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Lopsided Colonoscopies

January 7, 2009

Colonoscopies are very effective at detecting tumors in the left colon but nearly useless in detecting tumors in the right.


BOB HIRS HON (host):
A test that’s only right about the left. I’m Bob Hirshon and this is Science Update.

Doctors recommend routine colonoscopies for people over 50. But new evidence suggests these tests’ high success rate is literally one-sided. University of Toronto colorectal surgeon Nancy Baxter and her colleagues compared the medical records of ten thousand people who died from colon cancer, to matched controls who didn’t. They estimated that colonoscopies prevented two-thirds of potential deaths from cancers on the left side, or lower end, of the colon.

NANCY BAXTER (University of Toronto):
So it’s highly effective for that, but didn’t really seem to be effective at all in preventing right-sided colon cancer.

She says flatter tumors in the right colon and a more obstructed view of them may be to blame. She stresses that colonoscopies are still very useful, but that doctors should be aware of their limitations. I’m Bob Hirshon for AAAS, the Science Society.