2959 - Ultra-Hypofractionated Radiotherapy in Breast Cancer Before and After COVID-19
Presenter(s)
A. A. Konski1,2, Y. Chung3, C. M. Liu3, E. Rula3, and G. M. Freedman2; 1Leonard Davis Institute of Health Economics University of Pennsylvania, Philadelphia, PA, 2Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 3Neiman Health Policy Institute, Reston, VA
Purpose/Objective(s): Phase III evidence from the United Kingdom has shown non-inferiority of a 5-fraction 1-week ultra-hypofractionation (UH) schedule for postlumpectomy radiotherapy (RT) compared to longer schedules. We assessed whether the COVID-19 pandemic was associated with increased adoption of UH for RT in the United States.
Materials/Methods: This retrospective cohort study used 5% Medicare sample medical claims from 2017 to 2021 and included all beneficiaries with newly diagnosed breast cancer between 2018 and 2021 who underwent breast-conserving surgery and RT, and with 12 months continuous enrollment. Two cohorts were defined by diagnosis date: before (pre-COVID group) and after March 2020 (post-COVID group). Using multivariate regression, RT fractionation schedules were compared between the pre- and post-COVID groups, adjusting for patient characteristics (age, race/ethnicity, region, number of chronic conditions, and dual eligibility). The RT was sorted into four categories: UH (= 5 fractions), hypofractionated (6-10 fractions), moderate (11-21 fractions), and conventional (22+ fractions). Secondary outcomes included duration and cost of RT.
Results: Among 4,086 patients, 2,504 (61%) were in the pre-COVID group and 1,582 (39%) were in the post-COVID group. Both groups were similar in age, health status, and geographical location, but post-COVID patients were more likely to be white (87.4% vs 84.6%, p < 0.05) and less likely to be dual-eligible (6.2% vs 9.6%, p < 0.001). The distribution of RT fractionation differed between pre- and post-COVID groups (Table). The percentage of patients who received UH was 1.7% in the pre-COVID group and 8.4% in the post-COVID group (adj diff = 6.8 pp, p < 0.0001). Conversely, 23.2% of the pre-COVID group underwent conventional RT versus 16.4% of the post-COVID group (adj diff = 6.8 pp, p<0.0001). The post-COVID group, on average, received 1.9 fewer fractions (ß = -1.94; 95% CI, -2.34 to -1.53) with costs that were $412 lower (ß = -412.2; 95% CI, -596.48 to -227.83) than the pre-COVID group.
Conclusion:
A significant shift was observed associated with the COVID-19 pandemic for postlumpectomy RT to 5 fraction UH, and away from conventional RT, resulting in a significant cost saving to Medicare. Abstract 2959 - Table 1: Differences in RT treatment Schedules, Pre- and Post-COVID Cohorts *Adjusted by patient age, race, number of chronic conditions, region, and dual-eligibility status| RT Fraction Category | Pre-COVID, N (%) N = 2504 | Post-COVID, N (%) N = 1582 | Adjusted Difference*, Percentage Points (CI) | P Value |
| Ultra-hypofractionated (= 5 fractions) | 42 (1.68%) | 133 (8.41%) | 6.75 (5.31, 8.20) | < 0.0001 |
| Hypofractionated (6 to 10 fractions) | 70 (2.80%) | 42 (2.65%) | -0.10 (-1.12, 0.91) | 0.8411 |
| Moderate (11-21 fractions) | 1,810 (72.28%) | 1,147 (72.50%) | -0.17 (-2.97, 2.64) | 0.9081 |
| Conventional (= 22 fractions) | 582 (23.24%) | 260 (16.43%) | -6.48 (-8.94, -4.03) | <0.0001 |