Joinpoint analysis trends in the incidence of colorectal cancer in Khon Kaen, Thailand (1989 - 2012)

Objective: This study focused on recent changes in the incidence of colorectal cancer (CRC) in Khon Kaen, Thailand. Methods: Data for CRC over the period 1989 to 2012 from the population-based cancer registry of Khon Kaen province were employed. Age-standardized incidence rates (ASR) were calculated and classified into 4 age-groups for comparison. Joinpoint regression analysis was used to detect changes in trends among each line segment and an overall line was generated, whether increasing or decreasing, with annual percent change (APC) and average annual percent change (AAPC). Results: There were 3,364 CRC cases included in the analysis, 72.2% histological confirmed and 53.5% in men. Trends of ASRs generally demonstrated gradual increase over the period 1989 to 2012. For those aged under 45 or 50 years there was slight overall increase, with a somewhat zigzag pattern. From joinpoint analysis, the trends of all aged groups were found to be increasing among both men and women: aged 45 years and older group AAPC=3.40, 2.30 and 3.90, respectively); aged 50 years and older group AAPC=2.90, 2.20 and 3.40; aged under 45 years AAPC=6.30, 6.00 and 6.90; and aged under 50 years (AAPC=5.70, 3.20 and 5.70. Conclusions: ASRs for CRC have been gradually increasing in the northeast region of Thailand. Future studies should consider the subsite distribution.