Impact of the COVID-19 pandemic on early-stage breast cancer post-lumpectomy breast radiation therapy completion.

Abstract

e12682 Background: Whole-breast radiation therapy (RT) following lumpectomy has become a standard of care for early-stage breast cancer (ESBC) treatment. Previous research has demonstrated superior compliance with hypofractionation (HFRT) versus standard fractionation (SFRT). However, the impact of the COVID-19 pandemic on RT completion rates in ESBC has not been well-characterized. Methods: Using the National Cancer Database, patients with ESBC who underwent post-lumpectomy RT from 2018 to 2022 were identified. SFRT was defined as 1.8-2.0 Gray (Gy) per fraction and HFRT as 2.66-2.70 Gy per fraction. RT completion was defined as receipt of ≥46 Gy for SFRT and ≥40 Gy for HFRT. Pre-COVID (2018-2019) and post-COVID (2021-2022) RT completion rates were compared using chi-square tests. Results: Among 25,658 patients, (pre-COVID n=13,381; post-COVID n=12,277), HFRT use increased from 82.9% to 93.6% (p< 0.0001), while SFRT declined (17.1% to 6.4%, p< 0.001). Overall RT completion improved from 94.8% to 96.4% (p< 0.0001). HFRT completion rates remained stable and were higher than SFRT (pre-COVID: 97.2% vs. 83.1%, post-COVID: 97.5% vs. 80.5%, p< 0.0001). HFRT adoption rose across all racial and income groups (p< 0.0001), with completion exceeding 96% across all subgroups. Racial differences in HFRT use decreased from 16.3 to 7.6 percentage points, while income-related differences decreased from 7.4 to 4.4 percentage points. Conclusions: Post-COVID, HFRT adoption after lumpectomy increased while SFRT use decreased by 62.6% of pre-COVID levels. These shifts were accompanied by completion rates exceeding 96% across all groups. A 53.3% and 40.5% relative reduction in racial- and income-related disparities in use were observed, suggesting more equitable treatment delivery. HFRT adoption pre- and post-COVID by race. SFRT HFRT Race Count % Count % p White 2018-2019 (Pre-COVID) 1865 16.32 9565 83.68 <.0001 2021-2022 (Post-COVID) 619 6.02 9669 93.98 African American 2018-2019 (Pre-COVID) 330 26.59 911 73.41 <.0001 2021-2022 (Post-COVID) 133 11.45 1029 88.55 Asian or Pacific Islander 2018-2019 (Pre-COVID) 45 10.34 390 89.66 <.0001 2021-2022 (Post-COVID) 19 3.81 480 96.19 Other or Unknown 2018-2019 (Pre-COVID) 52 18.91 223 81.09 <.0001 2021-2022 (Post-COVID) 18 5.49 310 94.51