In all three categories of HSAs, the probability of IMRT use increased over time (p<0.01 for trend). However, compared to low managed care markets, the use of IMRT was constrained in markets with the highest managed care penetration (p<0.01). Markets with high and intermediate managed care penetration shared similar probabilities of IMRT utilization (p=0.67).
HSA, health service area; IMRT, intensity-modulated radiotherapy
*Adjusted for patient-level (i.e., age, tumor grade and stage, and comorbidity) and market-level characteristics (i.e., racial composition, population density, education, income, percent speaking English as a secondary language, number of hospital beds and radiation oncologists in a market, and SEER region).