Colorectal cancer (CRC) has been the subject of screening guidelines from multiple organizations, creating some confusion among caregivers over which has the highest-quality, evidence-based recommendations. Rather than developing an additional guideline on the topic, the American College of Physicians recently decided that it would be more valuable to provide information to clinicians based on a rigorous review of currently available guidelines.
Making Sense of CRC Literature
My colleagues and I developed this guidance statement using current recommendations from a joint guideline from the American Cancer Society, the U.S. Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology, as well as individual guidelines from the Institute for Clinical Systems Improvement, the U.S. Preventive Services Task Force, and the American College of Radiology. Based on our evaluations, we developed four guidance statements for CRC screening:
1. Clinicians should perform individualized assessment of risk for CRC in all adults.
2. Clinicians should screen for CRC in average-risk adults starting at age 50 and in high-risk adults starting at age 40 or 10 years younger than the age at which the youngest affected relative was diagnosed with CRC.
3. Clinicians should use a stool-based test, flexible sigmoidoscopy, or optical colonoscopy as a screening test in average-risk patients. Optical colonoscopy should be used in high-risk patients. Clinicians should select the test based on the benefits and harms of the test, availability of the test, and patient preferences.
4. Clinicians should stop screening for CRC in adults older than age 75 or in adults with a life expectancy of less than 10 years.
The evidence reviewed in our guidance statement showed that CRC screening helps identify undiagnosed, pre-malignant lesions. Earlier diagnosis of these lesions allows for timely treatment and can therefore reduce mortality. The benefit of reduced mortality outweighs the harms of screening at the ages specified above.
“Patients should be educated on the benefits, harms, effectiveness, safety, and costs associated with each test.”
Because the various CRC tests have similar efficacies, shared decision making is important in selecting a screening test. Patients should be educated on the benefits, harms, effectiveness, safety, and costs associated with each test, as well as how often the test must be performed. For example, stool tests must be done every year to maintain efficacy, whereas colonoscopies should be repeated every 10 years. However, the harms of colonoscopy include perforation and bleeding, whereas a stool-based test has virtually no harm except for false positives or negatives. Therefore, patients’ individual preferences play a significant role in CRC screening methods that are selected.
More Colorectal Cancer Screening, Less Mortality
Currently, only 60% of adults aged 50 or older are screened for CRC in the U.S. With available evidence supporting the effectiveness of screening in reducing mortality, greater efforts are needed to screen more adults. Those who choose colonoscopy will only need to be screened two or three times in a lifetime. Ultimately, patients should be informed of the benefits of CRC screening.
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