Background: The incidence of young-onset colorectal cancer (CRC) is reported to be increasing in the Western world. There are no population-based studies assessing the trend across Asia.
Methods: We performed a multinational cohort study involving four Asian countries/regions, namely Taiwan, Korea, Japan, and Hong Kong. The magnitude and direction of trend in the incidence of young-onset CRC (age < 50) were quantified using Joinpoint Regression Program to estimate average annual percentage change (AAPC).
Results: In Taiwan (1995-2014), incidence of young-onset CRC significantly increased in both men (colon cancer: 4.9-9.7 per 100,000; rectal cancer: 4.0-8.3 per 100,000) and women (colon cancer: 5.1-9.7 per 100,000; rectal cancer: 3.8-6.4 per 100,000). In Korea (1999-2014), incidence of young-onset CRC significantly increased in both men (colon cancer: 5.0-10.4 per 100,000; rectal cancer: 4.9-14.0 per 100,000) and women (colon cancer: 4.1-9.6 per 100,000; rectal cancer: 4.1-9.1 per 100,000). The most pronounced change was observed with male rectal cancer, increasing by 3.9% per year in Taiwan (AAPC + 3.9, 95% confidence interval + 3.3 to +4.5, P < 0.05) and 6.0% per year in Korea (AAPC +6.0, 95% confidence interval + 4.5 to +7.6, P < 0.05). Only a significant increase in rectal cancer was noted in Japan (male rectal cancer: 7.2-10.1 per 100,000, female rectal cancer 4.7-6.7 per 100,000) and Hong Kong (male rectal cancer: 4.4-7.0 per 100,000).
Conclusions: Increasing trend in young-onset CRC is not limited to the Western world. This finding may have implications on screening program for CRC in these countries/regions.