Recent findings indicate the colonoscopy may cause more harm and incur more costs than it's worth. Add this to the growing list of tests, such as the PSA, that provide small benefits and high risk to the patient.  Overdiagnosis is a major problem in colonoscopy screening.

The United States adopted a primary colonoscopy strategy for colorectal cancer screening despite a lack of strong evidence that its benefits surpass those of other strategies.

The use of colonoscopy as the primary screening strategy for colorectal cancer in the United States, which has been famously dubbed "going the distance," might be a case of going too far, suggests an editorial published online November 9 in the Journal of the National Cancer Institute.

The benefits, harms, and costs of this primary colonoscopy strategy system have not been fully explored or analyzed — and they need to be, say editorialists Russell Harris, MD, MPH, and Linda S. Kinsinger, MD, MPH, from the University of North Carolina in Chapel Hill.

"Randomized controlled trials show that screening with fecal occult blood tests (FOBT) and flexible sigmoidoscopy reduces mortality from colorectal cancer, but there is much less evidence about the magnitude of any additional benefit from colonoscopy," the editorialists write.

Nevertheless, screening with colonoscopy — which was called "going the distance" by Daniel Podolsky, MD, from the University of Texas Southwestern Medical Center in Dallas, in an influential essay in 2000 (N Engl J Med. 2000;343:207-208) — is recommended as the primary strategy by major professional associations, such as the American College of Gastroenterology and the National Comprehensive Cancer Network, they point out.

"We in the United States need to revisit the logic that 'going the distance' for everyone is better than less intensive screening," write Drs. Harris and Kinsinger.

The cost and harms of the strategies also need to be quantified more precisely in any comprehensive analysis, they add.

"It may be that such an analysis would find that the incremental benefits (which for colonoscopy are uncertain) of a primary colonoscopy program, compared with a primary stool test and/or flexible sigmoidoscopy strategy, do not outweigh the incremental harms and costs," they write.

"The new analyses may show that primary colonoscopy screening is best limited to subgroups," the editorialists note. They speculate that "for most of the population, going the distance may well provide small benefits with larger costs and harms."

Drs. Harris and Kinsinger also raise an issue that has been a lightning rod for criticism of breast and prostate cancer screening: overdiagnosis. "The issue of overdiagnosis, a term that has primarily been used with other cancers, should be considered because overdiagnosis is also a major problem for colonoscopy screening."

We are taking our eyes off the ball.
The "great majority" of findings at colonoscopy are not cancers, but instead are small low-risk adenomas and nonadenomatous polyps, they emphasize. Current practice in the United States dictates that all polyps, regardless of size, be removed. This practice, which has "an uncertain net effect" on the patient, has led gastroenterologists astray, they note. "When our goal changes from reducing [colorectal cancer] mortality within reasonable levels of harms and costs to eradicating every existing polyp, we are taking our eyes off the ball," they write.

Cartoon image created by Dan Reynolds for the American Cancer Society