Background
Ultra-hypofractionated breast radiotherapy (RT) delivered in 5 fractions is supported by randomized trial evidence and is increasingly incorporated into contemporary practice. However, real-world adoption and equity of uptake across the US remain incompletely characterized.
Methods
Using National Cancer Database (NCDB) RT fractionation fields, we identified RT courses with evaluable fraction counts and created a binary indicator for 5-fraction RT (Yes/No). We assessed temporal trends by diagnosis year (2020 to 2023) and examined associations between 5-fraction RT and sociodemographic factors (primary insurance, urban/rural status, neighborhood income quartiles, race) using chi-square testing.
Results
Among RT courses with complete year and 5-fraction indicator available from 2020 to 2023 (n = 536,783), 5-fraction RT increased sharply over time: 4.3% in 2020 (5312/124,368); 8.1% in 2021 (11,501/142,173); 12.7% in 2022 (17,727/139,518); and 17.4% in 2023 (22,758/130,724), for an overall 10.7% increase (57,298/536,783) from 2020 to 2023 (P <.001).
In an “eligible fractionation” analytic subset (5, 15-16, 25-28 fractions; n = 31,448), 5-fraction RT represented 11.7% (3683/31,448) and differed meaningfully by insurance (P <.001): Medicare, 17.4%; Private, 7.6%; Medicaid, 5.9%; Uninsured, 6.9%. Urban/rural residence was also associated with 5-fraction RT use (P <.001), ranging from 7.3% in mid-size metro areas (250,000 to 1 million population) to ~17.7% to 18.1% in more remote/non-adjacent categories; large metro areas (≥1 million) had 12.8% uptake. Neighborhood income showed a modest gradient (P <.001): 10.1% in the lowest quartile (<$38,000) vs 12.5% in the highest (≥$63,000). Race was associated with uptake (P <.001), with lower use among Black vs White patients (9.4% vs 12.2%) and heterogeneity across smaller racial subgroups.
Conclusions
Five-fraction breast RT adoption is accelerating rapidly in the US, particularly after 2021, but uptake is uneven by insurance and geography, with persistent sociodemographic differences. Targeted implementation strategies and reimbursement/operational support may be needed to prevent widening inequities as ultra-hypofractionation becomes standard.
