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IARC 60th Anniversary - 19-21 May 2026

Session : 19/05/26 - Posters

Screening intervals after a negative colonoscopy in high-risk populations: evidence from a colorectal cancer screening program

WEIWEI C. 1, LE W. 2, YUNFENG Z. 3, XUESI D. 4, LIJUAN D. 1, FURONG C. 1, NI L. 4, DONG H. 1,5, LINGBIN D. 2

1 Nanjing Medical University, Nanjing, China; 2 Zhejiang Cancer Hospital, Hangzhou , China; 3 Haining Hospital of Traditional Chinese Medicine, Haining, China; 4 Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; 5 Changzhou Medical Center, Changzhou, China

Background
Guidelines recommend a 10-year colorectal cancer (CRC) rescreening interval after a negative colonoscopy for average-risk individuals, while its suitability for those with a positive fecal immunochemical test (FIT) or questionnaire-based risk assessment (QRA) remains uncertain.

Objectives
This study aimed to determine the optimal rescreening interval following a negative colonoscopy among FIT- or QRA-positive individuals.

Methods
Individuals were recruited from a screening program conducted in Haining County, Zhejiang Province, China, from 2007 to 2021. Individuals aged 40 to 74 years were invited to provide two fecal samples for FIT and to complete a standardized questionnaire for QRA. Those with a positive result on either QRA or FIT were further advised to undergo a free colonoscopy. In this study, individuals with a positive FIT or a QRA but negative colonoscopy (no adenoma or CRC detected) were included in the analyses. Multivariable Cox regressions were used to estimate the association between rescreening at different intervals and CRC risk. Time-dependent Cox regression and landmark analysis were conducted to mitigate immortal time bias. Among those receiving colonoscopy at rescreening, the prevalence of colorectal lesions was compared across interval groups.

Results
A total of 24,379 individuals with a positive FIT or QRA but a negative colonoscopy were included, of whom 17,026 underwent a subsequent screening (Figure 1A). Over a mean follow-up of 7.2 years, 98 CRC cases were diagnosed. Individuals who attended a rescreening had a lower risk of CRC than those who did not (hazard ratio (HR) = 0.39, 95% confidence interval (CI): 0.24–0.65). Notably, compared with no rescreening, rescreening at 5–7 years was associated with a lower CRC risk (HR, 0.33; 95% CI, 0.19–0.57), with consistent associations in both FIT-positive (HR, 0.33; 95% CI 0.17–0.64) and QRA-positive subgroups (HR, 0.23; 95% CI 0.09–0.60) (Figure 1B). Results were robust in time-dependent and landmark analyses. Among those undergoing colonoscopy at rescreening, the proportion of advanced neoplasia was lower at 5–7 years (2.12%) than at 7–10 years (4.62%; P < 0.001), with no difference compared with ≤5 years (1.75%; P = 0.851).

Conclusions
Individuals with a positive FIT or QRA but a negative colonoscopy may benefit most from repeat screening at 5–7 years.

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Figure 1. Flowchart of study population (A) and the Association between subsequent screening and CRC risk among individuals with a positive FIT or QRA but a negative colonoscopy (B).