TUESDAY, June 3, 2014 (HealthDay News) -- Colonoscopies in certain elderly people who've never been screened could be a cost-effective way to improve their health while extending their lives a bit.
The study findings, which rely on statistical projections, aren't definitive. Still, the research suggests that "colorectal cancer screening should be considered well beyond age 75 in the elderly without previous screening," said study lead author Frank van Hees. He is a scientific researcher with the department of public health at Erasmus University Medical Center in Rotterdam, the Netherlands.
At issue are three kinds of tests: colonoscopy; a similar test called a sigmoidoscopy; and fecal immunochemical tests in which fecal samples are tested by a laboratory for signs of blood in the stool. Only colonoscopies allow physicians to remove potentially dangerous polyps during the procedure. If signs of trouble are found in the other tests, a follow-up colonoscopy is required.
"It is a common misconception that guidelines recommend against colorectal cancer screening in all individuals aged over 75," van Hees said. In fact, guidelines in the United States only recommend against routine screening in people aged 75 and older if they've already had regular negative screenings from age 50 onward, according to background information in the study.
"None of the current guidelines addresses the appropriateness of screening in those aged over 75 without previous screening," van Hees said. Estimates suggest that there are 4 million people in the United States who fall into that category, he noted.
In the new study, van Hees and colleagues used statistical analysis to determine the risks of colorectal cancer for various simulated groups of older people aged 76 to 90. Then they projected what would happen if the simulated groups underwent different types of screening tests.
"This is a method that has been used to examine questions about tests we offer to a population when we don't have the actual data available," explained Dr. David Carr-Locke, chief of the division of digestive diseases at Beth Israel Medical Center in New York City, who's familiar with the study. "You create a model, assume a lot of things, and let it run. It's never a real study of real people."
The findings suggest that screenings for cancer continue to be worthwhile and cost-effective up until age 86 in previously unscreened people without major health problems, including colonoscopies until age 83, sigmoidoscopies up until age 84, and the fecal tests up until age 85 or 86.
As for lifespans, "in healthy individuals aged 76 without previous screening, a screening colonoscopy prolongs life by an average of 36 days," van Hees said. "This effect declines to 26 days at age 80, 13 days at age 85, and only 5 days at age 90. In individuals with a less favorable life expectancy, the benefits of screening are substantially smaller."
The researchers adjusted their statistics to take into account the higher risks of side effects of colonoscopies. And, van Hess said, they tried to account for the unpleasant nature of colonoscopies by assuming "a loss of quality of life equivalent to two full days of life for each colonoscopy performed. We did not assume this burden to increase with age."
Carr-Locke praised the study and said it's appropriate to screen older people for colorectal cancer, especially when they're healthy. "There are a lot of people in their 80s who are very fit and healthy and request screening. We go ahead and do it," he said.
The study is published in the June 3 issue of Annals of Internal Medicine.
For more about colonoscopies, visit the American Cancer Society.