What is the comparison between Colonoscopy and Fecal Immunochemical Test (FIT)?

From the Guidelines

Colonoscopy every 10 years is the preferred screening method for average-risk individuals, while annual FIT is a suitable alternative, particularly in organized screening programs or for those who decline colonoscopy. When comparing Colonoscopy and Fecal Immunochemical Test (FIT) for colorectal cancer screening, it's essential to consider the advantages and disadvantages of each method. Colonoscopy involves direct visualization of the entire colon, allowing for detection and removal of precancerous polyps in a single procedure, and is typically performed every 10 years 1. FIT, on the other hand, is a non-invasive stool test that detects hidden blood in the stool, which may indicate colorectal cancer or large polyps, and is performed annually at home 1. Key differences between the two methods include:

• Invasiveness: Colonoscopy is an invasive procedure that requires bowel preparation, dietary restrictions, and sedation, while FIT is non-invasive and requires no preparation.
• Sensitivity: Colonoscopy is more sensitive than FIT, allowing for the detection and removal of precancerous polyps.
• Convenience: FIT is more convenient and can be performed at home, while colonoscopy requires a visit to a medical facility.
• Risk factors: Colonoscopy is preferred for those with higher risk factors, such as a family history of colorectal cancer or personal history of polyps, while FIT may be better for those who cannot undergo colonoscopy due to medical reasons or strong preference against invasive procedures 1. Ultimately, the best screening test is the one that gets done, and patient preference should be considered when making this decision. Considerations for screening include:
• Age: Screening should begin at age 50 years in asymptomatic persons, but may be started earlier in individuals with higher risk factors or African Americans 1.
• Life expectancy: Discontinuation of screening should be considered when patients reach age 75 years or have a life expectancy of less than 10 years 1.
• Comorbid conditions: Screening should be considered up to age 85 years, depending on comorbid conditions and life expectancy 1.

From the Research

Comparison of Colonoscopy and Fecal Immunochemical Test (FIT)

• The Colonoscopy vs. Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM) study 2 is a large, pragmatic, multicenter, randomized, parallel group trial to compare screening with colonoscopy vs. the annual fecal immunochemical test (FIT) in 50,000 average risk individuals.
• The study aims to examine whether screening colonoscopy will be superior to a FIT-based screening program in the prevention of CRC mortality measured over 10 years.
• Another study 3 compared single CT colonography versus three rounds of faecal immunochemical test for population-based screening of colorectal cancer and found that greater participation makes FIT more efficient than single CT colonography for detection of advanced neoplasia in population screening for colorectal cancer.

Patient Preferences

• A national survey 4 found that more respondents preferred multi-target stool DNA (mt-sDNA) test over colonoscopy, and FIT/gFOBT over colonoscopy.
• The survey also found that certain demographic characteristics and awareness of and/or experience with various screening modalities influenced preferences.
• Another study 5 used conjoint analysis to update the understanding of people's CRC screening test preferences in the context of new guidelines and found that the most preferred test was a fecal immunochemical test (FIT)-fecal DNA every 3 years.

Equivalency of FIT and Colonoscopy

• A controlled randomized trial 6 compared the efficacy of repeated fecal immunochemical tests (FITs) and colonoscopy in detecting advanced neoplasia in family members of patients with CRC and found that repeated FIT screening (1/year for 3 years) detected all CRCs and proved equivalent to colonoscopy in detecting advanced neoplasia.
• The study suggests that FIT strategy should be considered for populations where compliance with FITs is higher than with colonoscopy.

Key Findings

• The detection rate for advanced neoplasia of CT colonography was significantly lower than the detection rate after three FIT rounds 3.
• The referral rate to work-up optical colonoscopy was significantly lower for the CT colonography group than for the FIT group after three FIT rounds 3.
• More than one-third of people may want to do a FIT-fecal DNA every 3 years for their CRC screening 5.
• Three-fourths of people may prefer an annual FIT over colonoscopy when only considering US MSTF tier 1 tests 5.