Colorectal cancer is the second leading cause of cancer mortality in the United States.¹ Screening adults 50 years and older for colorectal cancer reduces morbidity and mortality at a reasonable cost. All major cancer and prevention-related organizations recommend universal colorectal cancer screening for adults, even though they may differ on the relative effectiveness of specific screening modalities. Colorectal cancer screening not only reduces disease-specific mortality, it reduces the incidence of colorectal cancer; it is effective as a primary and secondary prevention tool. This set of positive statements about screening can be made only about two cancers: colorectal and cervical.

There are a variety of options for colorectal cancer screening that physicians can recommend to patients. As documented by Wilkins and Reynolds in this issue,² fecal occult blood test (FOBT), flexible sigmoidoscopy, and colonoscopy all have sufficient scientific evidence to support their use. Other promising technologies, such as computed tomographic colonography and fecal DNA testing, are not yet ready for widespread use. There is some doubt about when to start screening persons at high risk of colorectal cancer and what the optimal age is to stop screening. Which test performs the best, when considering benefits and harms, is also debatable. But, one fact is clear—any testing is better than no testing.

With all this good news, why is adherence to screening recommendations not better? In 2006, only 60.8 percent of adults 50 years and older reported having had an FOBT within the past year or lower endoscopy (sigmoidoscopy or colonoscopy) within the past 10 years.³ This is an improvement from 53.9 percent in 2002.³ The proportion of adults who report never being tested was 29.5 percent in 2006, down from 34.2 percent in 2002.³ Although the trends show improvement, significant disparities persist. Racial or ethnic minorities and those with no health insurance, low incomes, or less than a high school education have significantly lower rates of use of colorectal cancer testing.³

There are several hypothesized reasons to explain low adherence to recommendations. These include lack of a medical home, lack of health insurance, lack of awareness of the need, and failure of physicians to recommend screening. Family physicians can address the last two issues; policy makers need to address the first two.

Family physicians should ensure that all adult patients know about the effectiveness of colorectal cancer screening and receive a strong recommendation to undergo testing. Evidence-supported methods of increasing colorectal cancer screening rates include patient reminders, informational brochures, newsletters, videos, and assessment of physician practices with feedback.⁴

There is no safe and effective strategy to prevent colorectal cancer other than polypectomy. There is no proven primary prevention for colorectal cancer other than aspirin and other nonsteroidal anti-inflammatory drugs, which are not recommended because of the risks associated with the doses needed to prevent colorectal cancer.² Genetic testing cannot place anyone in a risk-free category at this time. If patients are reluctant to undergo lower endoscopy, there is a perfectly good alternative—FOBT performed according to recommendations. If colonoscopy is not readily available, sigmoidoscopy with or without FOBT is also acceptable.

Reducing the toll of colorectal cancer will require concerted effort by multiple parties. Physicians need to promote proven screening tools, policy makers should find a way to provide health insurance to all Americans, and community health agencies need to market the effectiveness of screening to the public. The U.S. Preventive Services Task Force and the American Cancer Society recently published revised recommendations for colorectal cancer screening.^5,6 It is likely that these recommendations will continue to have some differences, but those differences will not detract from the main point: colorectal cancer screening works—if we do it.