 1 ICD code for a KC diagnosis on the same date. We assessed trends over time of the proportions of KCs treated by each procedure type with Kendall Tau-b tests. Results: We identified 818,685 patients with 2,684,775 procedurally treated KCs (42.9% by general dermatologists and 57.1% by Mohs surgeons). There were 10,906 KCs treated with RT (0.004%; with 45% basal cell carcinoma, 47.2% squamous cell carcinoma, 7.8% unspecified in a 2011-2021 subset). Most RT overall was performed by Mohs surgeons (58.7%); Mohs surgeons used RT on a 0.42% of treated KCs, general dermatologists used RT on 0.39% of treated KCs. The proportion of KCs treated with RT increased over time, as did the proportion treated with Mohs surgery, while the proportion of KCs treated with ED&C decreased over time (all p for trend <.05). Conclusions: Our findings indicate that although RT makes up a small proportion of KC treatments, the proportion is increasing over time. Olivia G. Cohen¹, Gabriella V. Alvarez², Kai-Ping Liao², Kevin Nead³, Mackenzie Wehner² 1. Dermatology, University of Virginia, Charlottesville, VA, United States. 2. Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, TX, United States. 3. Epidemiology, The University of Texas MD Anderson Cancer Center Division of Radiation Oncology, Houston, TX, United States. Clinical Research: Epidemiology and Observational Research