In 2002, the U.S. Preventive Services Task Force recommended colorectal cancer screening for adults 50 years of age or older.
However, the task force concluded that evidence was insufficient to prioritize among screening tests or evaluate newer tests, such as computed tomographic colonography.
Dr Evelyn Whitlock reviewed evidence related to knowledge gaps identified by the 2002 recommendation, and considered community performance of screening endoscopy, including harms.
Eligible studies reported performance of colorectal cancer screening tests or health outcomes in average-risk populations.
The team noted that the studies were at least of fair quality according to design-specific U.S. Preventive Services Task Force criteria.
The research team reported that 2 reviewers verified extracted data.
|Serious harm occurred in 3 per 1000 screening colonoscopies|
|Annals of Internal Medicine|
The researchers found 4 fecal immunochemical tests have superior sensitivity, and some have similar specificity, to the Hemoccult II fecal occult blood test.
Tradeoffs between superior sensitivity and reduced specificity occur with high-sensitivity guaiac tests and fecal DNA, with other important uncertainties for fecal DNA.
The team noted that in settings with sufficient quality control, computed tomographic colonography is as sensitive as colonoscopy for large adenomas and colorectal cancer.
Uncertainties remain for smaller polyps and frequency of colonoscopy referral.
The team did not find good estimates of community endoscopy accuracy.
The research team observed serious harms occurring in 3 per 1000 screening colonoscopies, and are 10-fold less common with flexible sigmoidoscopy.
The accuracy and harms of screening tests were reviewed after only a single application.
Dr Whitlock’s team concluded, “Fecal tests with better sensitivity and similar specificity are reasonable substitutes for traditional fecal occult blood testing.”
“However, modeling may be needed to determine all tradeoffs.”
“Computed tomographic colonography seems as likely as colonoscopy to detect lesions 10 mm or greater but may be less sensitive for smaller adenomas.”
“Potential radiation-related harms, the effect of extracolonic findings, and the accuracy of test performance of computed tomographic colonography in community settings remain uncertain.”
“Emphasis on quality standards is important for implementing any operator-dependent colorectal cancer screening test.”