Risk of ulcerative colitis-associated colorectal cancer in China: a multi-center retrospective study

The number of patients with ulcerative colitis (UC) in China has increased in the past 10 years. Thus, it is anticipated that the incidence of UC-associated colorectal cancer (UC-CRC) will also increase. However, the risk of CRC in UC patients is still unknown in Chinese. The aim of this study was to identify the risk and risk factors of UC-CRC in Chinese.

A total of 3,922 patients with UC were retrospectively collected from five central teaching hospitals in China, in which high-quality endoscopic and histological diagnoses were available from 1998 to 2009. The database of the UC and UC-associated CRC patients was evaluated.

CRC was diagnosed 34 in patients, and the overall prevalence of CRC in patients with UC was 0.87%. The cumulative risk of developing CRC after a disease duration of 10 years was 1.15% (95% confidence interval [CI] 0.71-1.84%); 20 years, 3.56% (95% CI 2.14-5.89%); and 30 years, 14.36% (95% CI 7.57-26.3%). Longer disease duration, extensive colitis, and dysplasia found in the biopsy specimen were identified as risk factors for developing CRC. 5-ASA use was identified as a protective factor of UC-CRC.

The period prevalence of CRC was lower than that reported from the West. However, the cumulative risk was found to be comparable to that of Western countries, which suggests that the period prevalence of UC-CRC in China may be growing in the future.