Colonoscopy Crowned Best for Detecting Colon Cancer
Because colonoscopy is expensive -- about $1,000 -- and requires that
patients be given anesthesia, some experts have suggested that it should be
reserved for those patients who have polyps detected using the far less
expensive flexible sigmoidoscope. But Imperiale says that strategy would miss
nearly half of the polyps that could lead to cancer, as he found in his study.
Having said that, Imperiale, who is an assistant professor of medicine at
Indiana University School of Medicine in Indianapolis, says he doesn't favor
colonoscopy for everyone.
"My take is that there should be a more balanced approach. I do think we
need to be more liberal in the use of colonoscopy, but our long-term goals
should be to find ways to estimate risk more accurately," Imperiale says.
He says that abandoning flexible sigmoidoscopy in favor of colonoscopy is
"going to the other extreme ... remember, the vast majority of patients in
our study and other studies had no polyps." Imperiale says he differs from
many of his colleagues in that he takes a conservative approach to colonoscopy.
"We don't have high enough numbers to say with great confidence who does
and who doesn't need colonoscopy," he says.
Douglas Rex, MD, is one of the authors of the American College of
Gastroenterology's current screening guidelines. Those guidelines recommend a
first colonoscopy at age 50 for those with average risk and a follow-up
colonoscopy every 10 years thereafter. Rex tells WebMD that "Imperiale
tends to be very cautious. There is a significant jump in colon cancer
beginning at age 50 and continuing through age 60, and then it levels off with
age." Rex is a professor of medicine at Indiana University and is a partner
in the same practice as Imperiale.
David A. Johnson, MD, also a co-author of the guidelines, says he too thinks
both studies make the case for colonoscopy.
Johnson, a professor of medicine at Eastern Virginia Medical School in
Norfolk, says, "Colonoscopy is the best evolving screening modality that we
have, and it should be utilized without waiting for symptoms." He says that
for some reason -- possibly a change in diet or other environmental factor --
colon cancers have moved from their historic location low in the rectum to
higher in the colon.
He adds that screening tools have also evolved from the rigid sigmoidoscope,
which was adequate in the 1930s, to the use of flexible sigmoidoscopy. "But
with this tremendous shift in position, even with the flex sig you can't get in
there. That's why in the last several years, there has been a recognition of
the need for whole colon imaging."
Johnson says the American College of Gastroenterology is so pro-colonoscopy
that it has decided to launch an effort in "10 to 15 key states, including
New York, to introduce model legislation that will require health insurance
companies to cover screening colonoscopy." He says that Virginia already
has such a bill, which was introduced by state Sen. Emily Couric, sister of TV
personality Katie Couric, whose husband died as a result of colon cancer. He
says the state campaigns will begin in full force this fall.