04 National Adoption of Ultra-Hypofractionated (5-Fraction) External Beam Radiation Therapy in the United States, 2020–2023: An NCDB Analysis

Background

Ultra-hypofractionated radiation therapy (RT), including 5-fraction regimens, has expanded across multiple disease sites, offering greater convenience and potentially lower resource utilization. Real-world national adoption among patients receiving radiation therapy remains incompletely characterized.

Materials and Methods

We conducted a retrospective cohort study using the National Cancer Database (NCDB) Participant Use File. Diagnosis years 2020 to 2023 were evaluated. Radiation fraction count was derived from the NCDB phase 1 number of fractions variable and converted to a numeric comparator. A binary outcome was created to identify 5-fraction courses (y_5fx_rt), defined among patients with RT and non-missing fraction information (RT-known denominator). We quantified year-specific adoption of 5-fraction RT among RT-known patients using cross-tabulations.

Results

Among all cases in the file (n = 4,513,685), 42.7% had RT-known fraction information (n = 1,928,719). Within this RT-known cohort, 67,122 patients received 5 fractions, corresponding to 3.5% of RT-known radiation courses. When restricting to diagnosis years 2020 to 2023 with available RT-known fraction data (valid; n = 536,783), year-specific 5-fraction utilization increased over time: 2020, 4.3% (5312/124,368); 2021, 8.1% (11,501/142,173); 2022, 12.7% (17,727/139,518); and 2023, 17.4% (22,758/130,724) (row percentages within diagnosis year). Across 2020 to 2023, overall 5-fraction utilization in the RT-known cohort was 10.7% (57,298/536,783), demonstrating a consistent upward temporal trend.

Conclusions

In a national NCDB cohort, adoption of 5-fraction external beam RT increased substantially from 2020 through 2023, rising from 4.3% to 17.4% among RT-known courses. These findings suggest rapid diffusion of ultra-hypofractionation in contemporary US practice. Future analyses should evaluate variation by facility characteristics and patient sociodemographic factors and assess whether adoption patterns align with evidence-based indications.