TAMPA, FLA. - A new test using computerized imaging instead of
an invasive probe may soon be available to detect colorectal cancer, doctors
announced Monday at a seminar sponsored by the American Cancer Society. A few
American medical centres are studying this screening method known as virtual
colonoscopy. It uses high-speed computerized tomography (CT) scan machines to
produce a three-dimensional image of the colon. Studies suggest it may
accurately detect cancerous lesions about 80 per cent of the time.
Colorectal cancer is a very common type of cancer for both men and
women. It is the third most common form of cancer in Canada next to lung and
breast cancer. Approximately 16,000 Canadians are diagnosed with colorectal
cancer each year.
In the U.S., an estimated 130,000 Americans a year are
affected. Half of that number die from the disease.
Half of these
deaths, doctors say, could be prevented with proper screening and removal of
precancerous tumors. They suggest anyone over age 50 and younger patients with a
family history of the disease should be tested.
Scientists say only half
of people aged 50 or older are screened regularly. More than 90 per cent of
colorectal cancers occur after age 50.
Research shows people avoid
screening because they are often embarrassed, afraid or do not want to have
invasive tests.
There are four screening methods currently available:
first, tests done in doctors' offices that look for blood in stool; second, a
procedure involving insertion of a flexible scope looks at the last part of the
colon; third, barium enemas combined with X-rays; and fourth, full colonoscopies
in which the organ is more extensively probed with a scope.
In virtual
colonoscopy, the bowel must still be cleaned using laxatives and enemas. Like
the scope procedures, gas is introduced through a tube to expand the area for
proper viewing. But after that, patients lie on a table for a five-second scan.
The new test is also less expensive than the traditional colonoscopy.
According to researchers, the latter can range from $1,800 U.S. to $2,000 U.S.
In comparison, virtual colonoscopy can cost about $400 U.S.
This
technology is currently used on patients taking part in research. Scientists
hope it will become a widespread tool for detecting this type of cancer.
