Colon cancer test
Pro Research Analysisby 
Searched over 200M research papers
Consensus Meter
Advances in Colon Cancer Testing: A Comprehensive Overview
Hemoccult Test: Sensitivity and Specificity
The Hemoccult test, a guaiac-based fecal occult blood test (gFOBT), has been extensively studied for its effectiveness in colorectal cancer (CRC) screening. The Minnesota Colon Cancer Control Study revealed that rehydrating the slides before processing increased the test's sensitivity from 80.8% to 92.2%, but decreased its specificity from 97.7% to 90.4% and positive predictivity from 5.6% to 2.2%. The test's specificity was found to be lower in men compared to women and decreased with age, while positive predictivity increased with age.
Stool-Based Tests: FIT and Fecal DNA Testing
Stool-based tests, including the fecal immunochemical test (FIT) and fecal DNA tests, offer noninvasive CRC screening options. FIT, which detects blood in the stool, is recommended every two years for average-risk adults. Fecal DNA tests, such as the multitarget stool DNA (mt-sDNA) test, analyze stool for human DNA shed from colonic lesions. The mt-sDNA test has shown a sensitivity of 92% for CRC detection, higher than FIT's 74%, but with lower specificity (87% vs. 95%). These tests are convenient and can increase screening rates due to their noninvasive nature.
Colonoscopy: The Gold Standard
Colonoscopy remains the gold standard for CRC screening due to its high sensitivity and ability to detect and remove polyps during the procedure. A study comparing colonoscopy with FIT found that while both detected similar rates of CRC, colonoscopy identified more advanced adenomas (1.9% vs. 0.9%) and nonadvanced adenomas (4.2% vs. 0.4%). Despite its invasiveness and need for bowel preparation, colonoscopy's comprehensive nature makes it a critical tool in CRC prevention.
Computed Tomographic Colonography (CTC)
CTC, also known as virtual colonoscopy, is a less invasive alternative to traditional colonoscopy. A multicenter trial found that CTC had a similar sensitivity to colonoscopy for detecting CRC and large polyps, but required additional follow-up investigations more frequently (30% vs. 8.2%). CTC missed one CRC case out of 29, while colonoscopy missed none. Despite these limitations, CTC offers a viable option for patients who cannot undergo traditional colonoscopy.
Flexible Sigmoidoscopy
Flexible sigmoidoscopy (FS) examines the lower part of the colon and is less invasive than a full colonoscopy. It is recommended every ten years, often in combination with FIT every two years. FS has shown a sensitivity of 77.8% and specificity of 83.9% for advanced colonic lesions. However, it may miss lesions in the proximal colon, which would be detected by a full colonoscopy.
Emerging Blood-Based Tests
Recently, the FDA approved a blood-based test, Epi proColon®, for CRC screening. This test aims to increase participation and adherence rates by offering a less invasive option compared to stool-based tests and colonoscopy. Blood-based tests could play a significant role in improving CRC detection and prevention, especially in populations with low screening adherence.
Conclusion
Advances in CRC screening have provided multiple options ranging from noninvasive stool-based tests to the gold-standard colonoscopy. Each method has its strengths and limitations, and the choice of test should be tailored to individual patient needs and risk factors. Continued research and development of new screening technologies, such as blood-based tests, hold promise for increasing screening rates and early detection of CRC, ultimately reducing mortality from this prevalent disease.
Sources and full results
Most relevant research papers on this topic