Our aim was to examine the association between fatal colorectal cancer (CRC) and time to colonoscopy among individuals who underwent diagnostic colonoscopy after abnormal stool blood test (SBT) in a cohort of United States Veterans. Methods: We performed a cohort study of Veterans aged 50–75 years, with an abnormal SBT using the Veterans Health Administration's (VA) national electronic health record data during the years 1999 and 2010. Colonoscopy receipt was ascertained using current procedural terminology codes after abnormal SBT. The study outcome, CRC death, was defined through National Death Index cause-specific mortality data. We followed patients through CRC-related death, other death, or until December 31, 2015. Multivariable Cox proportional hazards modeling was used to generate CRC-specific mortality hazard ratios (HRs) and 95% confidence intervals (CI) for 3-month colonoscopy intervals, with 3–6 months as the reference. Models were adjusted for age, sex, race/ethnicity, smoking, diabetes, body mass index, and Charlson Comorbidity Index. Results: We included 222,004 patients with abnormal SBTs; the average age was 63 with a standard deviation of 7.2 years, 97% were male, 72% were Non-Hispanic White and 20% were Black. Of the 222,004 patients, 69% completed diagnostic colonoscopy within 12 months of abnormal SBT, 4% were diagnosed with CRC, and 1% died of CRC specific death. Compared to patients with a colonoscopy at 3–6 months (standard of care), CRC-related mortality risk was significantly higher for patients with colonoscopies at 0–3 months (HR = 1.29; 95% CI, 1.14–1.47), 18–21 months (HR = 1.57; 95% CI, 1.19–2.06), and 21–24 months (HR = 1.46; 95% CI, 1.07–1.97). No significant increase in mortality risk was shown for 6–9 month, 9–12 month, 12–15 month, 15–18 months, and 24+ month intervals. Conclusion: Time to colonoscopy plays a significant role in CRC death after abnormal SBT. Compared to a colonoscopy performed during a 3–6-month window, a colonoscopy performed outside of the 15-month window had a higher risk for mortality. Given the impact of timely diagnostic colonoscopy on CRC mortality, development of interventions to increase timely diagnostic follow-up after abnormal SBT are essential to CRC outcome improvement.

The following are the 17 highest scoring abstracts of those submitted for presentation at the 44th Annual ASPO meeting held March 22–24, 2020, in Tucson, AZ.