Late-Stage Oral Cancer Detection After California and Illinois Restored Medicaid Dental Benefits.

Abstract

Previous research found an association between California's Medicaid dental coverage and oral cancer detection. However, this relationship has yet to be explored in other states or by subgroup populations. In addition to controlling for sociodemographic and tumor characteristics, this study implemented a traditional difference-in-differences design to compare distant-stage diagnosis trends in states restoring Medicaid dental benefits (California [CA] and Illinois [IL]) with trends in states with constant Medicaid dental benefits. This retrospective, observational study analyzed oral cavity and pharynx cancer case data from The Surveillance, Epidemiology, and End Results program (2004-2017). The outcome was a binary variable indicating whether a patient was diagnosed at a distant stage. Subgroup analyses were conducted by state, race/ethnic group, sex, age, and county-level household income. The sample included 109,997 adults diagnosed with cancer of the oral cavity and pharynx. Restoring Medicaid dental benefits was associated with a statistically significant 2.7%-point decline in the probability of a distant-stage oral cancer diagnosis. This estimate represented a 14% relative change from baseline rates. Results were consistent for CA and IL and by county-level median income. Estimates were significantly larger for adults under age 65, males, and adults identifying as Hispanic; non-Hispanic Black; American Indian; or Asian American or Pacific Islander. Restoring Medicaid dental coverage improved early detection in both CA and IL, with the greatest reductions in distant-stage diagnoses occurring in younger adults, males, and minoritized racial/ethnic groups. Future research should investigate whether earlier detection reduces oral cancer mortality disparities.