Trends in the age-related incidence of colon and rectal cancers in China, 2005–2015

Recent evidences showed that the incidence of colorectal cancer decreased among older adults, yet this decline didn't appear in adults younger than 50 years. Our aim was to evaluate age-related incidence trends of colon and rectal cancers in China during 2005-2015.A retrospective study of colon and rectal cancers was conducted using population-based data from the Chinese Cancer Registry Annual Report. Age at diagnosis was analyzed in five sub-groups (0-19, 20-34, 35-49, 50-64 and 65 years). Data including new cases, incidence, and age-standardized rates (ASRs) were classified by sex and area. Temporal trends of ASRs were determined with Joinpoint regression analysis.From 2005 to 2015, colon cancer incidence decreased by -2.2% (95%CI: -3.1, -1.3) per year. A more steady decrease was seen in rectal cancer with AAPC of -0.9% (95%CI: -1.4, -0.4). Stratified by age at diagnosis, incidence trends followed a similar pattern, without age-related disparity. Females showed pronounced declines relative to males. The exception was that rural individuals showed opposite increasing trends, with 2.7% of AAPCs for colon cancer and 2.0% for rectal cancer.A slight decline was observed in colon and rectal cancers during 2005-2015, regardless of age at diagnosis.