What is the yield of a screening program based on fecal immunochemical testing every 2 years for 10 years?

Over a 10-year period, the rates of detection of colorectal cancer (CRC) and advanced adenomas using fecal immunochemical testing (FIT) are similar to those seen in studies of screening colonoscopy. This is reassuring, but it does not prove that FIT reduces morbidity and mortality due to CRC as effectively as colonoscopy. Modeling concludes that a FIT-based screening program will result in half as many colonoscopies as a program based on colonoscopy, a significant reduction in cost, burden, and harm of screening. (LOE = 2b)

Zorzi M, Hassan C, Capodaglio G, et al. Long-term performance of colorectal cancer screening programmes based on the faecal immunochemical test. Gut 2018;67(12):2124-2130.  [PMID:29101260]

Cohort (prospective)

Government

Population-based

The 2 most widely recommended strategies for CRC screening are FIT and colonoscopy. Several trials are currently underway to compare these approaches, with cancer-specific mortality as the primary outcome. Until then, we have to rely on observational studies and modeling to understand the benefit of each approach. Although colonoscopy is more sensitive than FIT, especially for the detection of advanced adenomas, what matters is performance over a long-term screening program, not one-time accuracy. This study reports the results of 5 rounds of biennial FIT in a screeening population aged 50 to 69 years in the Veneto region of northern Italy. Not surprisingly, the rate of detection of CRC was highest in the first round of screening when prevalent lesions were detected (3.3/1000 persons), declining in subsequent rounds and stabilizing after the third round (~1/1000 persons). Between rounds 3 and 6, the CRC detection rate declined slightly from 0.95 to 0.84 per 1000. A similar pattern was seen for advanced adenomas, declining from 15.9 per 1000 persons to approximately 10 per 1000 persons in subsequent rounds. Over the 10-year study period, the cumulative rate of positive FIT results was 25% for men and 17.6% for women. The cumulative rate for advanced adenoma was 60 per 1000 persons, and for CRC was 8.5 per 1000 persons. These rates are similar to those seen in studies of colonoscopy in both Italy and the United States.