Colonoscopy can save lives, but experts agree that testing rates remain too low. Now, researchers say a special scoring system might point to those people at highest risk for colon cancer, who may need the test the most.
The system might also make colon cancer screening more efficient and boost the number of people who get checked for the disease, said a team led by Dr. Thomas Imperiale of Indiana University Medical Center, in Indianapolis.
One expert said more efforts are needed to get people to undergo colonoscopy, which is currently recommended once every 10 years beginning at age 50.
“Five percent of the U.S. population will be diagnosed with colon cancer within their lifetimes,” said Dr. Arun Swaminath, director of the inflammatory bowel disease program at Lenox Hill Hospital in New York City. He was not involved in the new research.
Swaminath noted that one study published in 2012 found that “colonoscopy reduced the risk of death from colon cancer by 53 percent, by removing polyps. No other procedure is available to remove polyps from anywhere in the colon.”
And while some areas of the United States have rates of compliance with colonoscopy guidelines of 75 percent or more, “many areas have poor colon cancer screening rates,” he added.
Imperiale’s team noted that not all people deemed to be at “average risk” for colon cancer face the same risk of the disease, and so some might benefit more from invasive colonoscopy than others.
In the new study, the Indiana researchers looked at more than 4,400 Americans who were scheduled to undergo their first screening colonoscopy. They calculated a clinical “score” for each of these patients, based on their health information, and the five most common risk factors for colon cancer: age, sex, waist size, smoking and family history.
Then they looked at the results of each patient’s colonoscopy. The study found that patients classified under the scoring system as low-risk did, in fact, have far fewer advanced abnormal growths that might develop into cancer, compared to patients classified as high-risk.
So, patients scoring at the lower end of risk for colon cancer might be able to have less invasive screening tests (such as the fecal occult blood test), while those at higher risk would require a colonoscopy, Imperiale’s team concluded.
However, Swaminath wasn’t fully sold on the notion.
He believes that the scoring system “was only modestly able to separate people within the risk groups.” Swaminath pointed out that even the new study found that “low- to intermediate-risk patients still have a risk between of between 1.9 percent to 9.9 percent of harboring a polyp that can develop into cancer.”
For now, he said, the data from this study is not strong enough to spur any changes in current screening recommendations.
Dr. Jules Garbus is co-chief of colon and rectal surgery at Winthrop-University Hospital in Mineola, N.Y. He seemed more supportive of the new scoring system.
“A risk stratification tool is critical in helping physicians make appropriate screening recommendations for patients,” Garbus said. “While high-risk patients may ultimately require a screening colonoscopy, many average- and low-risk patients could undergo less invasive screening procedures. This can improve patient compliance with screening, as well as address escalating health care cost issues.
The study is published Aug. 10 in the Annals of Internal Medicine.
The U.S. National Cancer Institute has more about colorectal cancer screening.
SOURCES: Arun Swaminath, director, Inflammatory Bowel Disease Program, Lenox Hill Hospital, New York City; Jules Garbus, M.D, co-chief, colon and rectal surgery, Winthrop-University Hospital, Mineola, N.Y.; Annals of Internal Medicine, news release, Aug. 10, 2015
Last Updated: Aug 11, 2015
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This is an important story that touches on all sorts of issues involved in public health, including how to best to screen for a disease that takes a terrible toll, how to determine who is at highest risk and how to get the best use out of a test (colonoscopy) that is both expensive and invasive.
The story does a good job summarizing the study authors’ efforts to devise a scoring algorithm that might answer some of those questions, but makes only perfunctory references to cost and doesn’t acknowledge the long history of similar calculators that have been developed and never widely used. That’s pertinent context for this new effort. Despite leaving some room for improvement, the story makes a strong effort at interpreting a relatively simple algorithm with complex ramifications, and draws on two outside experts for perspective — something we wish more stories would take the time to do.
The concept of “risk stratification” — which is what this story and the related research paper address — is difficult for physicians and patients alike. Risk prediction tools are often created and then not used by physicians because they are cumbersome or their use historically has not been incorporated into guidelines because they have important limitations, including that even low-risk people still sometimes develop the cancer or condition. Since this new tool appears to suffer from these same limitations, it’s not clear if it will fare any differently than previous efforts, but the issue is worth exploring.
The question of cost is cited in the final line of the story, which suggests that the scoring system can “address escalating health care cost issues.” But we didn’t think that was specific enough to warrant a Satisfactory score. The story doesn’t clue readers in to the fact that the financial burden can be measured in billions of dollars — a single screening test recommended for millions of Americans can cost thousands of dollars apiece. The other cost issue specific to this test is that it takes valuable time for providers to retrieve a reputable risk calculator when sitting with a patient and enter in the specific data points, including in this case waist circumference, which clinicians often do not measure as a ‘vital sign’ per se.
The story cites a study that credits colonoscopy with reducing the risk of death from colon cancer by about 50 percent, by removing polyps. It would have been helpful for the story to explain what that relative reduction in risk means in absolute terms (e.g. did the rate of cancer death go from 50% to 25% or from 2% to around 1%?)
The story also notes that the study found that patients with a low to intermediate risk score “still have a risk between of between 1.9 percent to 9.9 percent of harboring a polyp that can develop into cancer.”
We’ll give credit here for the story’s provision of these key statistics, which do give a sense as how well the test accurately identifies truly low-risk individuals. However, we’d note that the benefit here should ideally refer to the ability of the algorithm to classify people at all risk levels (including high-risk), and therefore target the highest-risk patients for colonoscopy. The story doesn’t really get into discussion of the predictive power of the test, referred to as a likelihood ratio, which is in the study manuscript. However, this is a difficult concept for most health care providers and patients, and we think it’s understandable that the story did not include a full discussion of this topic.
The harm of a screening test such as this really is “getting it wrong” in terms of predicting someone to be at low risk and finding them to have a higher risk polyp or malignancy. As noted above, the story cautions that “low- to intermediate-risk patients still have a risk between of between 1.9 percent to 9.9 percent of harboring a polyp that can develop into cancer.”
This story accurately explains that the research was about predictive modeling, and explains the components of the risk score as well as the study design. There are some cautionary notes in the text, including a statement from outside expert that “the data from this study is not strong enough to spur any changes in current screening recommendations,” an opinion shared by an editorialist on the study. We think this is sufficient for a Satisfactory rating.
The story does not hype the incidence or seriousness of the disease. The prevalence statistics cited are consistent with these National Cancer Institute figures.
The story contains two independent voices. The perspective they provide is a particular strength of the article. We wish that more stories would reach out to experts not affiliated with the studies being reported on for context.
The story notes that a variety of screening tests exist, but the relevant alternative here is actually other risk calculators, which the authors of the study describe and cite but are not routinely used. The story doesn’t mention these other calculators and why they are seldom used — context that would have deepened reader understanding of the issue.
Although availability isn’t explicitly addressed, this risk calculator is now available (implicitly) by virtue of publication of the paper. It is a simple scoring system that can be implemented based on the information in the paper, and the story makes this clear. We’ll rate this Satisfactory.
The story makes it sound as if this is a first-of-its-kind tool. However, risk calculation tools for colon cancer have been in circulation for many years.
We could not find a news release related to this study. But in any case, the comments from two independent experts assure us that the story wasn’t based on a news release.