Fecal Test Aids Colonoscopy Screening

When compared to guaiac fecal occult blood testing (gFOBT), FIT assays have similar or even lower costs and may reduce mortality from colorectal cancer.

Scientists at the Erasmus Medical Center (Rotterdam, the Netherlands) used the MISCAN-Colon microsimulation model, which simulates the relevant biographies of a large population from birth to death both without screening, as well as with changes that would occur in screening programs. They estimated the number of colonoscopies, costs, and health effects of different screening strategies using gFOBT and FIT, various age ranges and multiple surveillance strategies.

The model predicts that FIT is both cost-effective and clinically beneficial for detecting colon rectal cancer (CRC). They found that for a screening scenario for people ages 45 to 80 years in which there is unlimited colonoscopy capacity, screening intensively with the lowest FIT cutoff level for referral to colonoscopy of 50 ng hemoglobin/mL, provided optimal health benefits for cost. For a scenario with limited colonoscopy capacity, FIT with a higher cutoff level performed better than gFOBT and was more effective if the colonoscopy capacity was expanded.

In many countries, wait times for colonoscopy screenings can take up to 12 weeks. Screening with gFOBT has been proven to reduce mortality from CRC. However, the effectiveness of the screening depends partly on attendance at all screening rounds and on diagnostic yield, which is the proportion of individuals found with adenomas or CRC. FIT may increase attendance and diagnostic yield compared to gFOBT, and may cause fewer false positive tests. Because of these advantages, FIT is of increasing interest in the field.

The authors concluded, "It should be noted that FOBT screening can become considerably more effective if colonoscopy capacity is expanded. Efforts should therefore be undertaken to achieve an increased colonoscopy capacity.” The study was published on November 9, 2011, in the Journal of the National Cancer Institute.

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