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ORIGINAL RESEARCH article

Front. Oncol.

Sec. Gastrointestinal Cancers: Colorectal Cancer

Citywide Community-Based Colorectal Cancer Screening in Urban Shanghai: Age and Sex Variations in Risk Mitigation from 1973 to 2020

Provisionally accepted
Mengyin  WuMengyin WuYangming  GongYangming GongChunxiao  WuChunxiao WuPeng  PengPeng PengChen  LeiChen LeiLi  QiLi QiLiang  ShiLiang ShiYongmei  XiangYongmei XiangJianming  DouJianming DouYi  PangYi PangXiaocong  ZhangXiaocong ZhangKai  GuKai GuYan  ShiYan Shi*
  • Shanghai Municipal Center for Disease Control and Prevention (SCDC), Shanghai, China

The final, formatted version of the article will be published soon.

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.

Keywords: colorectal cancer, screening, trend, interrupted time-series analysis, Epidemiological study

Received: 17 Sep 2025; Accepted: 25 Nov 2025.

Copyright: © 2025 Wu, Gong, Wu, Peng, Lei, Qi, Shi, Xiang, Dou, Pang, Zhang, Gu and Shi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Yan Shi

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