The choices include a yearly stool test that looks for hidden blood, or either of two invasive tests that scope the colon: sigmoidoscopy every five years, along with stool testing every three years; or colonoscopy every 10 years.
But many people are turned off by those tests.
So Dr. Donato Altomare and colleagues at the University Aldo Moro in Bari, Italy, decided to test the feasibility of a breath test.
Analyzing breath samples from 37 patients with colon cancer and 41 healthy middle-aged adults, the researchers found 15 VOCs that seemed to differ between the two groups.
They then used a statistical model to see if certain VOC patterns separated the colon cancer patients from the healthy participants. In the end, the researchers were able to correctly identify the cancer patients 76 percent of the time.
But, Brooks pointed out, that also means the breath test was wrong about one-quarter of the time.
There's no way of knowing how well such a screening test would work in the real world -- including how many people might wrongly get a positive result and undergo needless invasive tests to follow up, Brooks said.
Another big question, he added, is whether breath analysis could pinpoint people with colon polyps.
"One of our goals in screening is to detect polyps, not cancer," Brooks said. "This study doesn't address that."
Altomare's team acknowledges that there is a lot of work left to do. It's still unclear which breath chemicals should be measured, or what statistical method is best for weeding out cases of colon cancer.
Brooks said it would be nice to have a very simple, accurate screening test -- whether that means a breath test or blood or urine tests. Yearly stool tests are simple and cheap, but people often don't want to do them.
"We're always searching for simpler things to do," Brooks said. But for now, he added, "this study raises many
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