Abstract A052: Insurance status is a predictor of mode of colon cancer detection but not stage at diagnosis: What this means for early detection
Authors: Carnahan Leslie R. , Jones Lindsey , Brewer Katherine , Rauscher Garth H. 
Published: August 2020

Background: Colon cancer is among the most incident and one of the most common causes of cancer-related mortality in the United States. Regular screening is the primary method of preventing excess colon cancer-related morbidity and mortality. Self-reports of on-schedule screening through endoscopy were much higher among insured individuals in the US compared to those without insurance (57% versus 24%) in 2015. Privately insured colon cancer patients are more likely to be diagnosed at earlier stages than patients who are uninsured or on Medicaid. Insurance status may influence whether colon cancer is detected via screening or symptomatic discovery and can impact the likelihood of a late versus early stage diagnosis. Insurance may also influence access to initial follow-up care, which could impact the timeliness of diagnosis and/or treatment.

Objective: We examined patterns of health insurance continuity/discontinuity leading up to a colon cancer diagnosis, as well as associations between insurance status and three outcomes: mode of cancer detection (screen-detected versus symptomatic), diagnosis stage, and clinical delay.

Methods: The Colon Cancer Patterns of Care in Chicago examined racial and SES disparities in colon cancer screening, care initiation and treatment, and diagnostic stage. Eligible patients were non-Hispanic (NH) Black and NH White, aged 50 and older, with colon cancer, and were recruited from nine urban health care institutions. After consent, participants completed an in-person interview wherein they were asked about health insurance access and timing of coverage during diagnosis and treatment and the 5 years prior, diagnostic pathways, treatment, sociodemographic characteristics, and health care utilization. Logistic regression with marginal standardization was used to model the association between insurance variables and colon cancer outcomes. Nonresponse weights were included in all analyses.

Results: After adjusting for age, race, gender and SES, being uninsured any time five years prior to diagnosis or during diagnosis or treatment was associated with a 20-percentage-point (95% CI: 0.08, 0.33) increased prevalence of symptomatic detection. Symptomatic detection in turn was associated with a 15-percentage-point increase in late-stage diagnosis (95% CI: 0.03, 0.27); however, 47% of screen-detected patients were nonetheless diagnosed at a late stage (stage 3 or 4). As a result, insurance status was not associated with stage at diagnosis. Insurance status was also not associated with clinical delay.

Discussion: For health insurance to effectively prevent late-stage colon cancer diagnosis, adults must not only utilize their insurance benefit to get screened, but also screening must have a strong association with early-stage detection. Findings highlight the need to further study and intervene on factors contributing to late-stage colon cancer diagnoses despite screen detection.

Citation Format: Leslie R. Carnahan, Lindsey Jones, Katherine Brewer, Garth H. Rauscher. Insurance status is a predictor of mode of colon cancer detection but not stage at diagnosis: What this means for early detection [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr A052.