Colon Cancer Test Disappoints

Study: Fails To Detect Precancerous Growths In Two-Thirds Of Women

(AP) 
The researchers first used colonoscopes to find all polyps. They then calculated how many worrisome ones would have been missed by sigmoidoscopy alone.

Sigmoidoscopes were already in question because they find precancerous tumors in only 66 percent of average-risk men who have them. In this new study, sigmoidoscopes did even worse in average-risk women, detecting precancerous tumors in just 35 percent of the patients who had them.

Medical guidelines recommend either regular sigmoidoscopies or colonoscopies after age 50. The number of colonoscopies has already been rising in recent years, especially among high-risk patients. A federal survey put the number of colonoscopies at 14 million in 2002, compared to 3 million sigmoidoscopies.

Sigmoidoscopies are still performed for several reasons. A sigmoidoscopy is quicker, it is more convenient because it does not require the use of a sedative, and it costs far less than of a colonoscopy — perhaps $150 instead of $400 or more.

Also, many doctors had believed that the failure rate for sigmoidoscopies would be similar for both sexes.

A recent study by the Veterans Affairs Department found that demand for colonoscopies already outstrips availability. The researchers estimated that more than 30,000 additional doctors would be needed to screen people once every 10 years.

About 56,000 Americans are expected to die of colorectal cancer this year.