AUTHOR=Wu Mengyin , Gong Yangming , Wu Chunxiao , Peng Peng , Chen Lei , Li Qi , Shi Liang , Xiang Yongmei , Dou Jianming , Pang Yi , Zhang Xiaocong , Gu Kai , Shi Yan 

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

JOURNAL=Frontiers in Oncology

VOLUME=Volume 15 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2025.1707133

DOI=10.3389/fonc.2025.1707133

ISSN=2234-943X

ABSTRACT=AimsTo evaluate the impact of Shanghai’s community colorectal cancer (CRC) screening program on CRC epidemiology and risk reduction.Materials and methodsData 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.ResultsOver 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).ConclusionThe 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.