Patients who do not follow a positive fecal immunochemical test (FIT) with a colonoscopy are twice as likely to die from colorectal cancer (CRC) as their counterparts who receive a colonoscopy, according to a study published in Gut. The findings suggest that additional interventions are necessary to increase colonoscopy uptake in patients with a positive FIT result.
For the analysis, researchers conducted a retrospective cohort study using data from an FIT-based CRC screening program in the Veneto region of Italy. The screening program invited adults aged 50 to 69 years to complete an FIT every 2 years. Patients with a positive FIT result (>20 μg Hb/g feces) were referred to an endoscopic center for diagnostic colonoscopy. Data from the years 2004 through 2017 were used to compute 10-year cumulative CRC incidence and mortality rates among patients with a positive FIT result. Outcome rates were compared between patients who completed a diagnostic colonoscopy and patients who did not.
Of participants with a positive FIT result, 88,013 complied with a follow-up colonoscopy and 23,410 did not. The 10-year cumulative incidence of CRC was 44.7 cases per 1000 people (95% CI, 43.1-46.3) among individuals who complied with colonoscopy, compared with 54.3 per 1000 (95% CI, 49.9-58.7) in individuals who did not comply with colonoscopy. Cumulative mortality from CRC was 6.8 per 1000 (95% CI, 5.9-7.6) in patients who received a colonoscopy and 16.0 per 1000 (95% CI, 13.1-18.9) in patients who did not. The estimated risk for dying from CRC during follow-up was twice as high among patients who did not comply, with an adjusted hazard ratio of 2.03 (95% CI, 1.68-2.44).
Results from this analysis underline the importance of follow-up colonoscopies in patients with positive FIT results. As a study limitation, investigators noted that certain confounding factors could not be accounted for, including potential underlying risk factors for CRC in those who did not comply with colonoscopy. Further analysis of colonoscopy uptake may be warranted.
“The effectiveness of FIT-based screening depends on colonoscopy compliance after an initial positive result,” the study authors wrote. “Additional interventions are needed to engage these patients and decrease their burden of CRC.”
Zorzi M, Battagello J, Selby K, et al. Non-compliance with colonoscopy after a positive faecal immunochemical test doubles the risk of dying from colorectal cancer. Gut. Published online February 8, 2022. doi:10.1136/gutjnl-2020-322192