Racial and Ethnic Health Disparities in Delay to Initiation of Intensity-Modulated Radiotherapy

Abstract

QUESTION ASKED: While controlling for clinical, soci-odemographic, and health systems factors, are there significant differences in timeliness of initiating curative-intent treatment with intensity-modulated radiation therapy (IMRT) among racial and ethnic minorities? SUMMARY ANSWER: Non-Hispanic Black (NHB), Hispanic , and Asian patients were significantly more likely to have delays in initiation of treatment with IMRT for nearly all included disease sites compared with non-Hispanic White (NHW) patients. NHW, Hispanic, and Asian patients with private insurance had shorter intervals to initiation of treatment than those with Medicare; however, NHB patients with private insurance had longer intervals to initiation of treatment than those with Medicare. WHAT WE DID: From the National Cancer Database, we identified 716,082 patients with 10 different primary malignancies commonly treated with IMRT and quantified the interval of time between diagnosis and initiation of radiotherapy. We produced multivariable logistic regression models for each disease site to identify predictors of delay in treatment while controlling for clinical, sociodemographic, and health systems factors. WHAT WE FOUND: We found evidence of racial disparities in timeliness of treatment with IMRT among NHB, Hispanic, and Asian patients compared with NHW patients. In our analysis, the median interval to initiation of treatment with IMRT was 20 days longer for NHB patients, 10 days longer for Hispanic patients, and 7 days longer for Asian patients, compared with NHW patients. Unlike NHW, Hispanic, and Asian patients, NHB patients with private insurance experienced longer delays in treatment than those with Medicare. BIAS, CONFOUNDING FACTORS, REAL-LIFE IMPLICATIONS: Because of the retrospective nature of this large database study, there are measured cofounders, for example specific insurance policies and oncologic outcomes such as local control. This limits direct conclusions regarding the clinical impact of delayed IIT. To our knowledge, this is the largest-scale report of disparities in the timeliness of radiation across multiple disease sites. Further investigation into the causes of these delays is urgently needed to improve timely initiation of IMRT and reduce related health care inequities. abstract 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 4 th 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 5 350,425) 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.