ó A new test that requires people to send stool samples in
the mail for laboratory analysis is proving nearly as reliable
as a colonoscopy in identifying potentially fatal colon
screening test, invented at the Mayo Clinic, could become an
alternative to the colonoscopy ó or at least an option for
the millions of Americans who ignore their doctorsí
recommendations because they are squeamish about the rectal
exam or concerned about its cost, said Dr. David Ahlquist, a
Mayo gastroenterologist and co-inventor of the "Cologuard"
was 92 percent accurate at identifying patients with colon
cancer and 69 percent accurate at identifying patients with
the kinds of bowel lesions or polyps that indicate a high risk
for cancer, according to clinical trial results published
Wednesday in the New England Journal of Medicine.
will tell," Ahlquist said. "Itís our hope that
many individuals who are not being screened because of their
reticence to undergo colonoscopy will choose to undergo
screening with a noninvasive option like this."
screening for colon cancer is recommended at age 50 ó
earlier for people with family histories or greater risks ó
and was credited in a report Monday by the American Cancer
Society for a decline over the past decade in the U.S. rate of
colon cancer mortality.
lack of uptake is also why colon cancer remains the
third-leading cause of cancer mortality, and contributes to
50,000 deaths in the nation each year.
test comes with its own "eww!" factor, in that
people would need to fish out their own stool samples and
package them to send in for testing. But market research by
the test kit manufacturer, Exact Sciences of Madison, Wis.,
indicates that people arenít bothered as long as the test is
effective and covered by health insurance. Surveys showed only
3 percent of people being put off by having to collect a stool
kit comes in its own sturdy box Ö and the patient also uses
it to return the sample to the lab," said Exact Sciences
spokeswoman Cara Tucker. Test results would be sent to doctors
in about two weeks.
findings published Wednesday come from a company-funded
clinical trial of 10,023 people who were at normal risk for
colon cancer. They come about two weeks before a U.S. Food and
Drug Administration committee is scheduled to decide whether
the test is safe and effective for clinical use. In an unusual
step, the U.S. Centers for Medicare and Medicaid Services are
reviewing the test before the FDA review is complete ó an
indication that the federal agency might expedite Medicare
coverage of the test for the nationís elderly population.
approval could mean the Cologuard test would be available as
early as midsummer.
study was a head-to-head comparison with an existing test
called FIT, which detects cancer by finding hidden blood in
stools, and showed that the new DNA screening found more
cancers and cancer risks.
works because tumors and polyps in the colon "shed"
cells that are detectable in human waste, Ahlquist explained.
However, the DNA test resulted in some false positives ó
about one in 10 tests suggested patients had colon cancer or
an imminent risk for it, when they didnít.
clinical care, patients with positive results from Cologuard
would undergo colonoscopies to confirm the results, said Dr.
Thomas Imperiale, an Indiana gastroenterologist who was lead
author of the study.
positives do cause stress and anxiety, he said, but in the end
they would direct patients to receive colonoscopies that they
would have likely received anyway if the DNA test didnít
of false negatives was low, and would likely be overcome if
patients repeated the test over time, he said. Whether the
test would be recommended annually, or less frequently, is
unclear. The cost remains unclear as well, though it would
presumably be cheaper than a colonoscopy that requires a visit
to a specialty clinic or hospital.
Cathleen Clouse, a HealthEast family practice doctor in
Maplewood, Minn., said she would welcome a new alternative for
the many patients who are uneasy about colonoscopies or
dislike the voluminous fluids they must consume in advance to
clean out their bowels.
her patients were referred to specialty clinics for
colonoscopies and suffered the rare complication of having
their bowels perforated.
the alternative, I think people are going to choose the DNA
test," she said. "Youíd be surprised what people
are willing to do because they donít want the colonoscopy."