Ethnic and Clinical Disparities in Colorectal Cancer Outcomes in Sabah, Malaysia: A Population-based Study (2015–2020)

Background Colorectal cancer (CRC) is a major cause of cancer-related mortality worldwide. In Malaysia, CRC is the most diagnosed cancer among men and the second most common among women. Sabah, characterized by ethnic diversity and healthcare access disparities, lacks population-level data on CRC outcomes. This study aimed to evaluate ethnic and clinical disparities in CRC incidence, survival, and relapse in Sabah and to assess the impact of tumor stage and treatment delay on prognosis. Methodology : A retrospective cohort analysis of 450 histologically confirmed CRC patients from the Sabah Cancer Registry (2015–2020) was conducted. Kaplan-Meier methods were used to estimate overall and relapse-free survival, while multivariate regression models identified predictors of mortality and relapse. Results The median age at diagnosis was 62 years, with males comprising 55.3% of patients. Chinese patients accounted for 34.3% of cases, followed by Kadazan-Dusun (25.3%) and Bajau (18.8%). Most patients (59.9%) presented with advanced-stage disease. The five-year overall survival was 23.2%, and the median relapse-free survival was 24 months. Treatment delay beyond 60 days and diagnosis at advanced stage were significant predictors of both relapse and mortality. Ethnic disparities were observed in unadjusted outcomes but were no longer significant after adjustment for clinical and geographic variables. Conclusions The findings underscore the need for regionally tailored screening programs, timely treatment pathways, and equitable oncology services to improve CRC outcomes in Sabah. Strengthening early detection and post-treatment surveillance is critical to addressing structural barriers and reducing disparities across Sabah’s diverse population.