Background: Despite progress in colorectal cancer (CRC) screening and treatment over the past two decades, striking disparities in CRC survival persist among racial/ethnic minorities, with Blacks experiencing a 10% lower 5-year overall survival compared to Whites (American Cancer Society, 2017). One potential reason for the disparity in survival may be due to lower rates of appropriate surveillance care among racial/ethnic minorities. Among CRC patients, postoperative surveillance (PS) received at recommended intervals within 5-years following surgery improves overall survival up to 33% (Rodríguez-Moranta, 2006). Unfortunately, minority CRC survivors are approximately 30% less likely to receive PS compared to non-Hispanic Whites (NHW) (Carpentier, 2013). There are likely multiple underlying factors contributing to disparities in the timely receipt of recommended PS procedures such as colonoscopy, a PS procedure with adherence proportions as low as 18% among CRC patients. The differences in CRC patients who adhere or do not adhere to PS procedures are understudied.

Purpose: Based on Andersen's (1978, 1995, 2007) Behavioral Model of Health Services Use, this study will assess the association between individual- and contextual-level factors and adherence to PS colonoscopy among Medicare beneficiaries from different racial/ethnic groups.

Methods: This is a retrospective population-based cohort study using the SEER-Medicare linked database (2009-2014). Medicare beneficiaries diagnosed with CRC as their first cancer and who received surgical resection for CRC stage II and III, and who are between the ages of 66 and 85, are included in this sample. Chi-squared test will be used to assess significant differences in the distribution of patient characteristics across race/ethnicity, and analysis of variance (ANOVA) is used to assess differences for age as a continuous variable. Descriptive statistics will be presented for all demographic and socioeconomic variables to describe the characteristics of the sample population, stratified by racial/ethnic group. A hierarchical generalized linear model will be used to assess adherence to PS colonoscopy as a nonlinear function of explanatory variables defined at the individual- and contextual-levels. The adjusted odds with 95% confidence intervals of adherence to PS colonoscopy also will be presented by racial/ethnic group.

Conclusions: Appropriate surveillance following a CRC diagnosis is critical for improving CRC outcomes. Characteristics that are unique to racial/ethnic minorities may contribute to lower rates of adherence to PS colonoscopy, leading to poor survival outcomes. Findings from the proposed research may help guide future public health and clinical interventions focused on improving the timely receipt of PS procedures among older adults.

Citation Format: Janeth Sanchez, Veena Shankaran, Joseph Unger, Margaret Madeleine, Beti Thompson. Sociodemographic predictors of adherence to postoperative surveillance colonoscopy among patients diagnosed with nonmetastatic colorectal cancer [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 C006.