Abstract B133: Disparities in survival by sociodemographic factors among patients with young-onset colorectal cancer: A population-based study
Authors: Martinez Maria Elena , Gomez Scarlett Lin , Canchola Alison J , Murphy James D , Demb Joshua , Nodora Jesse N , Gupta Samir 
Published: September 2020

Background: According to the Surveillance, Epidemiology, and End Results Program, the annual percent change in colorectal cancer (CRC) incidence increased by 3.6% from 2013 to 2016 in individuals less than 50 years of age. Data on survival after young onset CRC diagnosis, including differences by sociodemographic characteristics, are lacking. We assessed differences in CRC survival according to sociodemographic factors, including race/ethnicity, sex, health insurance type, and neighborhood socioeconomic status (nSES) in patients under the age of 50 years at CRC diagnosis. Methods: The study included male and female CRC cancer cases under 50 years old, diagnosed from 2000-2015 and followed through 2016 in the California Cancer Registry. Analysis included 21,128 patients and 6,269 CRC deaths. Multivariable Cox proportional hazards regression was used to generate hazard ratios (HR) and 95% confidence intervals (CI) for risk of CRC-specific mortality. Multivariable models were stratified by American Joint Committee on Cancer (AJCC) stage (to account for hazard non-proportionality), and adjusted for age at diagnosis, year of diagnosis, race, sex, tumor size, tumor subsite, tumor grade, marital status, insurance status type, NCI-designated cancer center, nSES, neighborhood percent NH black, urban/rural, and clustering by block group. Results: Compared to non-Hispanic Whites (NHW), risk of dying from CRC was higher in Blacks (HR=1.21; 95% CI, 1.09-1.34) but not in Hispanics (HR=0.98; 95% CI, 0.92-1.05) nor Asian/Pacific Islanders (API) (HR=1.03; 95% CI, 0.96-1.11). CRC mortality was lower in female compared to male patients (HR=0.87; 95% CI, 0.83-0.92). Higher CRC mortality was observed for patients on Medicaid (HR=1.41; 95% CI, 1.31-1.50) and those with no insurance HR=1.32; 95% CI, 1.15-1.52), as compared to privately insured patients. An increase in CRC mortality associated with lower nSES was observed (HR=1.39; 95% CI, 1.25-1.54 for lowest compared to highest statewide quintile; P-trend &lt;0.0001). Conclusion: Results corroborate recent reported disparities in young-onset CRC survival between Blacks and Whites. Our findings further point to higher mortality in patients who are not privately insured and those living in lower SES neighborhoods. Further studies that integrate biological and molecular factors are needed to advance our understanding of CRC mortality in younger patients.

Citation Format: Maria Elena Martinez, Scarlett Lin Gomez, Alison J Canchola, James D Murphy, Joshua Demb, Jesse N Nodora, Samir Gupta. Disparities in survival by sociodemographic factors among patients with young-onset colorectal cancer: A population-based study [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B133.