Ultra-Hypofractionated Radiotherapy in Breast Cancer Before and After COVID-19.

OBJECTIVES: We assess whether the COVID-19 pandemic was associated with increased adoption of ultra-hypofractionated (UH) radiotherapy (RT) in the United States. METHODS: A retrospective cohort study of women with early-stage breast cancer across the United States using medical claims of a 5% sample of Fee-for-Service Medicare beneficiaries with newly diagnosed breast cancer treated with lumpectomy and post-surgery radiotherapy between 2018 and 2021. The primary endpoint was the beneficiary's fractionation schedule for the first course of radiotherapy treatment. The schedule was classified as: UH (≤5 fractions), hypofractionated (6 to 10 fractions), moderate (11 to 21 fractions), and conventional (22+ fractions). RESULTS: Among 4086 patients, 2504 (61%) were in the pre-COVID group, and 1582 (39%) were in the post-COVID group. Both groups were similar in age, health status, and geographical location. The UH rate increased 5-fold from 1.7% in the pre-COVID group to 8.4% in the post-COVID group (adj diff=6.8 pp, P<0.0001). Conversely, the conventional RT rate dropped from 23.2% of the pre-COVID to 16.4% of the post-COVID group (adj diff=6.8 pp, P<0.0001). CONCLUSIONS: A significant increase in 5-fraction UH and a decrease in conventional RT treatment were observed among Medicare breast cancer patients in the 18 months following the COVID-19 pandemic.