Making sense of colorectal cancer screening choices

Colorectal cancer is the third most common cause of cancer death among men and women in the U.S. But there is shockingly large regional variation in mortality, in part because of sharp differences in the provision of effective screening programs.

Figure: Prevalence of cancer screening by colonoscopy within 10 years, sigmoidoscopy within 5 years, or fecal occult blood testing within the past year (Berkowitz et al.)The U.S. Preventive Services Task Force now recommends no less than eight different screening approaches for average-risk individuals, beginning at age 50. Finding no head-to-head studies to compare effectiveness, the panel reasoned that any method of screening is more beneficial than no screening at all.

To help patients and providers choose the most appropriate screening strategies for colorectal cancer, the OHSU health system has drafted a new guideline that ranks the recommended options into two tiers: preferred options and acceptable alternatives. This approach takes into consideration test performance, adverse events, patients’ needs, and local availability.

“Although the Preferred Option tests are chosen for their sensitivity and/or cost-effectiveness of screening, the tiered approach allows the opportunity to offer other tests if a patient declines a Preferred Option test,” the authors explained.

Colorectal cancer is one of the most amenable to prevention, and screening has contributed to a steady decline in the incidence since the mid-1980s. Screening makes it possible to detect not only early-stage cancers but also precancerous lesions, which, when removed, may prevent tumors from developing.

The new guideline lists two preferred screening strategies for average-risk individuals: colonoscopy at 10 year intervals, or annual fecal immunochemical testing (FIT). If a patient declines colonoscopy and FIT, the guideline recommends offering any of three alternative strategies: CT colonography every five years, FIT-fecal DNA every three years, or flexible sigmoidoscopy at intervals of five to 10 years.

Two available tests are not recommended, neither capsule colonoscopy, which uses a miniature wireless camera to record images of the digestive tract, nor the SEPT9 gene methylation assay, the first FDA-approved blood test for colorectal cancer screening.

The guideline was developed by OHSU and Tuality clinicians, under the direction of the Office of Clinical Integration and Evidence-based Practice. OHSU Practice Plan members David Lieberman, M.D., professor of medicine and head of gastroenterology and hepatology, and Daisuke Yamashita, M.D., assistant professor of family medicine, and Tuality physicians Michael Doorly, M.D., and Jeremy Lake, M.D., served as clinical leads on the project.

Further reading:

OHSU Health System  Colorectal Cancer Screening Guideline, Office of Clinical Integration and Evidence Based Practice (February 2018)

Multilevel Small-Area Estimation of Colorectal Cancer Screening in the United States by Zahava Berkowitz, Xingyou Zhang, Thomas B. Richards, Marion Nadel, Lucy A. Peipins and James Holt. Cancer Epidemiology Biomarkers & Prevention (March 1, 2018)