LEE'S SUMMIT, Mo. -- Colorectal cancer will kill 50,000 Americans this year. One reason is that about half of people over age 50 don't get screened as recommended. The cancer is found too late. But that could change with a new, noninvasive test.
Cologuard is a DNA test of a small sample from the stool. No bowel preparation or diet changes are required. A new study in the New England Journal of Medicine found Cologuard was 92 percent effective in detecting colorectal cancer, and 69 percent effective in detecting polyps most likely to become cancerous.
"Ninety-two percent is excellent, and you have to understand that colonoscopies are not 100 percent accurate," said Dr. Marc Taormina of Midwest Gastroenterology.
Dr. Taormina says Cologuard appears on par with colonoscopy's effectiveness. And in this study, Cologuard was much more effective than a stool test that checks for human blood.
But many questions remain. If the DNA test shows no signs of cancer, can you skip colonoscopy? What about false positive results? In the study, about 10 percent of patients had a positive test, but a follow-up found no cancer. Dr. Taormina says more testing of other parts of the GI tract might then be ordered to rule out cancer.
"That may elevate the cost of the evaluation in the long-term," said the gastroenterologist.
Follow-up testing can also increase anxiety for patients.
The new test is not yet FDA-approved, but a committee is set to review it this month.