In 2023, an estimated 153,020 individuals will be diagnosed with colorectal cancer, underscoring the urgency of effective screening and prevention. Early detection through the removal of polyps remains the linchpin for preventing colorectal cancer. While colonoscopy remains the top choice for polyp removal, various alternatives exist, such as stool, blood, and imaging tests. Let’s delve into some popular colorectal cancer screening options that patients may consider.
Who Should Undergo Screening?
Screening is recommended for adults aged 45 to 75, with further consideration for those aged 76 to 85 on an individual basis. Individuals within this age range, assessed as average risk for colorectal cancer, are candidates for the screening modalities described below. Not all screening tests are created equal, and factors like patient preference, comorbidities, and access to care play a role in choosing the best initial option. It’s crucial to inform patients that a positive result in any test requires endoscopic evaluation for a definitive diagnosis and treatment.
Exploring Screening Options
- Guaiac Fecal Occult Blood Testing (gFOBT) – This test detects blood in the stool through an oxidation reaction. While it has proven efficacy in reducing colorectal cancer mortality, it has limitations in detecting advanced adenomas. Patient adherence may be affected by dietary restrictions and medication changes during sample collection.
- Fecal Immunochemical Test (FIT) – FIT is an improvement over gFOBT, detecting the globin component of human hemoglobin. It requires only one stool sample and has higher sensitivity and specificity for colorectal cancer and adenomas compared to gFOBT. Patient adherence tends to be higher, making it a preferred choice over gFOBT.
- FIT-fecal DNA Test (Cologuard): Combining FIT with DNA testing for specific markers, Cologuard enhances specificity. It offers a sensitivity advantage for colorectal cancer and advanced precancerous lesions compared to FIT alone. However, it comes at a higher cost.
- Virtual Colonoscopy (CT Colonography) – While effective and better-tolerated than barium enemas, CT colonography has limitations in detecting smaller polyps and flat, advanced adenomas. Its impact on colorectal cancer incidence or mortality reduction is yet to be established.
- Septin9 Assay (Epi proColon) – This blood test detects methylated Septin 9 DNA associated with colorectal cancer cells. While approved as a last-resort option, it has shown varying sensitivity and specificity in different studies.
- Sigmoidoscopy – This endoscopic procedure offers the advantage of polyp detection and removal with a less intensive bowel preparation. However, its limited reach may miss right-sided colon cancers.
- Colonoscopy – The gold standard in colorectal cancer screening, colonoscopy provides a single-session diagnosis and treatment. Its higher sensitivity for cancer and all classes of precancerous lesions, along with the ability to remove polyps, positions it as the preferred diagnostic approach.
While the screening modalities presented cater to adults without a history of colon polyps or cancers, the debate on the best method for polyp detection persists. Colonoscopy remains the preferred choice for diagnostic exams, particularly in managing benign and premalignant colorectal polyps. For personalized advice on the best screening test for a specific patient, consulting a local GI specialist is recommended.
References
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Dr. Richard Mclean I
A native of College Park, Dr. Mclean is a graduate of Oxford College and Emory University and received his medical degree from Howard University College of Medicine in Washington, D.C. Following his residency at Barnes Jewish Hospital at Washington University School of Medicine in St.Louis, Dr. Mclean completed a gastroenterology fellowship at the University of California in San Francisco, as well as a fellowship in advanced endoscopy at the University of Southern California in Los Angeles. He joined Atlanta Gastroenterology Associates in 2023 and works in the Stockbridge office.
