Does ethnicity affect survival following colorectal cancer? A prospective, cohort study using Iranian cancer registry

BACKGROUND The present study compared the differences between survivals of patients with colorectal cancer according to their ethnicity adjusted for other predictors of survival. METHODS In this prospective cohort study patients were followed up from definite diagnosis of colorectal cancer to death. Totally, 2431 person-year follow-ups were undertaken for 1127 colorectal cancer patients once every six months. The data were analyzed by stata software using bivariate analysis, multivariate analysis, and Cox regression. RESULTS The age at diagnosis was significantly different between men and women (p<0.03). 61.2% were male and the rest were female. Most patients were Fars (51.2%), followed by Turciks (21.5%), Kurds (8.2%), and 7.5% Lurs. Of the patients, 75% had a survival of more than 2.72 years, 50% a survival of 5.83 years, and 25% longer than 13.1 years after diagnosis. Risk ratio was significantly different among ethnics (p<0.05). The variables of ethnicity, being non married, tumor grade, family history of cancer, and smoking were considered as determinants of the patients' survival in Cox regression model. The median survival time in Fars, Kurds, Lurs, Turks and other ethnics was 5.83, 2.44, 5.49, and 8.52 years, respectively. CONCLUSION Ethnicity and access to healthcare are predictors of survival of patients with colorectal cancer which may define priorities in controlling cancer and implementing interventional and prevention plans.