Background: Socioeconomic status (SES) is known to affect outcomes for various cancers. This has partly been attributed to later stage at presentation, but the association between SES and stage at presentation in gastrointestinal (GI) cancers is not well described. We aim to examine the relationship between SES and stage at diagnosis for five different GI cancers: esophageal, gastric, pancreatic, colon, and rectal. Methods: The Surveillance, Epidemiology, and End Results (SEER) census tract level SES database was queried for the above cancers diagnosed in 2012-2016. This specialized database provides SES quintiles created from a composite SES index developed using the method developed by Yost et al. using census-tract information. Quintile 1 is the lowest while quintile 5 is the highest SES. Cancer stage at diagnosis was defined as early (local/regional) versus late (distant) based on the SEER summary stage. Multivariable analysis examined the effect of SES on diagnosis at late stage of cancer, adjusting for differences in age, race, gender, marital status, and insurance status. Results: A total of 245,462 patients were included in the analysis. Low SES was associated with increased odds of late stage at diagnosis in all sites except stomach. The estimated unadjusted ORs for quintile 1 compare to 5 were 1.21 (95% CI, 1.10-1.33), 1.07 (95% CI, 0.99-1.16), 1.21 (95% CI, 1.15-1.28), 1.19 (95% CI, 1.14-1.24), and 1.34 (95% CI, 1.25-1.44) for esophageal, gastric, pancreatic, colon, and rectal cancer respectively. When SES was examined along with age, race, gender, marital status, and insurance status in the multivariable model, the effect of SES was largely reduced, with only pancreatic and rectal cancers having association between lower SES and late stage at presentation (pancreatic: OR 1.155 [95% CI, 1.068-1.249]; rectal: 1.109 [95% CI, 1.044-1.179]). Being uninsured or having Medicaid insurance was greatly associated with higher odds of late stage at diagnosis in all cancer sites.
The adjusted ORs for late presentations for uninsured compared to insured patients were: 1.66 (95% CI, 1.36-2.01), 1.70 (95% CI, 1.48-1.96), 1.35 (95% CI, 1.19-1.54) 1.54 (95% CI, 1.43-1.67), 1.78 (95% CI, 1.69-2.00) for esophageal, gastric, pancreatic, colon, and rectal cancer respectively. The corresponding ORs for Medicaid compared to insured patients were: 1.08 (95% CI, 0.98-1.20), 1.18 (95% CI, 1.10-1.27), 1.18 (95% CI, 1.12-1.25), 1.25 (95% CI, 1.20-1.31), and 1.56 (95% CI, 1.46-1.66).
Conclusion: Diagnosis of cancer at late stage was closely associated with lack of insurance and having Medicaid insurance. Adjusting for insurance status lessened the association between SES and stage at diagnosis. Efforts to improve cancer outcomes though earlier detection of cancers need to focus on improving insurance coverage for lower SES populations.
Citation Format: Gina A. Kim, Patricia Friedmann, Haejin In. Impact of socioeconomic status on stage at presentation of gastrointestinal cancers [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-225.