A
Low-Tech Way to Find Colon Cancer: Home Screening Tests Get More Reliable.
A simple home-screening test for colon cancer, long derided as ineffective,
is making a comeback.
A slew of new
fecal occult blood tests, or FOBTs, have hit the market in recent months,
incorporating improved technology that does a far better job of finding cancer
and potentially cancerous polyps than the older version of the test. An editorial
in the influential medical journal Gastroenterology this month calls
for increased use of the new FOBTs, which, like the older version, test stool
samples for blood or its components, an early sign of colon cancer.
Convincing consumers
to use the tests may be tough, however. Recent publicity encouraging people
to seek colon-cancer screening, particularly colonoscopy, has left many patients
with the wrong impression that other tests aren't useful, doctors say. In
addition, there's the "ick factor" of fecal tests, which typically
require patients to smear stool on a card that is then sent to a lab.
But there is
growing evidence that the $20 to $40 tests can be a powerful tool in battling
colon cancer, which kills 58,000 Americans a year, making it the second-biggest
cancer killer after lung cancer. Colon cancer often doesn't produce symptoms
until it is well advanced. Screening tests can find it sooner and improve
your chances of survival.
The most-talked-about
method is colonoscopy, which gained widespread attention when NBC newswoman
Katie Couric began promoting colonoscopy screening after her husband, Jay
Monahan, died of colon cancer. But colonoscopy, which uses a scope to view
the colon while the patient is sedated, is expensive. And the procedure requires
bowel-cleansing medications that force patients to spend a day close to a
toilet.
The bigger issue
is that there simply aren't enough doctors to perform colonoscopies on everybody
50 and older, as is typically recommended. The Baylor College of Medicine
system in Houston said it would take 30 years to perform screening colonoscopies
on all of its eligible patients, according to a 2001 letter to the New England
Journal of Medicine from a Baylor physician.
The U.S. Preventive
Services Task Force, which sets screening guidelines, recommends colonoscopy
and FOBT, as well as two other options: X-ray with a barium enema and sigmoidoscopy,
which scopes a small portion of the colon. The task force doesn't endorse
any one test as better than the others.
"Everywhere
you go, people are afraid to have anything but colonoscopy," says James
Allison, the University of California-San Francisco professor who wrote the
Gastroenterology editorial and is also a consultant for fecal-test maker Enterix.
"These other tests are also good for screening with colon cancer -- they
shouldn't be dismissed."
Just last week,
Beckman Coulter of Fullerton, Calif., which makes the most widely used FOBT,
launched the Hemoccult ICT, which uses the improved technology. FOBTs are
the simplest and least-invasive test. But many patients and even doctors don't
use the tests correctly, performing an FOBT just once or infrequently.
Fecal tests
should be used annually. That's because polyps and cancer may bleed only intermittently,
so any one stool sample may not contain blood. Studies show frequency of use
can make a dramatic difference. More than a decade ago, a major U.S. study
showed that among patients who used FOBTs annually, the risk of dying from
colon cancer dropped by 33%. Two separate European studies showed that patients
who used the tests every other year had just a 15% lower risk of dying.
[Cancer Screening]
But in January,
the Annals of Internal Medicine reported that both patients and doctors are
widely misusing FOBTs. In the study, nearly one-third of doctors gave a repeat
FOBT when the test was positive -- but screening guidelines say a positive
test should always result in a colonoscopy.
Another problem:
nearly one-third of doctors studied used in-office FOBTs, in which doctors
remove stool from the rectum for testing. Such testing of a single stool sample
is virtually useless. Home testing typically involves collecting two samples
from each of three consecutive bowel movements. One recent study showed that
the office version detects just 5% of cancers, compared with 24% for the home
test kit.
A new version
of home testing, called fecal immunochemical tests, or FIT, does an even better
job of finding cancer. This month the journal Gastroenterology reported that
a Japanese study of FIT found 65% of cancers and 20% of large polyps. Old-style
FOBTs find 13% to 39% of cancers. The detection rate would go far higher if
the FIT test is performed consistently over several years.
Last year, Medicare
increased its reimbursement rates for the new tests. Still, many doctors haven't
focused on recommending them. And patients are often put off by fecal testing.
One newer FIT test -- Insure from Enterix, of Edison, N.J. -- uses a paint
brush that is swept over the stool in the toilet, but others still require
a sample of stool.
"It is
a little gross, but grow up, it could save your life," says gastroenterologist
Mark Pochapin, director of the Jay Monahan Center for Gastrointestinal Health
in Manhattan.
And many patients
aren't undergoing any screening at all. A study this month in the journal
Cancer, found that over a five-year period, almost half of nearly 22,000 primary-care
patients didn't receive any of the screening options, says study author Jennifer
Elston Lafata, research scientist at the Henry Ford Hospital in Detroit.
The newer "virtual"
colonoscopy is gaining in popularity, but it isn't yet recommended by the
Preventive Services Task Force.
Indiana University
professor Thomas Imperiale, who has also conducted studies for test makers,
says one problem is that doctors don't take the time to discuss all the options
with patients. "The best test is the one the patient will do," he
says.
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