From the Guidelines
Cologuard, a DNA cancer test by Exact Sciences, is a highly sensitive non-invasive screening tool for colorectal cancer, with a 1-time sensitivity for CRC of 92%, making it an appropriate option for patients seeking a high-sensitivity test, particularly those in the 50- to 65-year age group. The test combines a fecal immunochemical test (FIT) with markers for abnormal DNA, and its advantages include the highest single-time testing sensitivity for cancer of any non-invasive, non-imaging CRC screening test, as well as a 40% sensitivity for sessile serrated polyps (SSPs) >1 cm in size 1. However, the test also has some disadvantages, including a substantial decrease in specificity, particularly in persons aged >65 years, and high cost relative to FIT, with a cost of approximately $600 for privately insured patients and about $500 for Medicare patients 1. Despite these limitations, Cologuard may be a useful option for patients who are reluctant to undergo colonoscopy, potentially leading to earlier detection and improved outcomes for colorectal cancer.
Some key points to consider when using Cologuard include:
- The test is recommended every three years for eligible patients, compared to annual testing for traditional FIT tests 1
- A positive Cologuard result requires follow-up with a diagnostic colonoscopy 1
- The test is not intended for high-risk individuals with a personal or strong family history of colorectal cancer, inflammatory bowel disease, or certain hereditary syndromes
- Cologuard offers a convenient screening option that may increase participation rates among patients who are reluctant to undergo colonoscopy, potentially leading to earlier detection and improved outcomes for colorectal cancer 1.
It's also important to note that annual FIT is more effective and less costly than FIT–fecal DNA every 3 years, so the FIT–fecal DNA test is unlikely to replace FIT in large organized screening programs 1. However, for patients seeking a non-invasive test with very high sensitivity for cancer, Cologuard may be a suitable option, particularly in the 50- to 65-year age group, where the test has better specificity 1.
From the Research
Role of Cologuard in Colorectal Cancer Screening
- Cologuard, a multi-target stool DNA test developed by Exact Sciences, has been shown to be effective in detecting colorectal cancer and advanced precancerous lesions 2.
- A study published in The New England Journal of Medicine found that Cologuard had a sensitivity of 92.3% for detecting colorectal cancer, compared to 73.8% for fecal immunochemical testing (FIT) 2.
- Cologuard also detected more advanced precancerous lesions, including polyps with high-grade dysplasia and serrated sessile polyps, than FIT 2.
Comparison with Other Screening Methods
- A study published in Gastroenterology compared the effectiveness of Cologuard with other screening methods, including blood-based biomarkers, FIT, and colonoscopy 3.
- The study found that Cologuard was more effective than blood-based biomarkers in reducing colorectal cancer incidence and mortality, but less effective than colonoscopy and FIT 3.
- Another study published in Abdominal Radiology discussed the importance of cancer prevention in addition to cancer detection, and highlighted the role of Cologuard in colorectal cancer screening 4.
Sensitivity and Specificity of Cologuard
- A study published in Clinical Colorectal Cancer found that Cologuard had a sensitivity of 63.5% for detecting invasive colorectal cancer, and a specificity of 96.2% in patients with no colorectal lesions or diminutive polyps 5.
- The study also found that Cologuard had a higher sensitivity for detecting advanced adenomas than fecal occult blood testing (FOBT) 5.
Future Directions
- A study published in the World Journal of Gastroenterology discussed the role of different examination methods in colorectal cancer screening, and highlighted the need for improved adherence to screening guidelines 6.
- The study suggested that Cologuard and other non-invasive screening methods could play an important role in improving colorectal cancer screening rates and reducing mortality 6.