How effective is the Fecal Immunochemical Test (FIT) compared to a colonoscopy in detecting colorectal cancer?

From the Guidelines

Colonoscopy is superior to FIT for detecting colon cancer, though both have important roles in screening. When considering the detection of colon cancer, it's essential to weigh the benefits and limitations of each screening method. Colonoscopy can detect approximately 95% of colorectal cancers and large polyps, while FIT typically detects about 70-80% of cancers but is less effective at finding precancerous polyps, identifying only about 20-30% of advanced adenomas 1.

Key Differences Between Colonoscopy and FIT

• Colonoscopy allows direct visualization of the entire colon and immediate removal of polyps during the procedure, effectively preventing cancer before it develops.
• FIT is a non-invasive stool test that checks for hidden blood in the stool, which can be an early sign of cancer.
• FIT needs to be performed annually, whereas colonoscopy is typically done every 10 years for average-risk individuals.
• The advantage of FIT is that it is more convenient, requires no preparation or sedation, and carries no procedural risks, making it a good option for those who refuse colonoscopy or have contraindications to the procedure.

Recommendations

• Colonoscopy is recommended as the primary screening method for colon cancer due to its high detection rate and ability to prevent cancer through polyp removal.
• FIT can be considered as an alternative for individuals who refuse colonoscopy or have contraindications to the procedure, as it is still an effective screening method for detecting colon cancer 1.
• Patient preference should be considered when making recommendations, as the best screening test is ultimately the one that gets done 1.

Considerations

• The American College of Physicians guideline recommends using structural methods, such as colonoscopy, when possible, due to their ability to detect adenomatous polyps and cancer 1.
• The US Multi-Society Task Force on Colorectal Cancer recommends using FIT as a screening method, especially for individuals who are at average risk for colorectal cancer 1.

From the Research

Comparison of FIT and Colonoscopy

• The Fecal Immunochemical Test (FIT) and colonoscopy are two different methods used for colon cancer screening, with varying levels of sensitivity and specificity 2, 3, 4.
• Colonoscopy is considered the gold standard for detecting colorectal precancerous lesions and has a high sensitivity for precancerous lesions of all sizes 5.
• FIT, on the other hand, is a stool-based test that detects blood in the stool, which can be an indication of colon cancer 2, 3, 4.
• While colonoscopy has a higher sensitivity for detecting colon cancer, FIT is a less invasive and more accessible test, making it a suitable option for average-risk individuals 2, 3, 4.

Detection Capabilities

• Colonoscopy has been shown to have a high yield for detecting polyps and can reduce the incidence and mortality of colon cancer 5, 6.
• FIT, while less sensitive than colonoscopy, can still detect colon cancer and has been recommended as a screening option for average-risk individuals 2, 3, 4.
• The choice between FIT and colonoscopy ultimately depends on individual preferences, risk factors, and medical history 2, 3, 4.

Screening Guidelines

• Current guidelines recommend screening for colon cancer starting at age 45 for average-risk individuals, with options including FIT, colonoscopy, and other screening modalities 2, 3, 4.
• High-risk individuals, such as those with a family history of colon cancer, may require more frequent or earlier screening 3.
• The American Cancer Society and other organizations recommend a combination of screening tests, including FIT and colonoscopy, for optimal detection and prevention of colon cancer 2, 6.