The Academy recently streamlined its stance on colorectal cancer screening. While continuing to strongly recommend screening men and women 50 years of age or older for the disease, the new policy gives no specifics on how often screening should be performed or what methods should be used, citing insufficient evidence.
The AAFP Board of Directors approved the revisions, recommended by the Commission on Clinical Policies and Research, in March. Visit "Recommendations for Periodic Health Examinations" and scroll to "Colorectal Cancer" to read the new recommendation and to link to supporting materials. The policy builds on colorectal cancer screening guidance from the U.S. Preventive Services Task Force.
AAFP Colorectal Cancer Policy Keeps Strong Call to Screen, Drops Specifics
Digital In-office FOBT Not Effective in Screening, Says FP
By Cindy Borgmeyer
4/26/2005
Specifically, USPSTF found good evidence that periodic at-home fecal occult blood testing reduced mortality from colorectal cancer; it found fair evidence that sigmoidoscopy alone or in combination with FOBT did so. Although task force members found no direct evidence that screening colonoscopy reduced mortality, the overall efficacy of colonoscopy was supported by other data and evidence of benefit, including the procedure's ability to inspect the proximal colon.
Double-contrast barium enema offered an alternative means of whole-bowel examination but was less sensitive than colonoscopy and also showed no direct evidence of effectiveness in reducing mortality, the USPSTF found. Data were insufficient to indicate whether newer technologies such as computed tomographic colography improved outcomes.
Although USPSTF members agreed that the benefits of colorectal cancer screening substantially outweighed potential harms, they acknowledged the quality of evidence, magnitude of benefit and potential harms varied among screening methods. Overall, they concluded, screening was likely to be cost-effective regardless of the strategy chosen.
Meanwhile, one FP expert points an accusing finger at in-office FOBT. According to Michael Potter, M.D., of San Francisco, the test -- specifically, the one-shot version many physicians perform in the course of an office visit -- "has no place as a screening test for colorectal cancer."
"Some physicians may just figure this is the easiest way to get screening done while they have the patient in the office," Potter says of primary care physicians who tack on a digital rectal exam with a fecal occult blood test at the end of a pelvic exam, for example. "There is the perception that it might be better than nothing, but the evidence shows that most likely it is not better than doing nothing."
An associate clinical professor in the Department of Family and Community Medicine at the University of California, San Francisco, Potter serves on the Quality Assurance Subcommittee of the National Colorectal Cancer Roundtable and recently received a Cancer Control Career Development Award for Primary Care Physicians from the American Cancer Society.
The roundtable is a coalition of more than 50 public and private organizations collaborating to increase colorectal cancer testing rates and overall disease awareness. The coalition was co-founded by ACS and CDC in 1997.
Although USPSTF members agreed that the benefits of colorectal cancer screening substantially outweighed potential harms, they acknowledged the quality of evidence, magnitude of benefit and potential harms varied among screening methods. Overall, they concluded, screening was likely to be cost-effective regardless of the strategy chosen.
Meanwhile, one FP expert points an accusing finger at in-office FOBT. According to Michael Potter, M.D., of San Francisco, the test -- specifically, the one-shot version many physicians perform in the course of an office visit -- "has no place as a screening test for colorectal cancer."
"Some physicians may just figure this is the easiest way to get screening done while they have the patient in the office," Potter says of primary care physicians who tack on a digital rectal exam with a fecal occult blood test at the end of a pelvic exam, for example. "There is the perception that it might be better than nothing, but the evidence shows that most likely it is not better than doing nothing."
An associate clinical professor in the Department of Family and Community Medicine at the University of California, San Francisco, Potter serves on the Quality Assurance Subcommittee of the National Colorectal Cancer Roundtable and recently received a Cancer Control Career Development Award for Primary Care Physicians from the American Cancer Society.
The roundtable is a coalition of more than 50 public and private organizations collaborating to increase colorectal cancer testing rates and overall disease awareness. The coalition was co-founded by ACS and CDC in 1997.
"If you do an in-office fecal occult blood test and it’s normal, that person walks out of your office with the same likelihood of having colorectal cancer as someone who didn't get screened."
-- Michael Potter, M.D.
-- Michael Potter, M.D.
Potter points to two studies published in the Jan. 18 Annals of Internal Medicine as confirming his reservations. Visit "Accuracy of Screening for Fecal Occult Blood on a Single Stool Sample Obtained by Digital Rectal Examination: A Comparison With Recommended Sampling Practice" and "A National Survey of Primary Care Physicians' Methods for Screening for Fecal Occult Blood" to read the article abstracts.
Among the studies' conclusions:
Among the studies' conclusions:
- A single result from digital FOBT "is a poor screening method for colorectal neoplasia and cannot be recommended as the only test."
- When performed as part of a primary care exam, a negative digital FOBT result does not correlate with a decreased risk of having advanced neoplasia.
- Decreased mortality seen with use of FOBT in carefully controlled clinical trials often is not replicated in community practice because of the common use of in-office tests and inadequate follow-up.
- "While it's true there is a menu of screening options that includes FOBT as a valid option, many clinicians appear not to have gotten the message that acceptable fecal occult blood screening does not include the in-office version," Potter explains.
Granted, at-home tests have their drawbacks, Potter admits. "It's hard to get more than 50 percent of people to complete the test," he says. "It involves dietary changes for a few days, and many people have a phobia about handling their own stool." There are newer immunochemical fecal occult blood tests that may be easier to use than the standard test, he adds, but they are not yet in widespread use in the United States.
The take-home for family physicians, Potter notes, is not to be lulled into a false sense of security by a negative in-office FOBT result on a single, digitally procured sample.
"Don't be reassured by that," he warns. "Don't tell the patient, 'You’ve been screened and you're OK.' If you do an in-office fecal occult blood test and it’s normal, that person walks out of your office with the same likelihood of having colon cancer as someone who didn't get screened."
The take-home for family physicians, Potter notes, is not to be lulled into a false sense of security by a negative in-office FOBT result on a single, digitally procured sample.
"Don't be reassured by that," he warns. "Don't tell the patient, 'You’ve been screened and you're OK.' If you do an in-office fecal occult blood test and it’s normal, that person walks out of your office with the same likelihood of having colon cancer as someone who didn't get screened."
