Time trends of incidence and mortality in colorectal cancer in Changning District, Shanghai, 1975-2013

OBJECTIVE: To evaluate the incidence and mortality of colorectal cancer (CRC) and the estimated patient's age, diagnostic duration and birth cohort effects in patients of Changning District, Shanghai. METHODS: Age-standardized rates (ASRs) of CRC over eight intervals of 5 years from 1975 to 2013 were determined. Joinpoint regression analysis was used to determine the changes in annual incidence and mortality trends. Age-period-cohort analysis was performed to investigate their effects on the incidence and mortality trends of CRC. RESULTS: For incidence, the ASRs of 14.14 per 100 000 and 11.81 per 100 000 during 1975-1979 increased to 32.11 per 100 000 and 26.25 per 100 000 in men and women during 2008-2013. For mortality, ASRs of 9.40 per 100 000 and 8.76 per 100 000 increased to 14.80 per 100 000 and 11.92 per 100 000 in men and women, respectively, from 1975-1979 to 2010-2013. Joinpoint regression analysis found an increasing incidence (average annual percentage change [AAPC] 2.18% for men and 1.65% for women) and mortality (AAPC 1.47% for men and 0.97% for women) of CRC throughout the entire period. The incidence and mortality trends of CRC were significantly affected by birth cohorts. CONCLUSIONS: The increasing incidence and mortality of CRC are largely affected by the effects of birth cohorts. The increased incidence of CRC may be attributed to changes in lifestyle and diet, while that in mortality trends may be resulted from increasing incidence, an aging population and changing lifestyles.