Incidence of Mortality and Associated Factors Among Colorectal Cancer Patients at Oncology Units of Northwest Ethiopia: A Retrospective Cohort Study

BACKGROUND: Colorectal cancer is one of the commonest types of malignant neoplasm with an estimated 935,000 deaths in 2020 worldwide. In Ethiopia, colorectal cancer is the third most common cancer with an incidence of 8/100,000 person-years. Despite studies related to the burden of colorectal cancer, data of mortality related to colorectal cancer are limited and unknown in the study areas. Therefore, the aim of this study was to assess the incidence of mortality and associated factors among colorectal cancer patients who were followed-up at oncology units of Northwest Amhara hospitals, Ethiopia. METHODS AND MATERIALS: A retrospective cohort study was conducted among 367 study participants from January 1, 2017, to December 31, 2020 at oncology units of Northwest Amhara hospitals. Data were entered into EPi-data 4.2.0.0 and transferred to STATA version 14 statistical software for statistical analysis. The Cox regression model was used to identify factors associated with mortality. All variables with P-value < 0.2 during bi-variable analysis were considered for multivariable Cox regression model and level of statistical significance was declared at P value ≤ 0.05. RESULTS: The overall incidence of colorectal cancer mortality was 22.5 per 100 person-years (95% CI: 18.5, 27.38). Being male [AHR =1.60; 95% CI (1.03, 2.48)], having rural residence [AHR=1.68; 95% CI (1.11, 2.55)], carcinoembryonic antigen level ≥5ng/mL [AHR=1.84; 95% CI: (1.02, 3.30)], delay to first health care visit [AHR=1.97; 95% CI (1.19, 3.25)], delay to confirmed diagnosis [AHR=2.45; 95% CI (1.22, 4.90)], and patients who had recurrence after treatment [AHR=1.61;95% CI (1.05, 2.47)] were independently associated with mortality. CONCLUSION: Incidence of colorectal cancer mortality was high. Sex, residency, carcinoembryonic antigen level, time to health care visit, time to confirmed diagnosis, and recurrence significantly increased incidence of mortality. Therefore, creating awareness of colorectal cancer and expanding cancer treatment centers could have paramount importance in reducing the burden of mortality.