Colonoscopy Crowned Best for Detecting Colon Cancer
WebMD News Archive
The second study in the journal attempted to determine whether the presence
of polyps in the lower area of the colon is a marker for cancers higher in the
colon. The researchers thought that if a lower polyp predicts the presence of a
cancer higher up, then flexible sigmoidoscopy may be an adequate screening
tool. The scientists analyzed almost 2,000 patients with no symptoms over the
age of 50 who underwent initial colonoscopy. Twelve cancers -- eight in men --
were detected by the screening.
The scientists found that the presence of a polyp in the lower colon
does increase the likelihood that the person has a colon cancer farther
up. However, one of the study's authors, Thomas F. Imperiale, MD, tells WebMD
that more than half of the people with cancer high in the colon -- beyond the
range of the flexible sigmoidoscope -- had no polyps close to the rectum.
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.