Insurance Status and Cancer Stage at Diagnosis Prior to the Affordable Care Act in the United States.

PURPOSE: Previous studies on insurance and cancer stage at diagnosis are limited by either insufficient power for less common cancers or nonpopulation-based samples. We aimed to examine this association using a nationwide population- based sample of patients for a wide range of cancer sites prior to implementation of the Affordable Care Act (ACA) in the United States.

METHODS: A total of 1,233,045 incident cancer patients aged 18-64 years diagnosed in 2007-2011 from 35 US central cancer registries were analyzed. Prevalence ratios and 95 percent confidence intervals for the effect of insurance status (uninsured, Medicaid, Medicare, or private) on disease stage at diagnosis for 14 cancer sites were estimated using log-binomial models. A stratified analysis by states' status on Medicaid expansion was conducted.

RESULTS: Uninsured or Medicaid patients had a higher risk of being diagnosed with advanced stage (III/IV) than privately insured patients for most cancer types, with the associations most prominent for diseases, such as melanoma and female breast cancer, that can potentially be detected early by either symptom assessment or screening services. The associations were similar between Medicaid expanding states and nonexpanding states.

CONCLUSIONS: The new association estimates for multiple cancers provided in our study can be used as baselines for future monitoring and evaluation of the impact of the ACA on cancer care and outcomes.