Purpose: Delays in initiation of radiotherapy may contribute to inferior oncologic outcomes that are more commonly observed in minoritized populations in the United States. We aimed to examine inequities associated with delayed initiation of intensity-modulated radiotherapy (IMRT).
Materials and methods: The National Cancer Database was queried to identify the 10 cancer sites most commonly treated with IMRT. Interval to initiation of treatment (IIT) was broken into quartiles for each disease site, with the 4th quartile classified as delayed. Multivariable logistic regression for delayed IIT was performed for each disease site using clinical and demographic covariates. Differences in magnitude of delay between subsets of patients stratified by race and insurance status were evaluated using two-sample t-tests.
Results: Among patients (n = 350,425) treated with IMRT between 2004 and 2017, non-Hispanic Black (NHB), Hispanic, and Asian patients were significantly more likely to have delayed IIT with IMRT for nearly all disease sites compared with non-Hispanic White (NHW) patients. NHB, Hispanic, and Asian patients had significantly longer median IIT than NHW patients (NHB 87 days, P < .01; Hispanic 76 days, P < .01; Asian 74 days, P < .01; and NHW 67 days). NHW, Hispanic, and Asian patients with private insurance had shorter median IIT than those with Medicare (P < .01); however, NHB patients with private insurance had longer IIT than those with Medicare (P < .01).
Conclusion: Delays in initiation of IMRT in NHB, Hispanic, and Asian patients may contribute to the known differences in cancer outcomes and warrant further investigation, particularly to further clarify the role of different insurance policies in delays in advanced modality radiotherapy.