Citywide community-based colorectal cancer screening in urban Shanghai: age and sex variations in risk mitigation from 1973 to 2020

Abstract

Aims To evaluate the impact of Shanghai’s community colorectal cancer (CRC) screening program on CRC epidemiology and risk reduction. Materials and methods Data from the Shanghai Cancer Registry (1973-2020) were analyzed. Launched in 2013, the program targets residents aged 50-74, offering free risk assessment (questionnaire and fecal tests). High-risk individuals are advised for colonoscopy (non-mandatory). Interrupted time-series analysis assessed age-standardized incidence and mortality trends. Results Over 3 million individuals were screened, with 18.7% high-risk and 27-32% undergoing colonoscopy. Screening did not significantly reduce CRC incidence but led to a mortality decline (annual percent change [APC]: 1.07% to −3.16%, P < 0.001). Females showed greater benefit, with incidence APC dropping from 1.93% to −0.28% ( P < 0.001). No incidence reduction was seen in younger or older groups, with under-50s showing rising incidence. However, elderly mortality decreased significantly (APC: 1.47% to −3.03%, P < 0.001). Conclusion The program significantly reduced CRC mortality, particularly in females and the elderly, though incidence trends varied by age. Despite a significant reduction in mortality, the observed stability in overall CRC incidence is an expected finding in the initial years of a screening program. This pattern is largely due to increased detection of prevalent pre-existing cases during the first screening round, which may temporarily offset the decline in incident cases.

Related Publications