Screening for colorectal cancer should begin at age 50 and continue through age 75, using fecal occult blood tests (FOBT), colonoscopy, or a combination of FOBT and endoscopy, according to updated draft recommendations from the U.S. Preventive Services Task Force (USPSTF).
Optionally, screening may continue beyond 75 on an individualized basis. The task force acknowledged a moderate benefit, at best, for screening people 76 to 85, especially if they have never had a screening test for colorectal cancer. The panel recommended against screening patients older than 85, stating that "competing causes of mortality preclude a mortality benefit [from screening] that would outweigh the harms."
"This update reaffirms the Task Force's 2008 'A' recommendation to screen all adults ages 50 to 75 and 'C' recommendation to selectively screen some adults ages 76 to 85," according to a statement from the USPSTF. "Evidence continues to show that screening is most beneficial in adults ages 50 to 75 and that adults ages 76 to 85 are most likely to benefit from screening if they have never been screened before and are healthy enough to undergo treatment, if cancer is found."
The draft recommendations, which are open to public comment through Nov. 2, cite three screening options, which afford similar protection against dying of colorectal cancer, according to data reviewed by the USPSTF panel:
- Annual fecal immunochemical testing (FIT)
- Annual FIT plus flexible sigmoidoscopy every 10 years
- Colonoscopy every 10 years
All three recommended screening methods reduce the risk of colorectal cancer death by detecting early cancers and precancerous adenomatous polyps in the colon. However, the USPSTF pointed out that "to date, no method of colorectal cancer screening has been shown to decrease all-cause mortality in any age group."
The panel did not consider alternative screening intervals or techniques for high-risk individuals (such as people of black race and positive family history), but the USPSTF acknowledges that some specialty organizations recommend that screening begin earlier, continue at more frequent intervals, and employ colonoscopy for patients who have a family history of colorectal cancer.
With regard to the higher risk associated with black race and male sex, the panel concluded that the reasons for the higher risk are not clear. "Accordingly, this recommendation applies to all ethnic and racial groups, with the clear acknowledgement that efforts are needed to ensure that at-risk populations receive recommended screening, follow-up, and treatment."
In weighing the evidence for different types of screening tests, the USPSTF found that the three recommended strategies "yield comparable life-years gained ... and an efficient balance of benefits and harms. An all-colonoscopy strategy yields the most life-years but at a cost of more colonoscopy procedures and associated potential harms. FIT has the lowest life-years yield but also requires fewest colonoscopy procedures and associated harms. The FIT-sigmoidoscopy combination strategy falls in the middle for life-years gained and colonoscopies/harms."
Alternative screening methods, such as CT colonography and FIT-DNA testing, might have a role in specific clinical circumstances, but data are insufficient to support their use in routine screening of average-risk patients, the USPSTF panel concluded.
U.S. Preventive Services Task ForceSource Reference: USPTF "Screening for colorectal cancer: U.S. preventive services task force draft recommendation statement"