In an opinion essay published in Annals of Internal Medicine, several European clinicians argue that the current colorectal cancer screening recommendations by the U.S. Preventive Services Task Force lack strength and quality of evidence.
“We are surprised by the latest update of the recommendations for colorectal cancer screening from the U.S. Preventive Services Task Force (USPSTF),” Michael Bretthauer, MD, PhD, from the KG Jebsen Center for Colorectal Cancer at the University of Oslo in Norway, and colleagues wrote. “Contrary to the principles of evidence-based medicine, the guidelines provided equally strong recommendations for tests with very different quality of evidence for benefits and harms.”
Bretthauer and colleagues note that despite the screening tests differing significantly in mode of action, invasiveness and quality of evidence for effectiveness and cost-effectiveness, the USPSTF graded all tests as a single test.
They also point out that guaiac-based fecal occult blood testing (FOBT) and sigmoidoscopy were the only two strategies recommended by the USPSTF for colorectal cancer screening that offered high-quality data. The remaining five strategies — colonoscopy, fecal immunochemical testing (FIT), computed tomography colonography, FIT DNA testing and a combination of sigmoidoscopy and annual FIT — have not been tested in clinical effectiveness trials, yet are as strongly recommended as FOBT and sigmoidoscopy. Bretthauer and colleagues reason that these strong recommendations may be justifiable even though they present low quality of evidence for benefits; however, the USPSTF did not give an explanation.
In addition, the authors highlight the fact that the USPSTF recommendation of sigmoidoscopy in combination with annual FIT screening did not correspond with trial data. Mortality from colorectal cancer was not significantly different in sigmoidoscopy alone vs. sigmoidoscopy plus FIT. The combined strategy demonstrated a trend toward better effectiveness; sigmoidoscopy alone demonstrated a trend toward better incidence. Furthermore, the experts emphasize that the recommended sigmoidoscopy plus annual FIT has not been tested in any of the trials mentioned.
“To generate high-quality evidence for effectiveness of new screening strategies, we consider the integration of high-quality clinical trials into ongoing screening programs as the only viable solution,” Bretthauer and colleagues wrote.
“We hope these trials will give some of the answers we lack to provide individuals, decision makers, and health care workers with the evidence base needed for informed decision making,” they concluded. “We believe that guideline makers have an important role in facilitating this development and encourage them to participate in the process.” – by Alaina Tedesco
Disclosure: The authors report no relevant financial disclosures.