Trends of Colorectal Cancer Epidemiology and Morphology in Tehran Metropolis, Iran from 2006 to 2015

Objectives: This study aimed at reporting a 10-years trend in epidemiology and morphology of colorectal cancer (CRC) in Tehran Metropolis, using the data of the National Cancer Registry. Methods: The main sources for data collection included pathology, clinical/paraclinical, as well as death registries. The quality assessment of data was performed based on standard protocols and international reference. Age-standardized incidence rates (ASR) per 100 000 were reported at province levels. Results: Totally, 16280 patients with CRC, who were diagnosed from 2006 to 2015 in Tehran Metropolis, were enrolled in the study; 56.86% of cases were male. The ASRs of adenocarcinoma and other morphology types were higher in males than females. The highest and lowest overall ASR (95% confidence interval (CI)) were reported in 2013 and 2006 with the value of 22.46 (95% CI: 21.58 - 23.35) and 5.55 (95% CI: 5.04 - 6.07) per 100 000 person-years, respectively. The average annual percentage change (AAPC) indicated that from 2006 to 2015, the overall ASR had a statistically upward trend with the value of 15.0 (95% CI: 1.80 - 30.00) in total CRC patients. Besides, the AAPC of adenocarcinoma type in males and females was 15.6 (95% CI: 1.10-32.20) and 12.9 (95% CI: 0.60 - 26.60) over the study period, respectively, which showed a significant upward trend. The ASR was much higher in age ≥ 50 years old compared to age 50 years old. Conclusions: The results showed a growing trend in registry coverage in Tehran Province. Tehran is a high-risk area for the incidence of CRC. Cancer control programs need to be adjusted based on the status of cancer incidence in Tehran Province.