Screening History and 7-Year Survival in 32,099 Colorectal Cancer Patients: A Population-Based Cohort Study.

Background: It is unclear whether colorectal cancer screening history, regardless of stage, is an independent predictor of survival, and if the screening advantage persists after diagnosis. 32 099 patients with colorectal cancer were enrolled in this population-based cohort study. Methods: We used data from the Taiwan Cancer Registry on patients with a first-time diagnosis of colorectal cancer between 2013 and 2015. In addition, we utilized data from a nationwide database of colorectal cancer screening programs to evaluate patients' screening histories, and sourced outcome data from the National Death Registry, tracking patients up to the last day of 2019. Results: Compared with fecal immunochemical testing (FIT)-positive patients with a follow-up examination, the adjusted hazard ratios (95% confidence intervals) for death from colorectal cancer were 1.40 (1.26-1.56) for FIT-positive patients without a follow-up examination, 1.63 (1.48-1.78) for FIT-negative patients, and 1.76 (1.65-1.89) for never screened patients. The adjusted hazard ratios for the FIT-positive patients with a follow-up examination increased when diagnosis was delayed by more than 12 months and were 1.2 after a 2-year delay. The adjusted hazard ratios for FIT-negative patients were approximately 2.0, decreased rapidly to 1.6, and stabilized after the 9th time-to-diagnosis month. Conclusion: In colorectal cancer patients, screening history prior to diagnosis is an independent prognostic factor, regardless of cancer stage or other variables. This study recommends that physicians take screening history into account during diagnosis to optimize follow-up and management for patients at higher risk.