Factors related to mortality due to progression of disease in patients with colon cancer in the presence of competing risks: a retrospective cohort study in the west of Iran

Aim: This study aims to identify the risk factors of disease-related death in patients with colon cancer in the presence of competing risks.

Background: Competing risk analysis is an effective method for identifying risk factors of death from disease, and the evidence related to the prognosis of death in patients with colon cancer in the country is rare.

Methods: In this historical cohort study, the information of 196 patients with colon cancer who were referred to Imam Khomeini Clinic in Hamadan during the years 2003 to 2017 were examined. Death due to the progression of cancer was considered an interesting cause, and death related to other causes was considered a competing event. Predictors of death due to the progression of cancer were determined in the presence of competing risks. The cause-specific hazard regression model was used to determine the effects of covariates. Data was analyzed using R software vol. 3.4.3 and survival packages.

Results: The mean (SD) age of patients was 57.1 (12.9) years, and 52.6% were male. The results of the multivariate cause-specific hazard regression model showed that the patient's age at the time of cancer diagnosis, T stage, stage of the disease and N stage had significant effects on the hazard of death due to cancer progression (p<0.05).

Conclusion: In the presence of various causes of death, using the cause-specific hazard model to identify the risk factors of each cause separately can better support clinical decisions compared to other models.