WEDNESDAY, Dec. 5 (HealthDay News) -- If colon cancer screening
was as easy as taking a breath, more people might do it. Now, a
small pilot study suggests such a test could be developed.
The study, of 78 people with and without colon cancer, found
that those with the disease tended to have a distinct pattern of
chemicals in their breath. And when researchers analyzed the study
participants' breath samples, they correctly identified the colon
cancer patients 76 percent of the time.
The findings, reported online Dec. 5 in the
British Journal of Surgery, sound good. But if you're
waiting for your doctor to offer such a test, don't hold your
"It's an interesting concept, but this is in the very early stages," said Dr. Durado Brooks, director of prostate and colorectal cancers for the American Cancer Society.
"There's no way to tell if this would work in the general population," said Brooks, who was not involved in the research.
What's more, he added, there are already several good ways to
catch colon cancer -- or, even better, precancerous growths called
polyps, which can then be removed before a tumor develops. Yet
about 40 percent of Americans who should be getting screened are
"Colon cancer is a highly preventable disease," Brooks said. "And I would encourage the four out of 10 people who are not taking advantage of the existing screening tools to talk with their doctor."
The idea of using a breath test to catch cancer is not new:
Researchers are looking into breath tests for detecting a number of
cancers, including lung and breast tumors. It's all based on
studies showing that breath samples from cancer patients tend to
have a distinguishing pattern of so-called volatile organic
When it comes to colon cancer, people already have several
options for screening, which for most adults should begin at age 50
-- or possibly earlier if you are at higher-than-normal risk.
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
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
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 more questions than answers."
Learn more about colon cancer from the
U.S. National Cancer Institute.