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

 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.

 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.

 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.

 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.