Failure to undergo colonoscopy after positive FIT may double risk for death from colorectal cancer

Failure to undergo a diagnostic colonoscopy after receiving positive results on a fecal immunochemical test (FIT) was associated with twice the colorectal cancer (CRC) mortality rate, a study found.

Researchers reviewed data from a FIT-based CRC screening program in Italy, in which patients ages 50 to 69 years with a positive FIT result were referred for diagnostic colonoscopy. The retrospective cohort study compared the 10-year cumulative incidence and mortality among FIT-positive patients who completed a diagnostic colonoscopy within the program and those who did not. Results were published online March 30 by Gut.

Overall, 88,013 patients who tested positive on FIT had subsequent colonoscopy, whereas 23,410 did not. The 10-year cumulative incidence of colorectal cancer in those who had a colonoscopy was 44.7 per 1,000 (95% CI, 43.1 to 46.3) versus 54.3 per 1,000 (95% CI, 49.9 to 58.7) in those who did not. CRC mortality in these groups was 6.8 per 1,000 (95% CI, 5.9 to 7.6) and 16.0 per 1,000 (95% CI, 13.1 to 18.9), respectively. The risk for dying of CRC was 103% greater in those who did not have a colonoscopy than among those who did (adjusted hazard ratio, 2.03; 95% CI, 1.68 to 2.44).

The study's finding of excess risk for death from CRC in patients who did not have recommended colonoscopy after a positive FIT result should prompt screening programs to adopt effective interventions that increase colonoscopy adherence, the study authors concluded.

“Though the proportion of deaths attributable to CRC was similar in compliers (9.6%) and non-compliers (8.5%), the higher overall mortality in non-compliers means that the absolute difference in CRC-specific mortality remains important,” they wrote. “Because non-compliers are a group at high risk of death, and a high proportion of these deaths are attributable to CRC, they should be encouraged to have a procedure that may be lifesaving.”