What is the recommended screening schedule for an adult of average risk for colorectal cancer using the Fecal Immunochemical Test (FIT)?

Fecal Immunochemical Test (FIT) Screening Schedule

For average-risk adults, FIT should be performed annually starting at age 45-50 years and continuing through age 75 years. 1

Screening Frequency

• Annual FIT testing is the recommended interval across all major U.S. guidelines, including the U.S. Preventive Services Task Force (USPSTF), American Cancer Society (ACS), American College of Physicians (ACP), and U.S. Multi-Society Task Force (MSTF). 1

• The Canadian Task Force on Preventive Health Care recommends FIT every 2 years for adults aged 50-74 years, though this represents an outlier position compared to the predominant global recommendation of annual testing. 1, 2

• FIT is designated as a first-tier screening option alongside colonoscopy every 10 years, with strong recommendation and moderate-quality evidence supporting its use. 1, 3

Age to Begin Screening

• Start FIT screening at age 45 years for all average-risk adults, though this carries a qualified recommendation with moderate certainty. 1, 4

• Screening from age 50-75 years carries the strongest recommendation with the most robust evidence for mortality benefit. 1

• African Americans may benefit from beginning screening at age 45 years based on higher CRC incidence and mortality rates in this population, though this is a weak recommendation with very-low-quality evidence. 1

Age to Stop Screening

• Continue annual FIT through age 75 years in adults with good health and life expectancy greater than 10 years. 1

• For ages 76-85 years, individualize screening decisions based on prior screening history (particularly whether prior colonoscopy was negative), overall health status, and life expectancy exceeding 10 years. 1, 4

• Discontinue screening after age 85 years as harms outweigh benefits regardless of prior screening history. 1, 4

• Stop screening when life expectancy is less than 10 years due to comorbidities, as screening is unlikely to provide benefit. 1, 4

Critical Implementation Requirements

Patient Commitment

• Annual testing commitment is essential - one-time or sporadic FIT testing has very limited sensitivity and makes stool testing a poor screening choice. 2

• Patients must understand that all positive FIT results require immediate follow-up colonoscopy to rule out colorectal cancer or advanced neoplasia. 1, 2, 4, 5

• Without commitment to both annual testing and colonoscopy follow-up for positive results, stool-based screening programs are ineffective. 2, 5

Test Collection Method

• Home-based specimen collection is required for FIT - single-panel FIT performed in the office using a stool sample from digital rectal examination is not recommended due to low sensitivity. 2

FIT Superiority Over gFOBT

• FIT demonstrates 2-3 times higher sensitivity for cancer detection compared to guaiac-based fecal occult blood testing (gFOBT), with cancer detection rates of 75-100% versus 30.8-64.3% for gFOBT. 5, 6

• FIT achieves 27.3-37.7% sensitivity for advanced adenomas compared to only 7.2-15.2% for gFOBT, while maintaining comparable specificity (85.9-96.9% vs 90.1-98.8%). 5, 6

Common Pitfalls to Avoid

• Never use FIT or any stool-based test in symptomatic patients with alarm symptoms including rectal bleeding, narrowed stools, unexplained weight loss, or change in bowel habits - these patients require immediate diagnostic colonoscopy regardless of any screening test results. 4, 5

• Do not use gFOBT when FIT is available - the evidence overwhelmingly favors FIT for both detection rates and patient adherence. 5, 6

• Do not continue screening past age 75 years in patients with adequate prior negative screening history, particularly those with prior negative colonoscopy, as harms increasingly outweigh benefits. 1, 4

• Verify that patients understand FIT is only for average-risk individuals without family history of CRC, inflammatory bowel disease, genetic syndromes, or personal history of CRC or adenomatous polyps - these individuals require different screening protocols. 1, 4

Alternative Screening Strategy

• If patients decline annual FIT, offer colonoscopy every 10 years as the other first-tier screening option with proven mortality benefit. 1, 3

• Second-tier options include CT colonography every 5 years, multitarget stool DNA test (FIT-DNA) every 3 years, or flexible sigmoidoscopy every 5-10 years, though each has disadvantages relative to annual FIT or colonoscopy. 1, 3