In a guidelines update, the American Cancer Society (ACS) on Wednesday recommended that adults aged 45 years and older with an average risk of Colorectal cancer (CRC) undergo regular screening with either a high‐sensitivity stool‐based test or a structural (visual) examination, depending on patient preference and test availability. As a part of the screening process, all positive results on noncolonoscopy screening tests should be followed up with timely colonoscopy.
The recommendation to begin screening at age 45 years is a qualified recommendation.
The recommendation for regular screening in adults aged 50 years and older is a strong recommendation.
The ACS recommends that average‐risk adults in good health with a life expectancy of greater than 10 y continue CRC screening through the age of 75 years (qualified recommendation).
The ACS recommends that clinicians individualize CRC screening decisions for individuals aged 76 through 85 years based on patient preferences, life expectancy, health status, and prior screening history (qualified recommendation).
The ACS recommends that clinicians discourage individuals over age 85 years from continuing CRC screening (qualified recommendation).
Options for CRC screening
• Fecal immunochemical test every year
• High‐sensitivity, guaiac‐based fecal occult blood test every year
• Multitarget stool DNA test every 3 years
• Colonoscopy every 10 years
• CT colonography every 5 years
• Flexible sigmoidoscopy every 5 years
Colorectal cancer is the second-leading cause of cancer death in the United States, most frequently diagnosed among adults over 65. To catch those typically slow-growing malignancies early, when they can often be cured, most doctors’ groups recommend colorectal cancer screening starting at age 50.
But the American Cancer Society this week changed its advice and is now recommending that screening start five years earlier.
The ACS Guideline Development Group (GDG), a multidisciplinary panel of volunteers comprising generalist clinicians, biostatisticians, epidemiologists, economists, and a patient representative, is charged with the development and update of the ACS cancer screening guidelines. The GDG has full responsibility for interpretation of the evidence, formulating the recommendations, deliberation and voting on the recommendations and strength, and writing the guideline.
“Individuals with recognized clinical and research expertise in the areas of CRC natural history, detection, diagnosis, and decision making were invited to advise the GDG and to provide broader knowledge and understanding of the complexity of CRC screening” ACS said.
So far, other groups are maintaining their recommendation that colon cancer screening start at age 50, including the U.S. Preventive Services Task Force, an independent, volunteer panel of national experts in disease prevention and evidence-based medicine.
Stanford University internist Douglas K. Owens, the task force’s vice-chairperson, says the group’s 2016 recommendations were based on extensive review of the benefits and harms of colorectal screening at the time.
“There was limited data on screening people under age 50,” Owens says. The new American Cancer Society guidelines, he adds, should prompt more research into the relative benefits and harms of screening among younger people.
Ongoing studies are looking at a multitude of factors that might be contributing to the earlier cancer occurence. Potential culprits include over-the-counter anti-inflammatory medicines, antibiotics and antidepressants, as well as multiple vitamins, probiotics and other dietary supplements.
A first colon cancer screening does not have to be a colonoscopy. In its new recommendations, the cancer society recommends choosing from one of six screening tests, which are also currently recommended by other expert groups. The guidelines don’t prioritize among screening choices.
The choices include three at-home kits that test stool for blood.
If the test is positive, a colonoscopy is recommended.
Typically, these home tests of feces are repeated every year for good results.
Alternatively, some patients opt for what’s called a “virtual” colonoscopy — essentially a CT scan of the colon — which should be done every five years, according to the new recommendations.
Another approved option is a flexible sigmoidoscopy, which looks at the lower part of the colon, and is followed up by a colonoscopy if polyps are found.
A positive result picked up in these screening tests is typically followed up by a colonoscopy, which uses a tiny camera to investigate the entire colon. It is not only a search for early cancer; more often than not it detects pre-malignant, suspicious lesions, or polyps, which are removed during the procedure.
“When we find and remove polyps we actually prevent any future chance of that developing into cancer,” he says.
The American Cancer Society says it endorsed the full range of screening tests “without preference” in order to improve the rate of screening. In its latest advice, the U.S. Preventive Services Task Force says head-to-head comparison studies have shown that no one screening test is more effective than another in early cancer detection.
While they differ on the age of first screening, both groups suggest that screening over age 75 should be a joint decision between patient and doctor. And after age 85, screening is no longer necessary, the doctors’ groups agree. That’s because the risk of colonoscopy among this elderly population can outweigh any benefit.