Abstract
Background Colorectal cancer (CRC) screening programs based on fecal immunochemical testing (FIT)
generate substantial pressure on colonoscopy capacity in Europe. Thus, a relevant
proportion of FIT-positive patients undergo colonoscopy after the recommended 30-day
interval, which may be associated with an excess CRC risk.
Methods In a cohort of 50–69-year-old patients undergoing biennial rounds of FIT (OC-Hemodia
latex agglutination test; cutoff 20 µg hemoglobin/g feces) between 2004 and 2017,
we assessed the outcome at colonoscopy (low/high risk adenoma/CRC/advanced stage CRC)
among FIT-positive patients, according to different time intervals. The association
of each outcome with waiting time, and demographic and clinical factors, was analyzed
through multivariable analysis.
Results 123 138/154 213 FIT-positive patients (79.8 %) underwent post-FIT colonoscopy. Time
to colonoscopy was ≤ 30 days, 31–180 days, and ≥ 181 days in 50 406 (40.9 %), 71 724
(58.3 %), and 1008 (0.8 %) patients, respectively. At colonoscopy, CRC, high risk
adenoma, and low risk adenoma were diagnosed in 4813 (3.9 %), 30 500 (24.8 %), and
22 986 (18.7 %) patients, respectively. An increased CRC prevalence at colonoscopy
was observed for a time to colonoscopy of ≥ 270 days (odds ratio [OR] 1.75, 95 % confidence
interval [CI] 1.15–2.67), whereas it was stable for waiting times of < 180 days. The
proportion of advanced CRC also increased after 270 days (OR 2.79, 95 %CI 1.03–7.57).
No increase for low or high risk adenomas according to time to colonoscopy was observed.
Conclusion In a European FIT-based screening program, post-FIT colonoscopy after 9 months was
associated with an increased risk of CRC and CRC progression.
