MORE complex, costly colon cancer test shows standard ones miss much

Wednesday, August 22nd 2001, 12:00 am

By: News On 6

Colonoscopy proved far superior to two other common tests for colon cancer in a study that could put pressure on more insurance companies to cover the expensive screening method.

Government researchers found that the two most widely used screening tests for colon cancer together missed one-quarter of the tumors and precancerous growths detected by colonoscopy.

Experts consider colonoscopy the ``gold standard'' test for the nation's No. 2 cancer killer, but they have been trying to establish with more certainty which method really is the best.

Medical guidelines generally call for annual testing for blood in a patient's stool and, every five years, a sigmoidoscopy, or examination of the lower colon, both starting at age 50. Some guidelines recommend colonoscopy as a routine test; others recommend it only for people who run a high risk of colon cancer, such as those with a family history of it, those who have had previous growths, or those who show signs of cancer during the stool test or a sigmoidoscopy.

The latest attempt to settle the uncertainty compared colonoscopy to a combination of sigmoidoscopy and the fecal blood test. The study, conducted by the Department of Veterans Affairs, backs the use of colonoscopy as a routine screening test.

``Colonoscopy currently is the best available test that we have,'' said Dr. David A. Lieberman, who led the study as chief of gastroenterology at the Portland Veterans Affairs Medical Center in Oregon. The study ``makes a case for at least considering colonoscopy as a screening test beginning at age 60.''

Colonoscopy involves the use of a flexible, lighted viewing tube that lets a doctor see the sedated patient's entire colon and immediately remove any growths. Costing at least $1,000, colonoscopy is about 95 percent accurate and is only needed every 10 years, starting around age 60 for people with no family history of colon cancer.

Sigmoidoscopy, which costs $100 to $200, uses a less-sophisticated viewing tube and cannot probe the colon's top two-thirds, where growths become more common, dangerous and hard to detect with age.

HMOs generally cover the use of colonoscopies for routine screening. Traditional fee-for-service insurance companies generally pay for them only for high-risk patients. Medicare began covering routine colonoscopies on July 1 but pays doctors only $300 for them. Private health insurers often follow Medicare's lead.

Colorectal cancer this year will kill an estimated 56,700 Americans and will diagnosed in 135,400 others, according to the American Cancer Society.

Lieberman and colleagues at 13 VA medical centers studied 2,885 veterans ages 50 to 75 who volunteered for a colonoscopy, a somewhat uncomfortable procedure. Results from the entire colon were compared with what was seen in just the lower one-third, the equivalent of a sigmoidoscopy, and with testing of patient stool samples for traces of blood.

The colonoscopy detected cancer in 24 patients and serious precancerous growths in 282 others. The fecal blood test was positive in only 24 percent of those cases, the ``sigmoidoscopy'' identified 70 percent of the tumors and growths, and the two combined identified 76 percent.

The research appears in Thursday's issue of the New England Journal of Medicine.

Dr. Sidney Winawer, head of the National Colonoscopy Screening Project and World Health Organization Center for the Prevention of Colorectal Cancer, said the study is excellent. But he said the question is whether people will be willing to undergo an invasive and expensive test every 10 years instead of a cheap and easy one each year. A fecal blood test costs just $10 to $25.

Only 30 percent of older Americans get an annual fecal blood test, he said.

Joe Luchok, spokesman for the Health Insurance Association of America, which represents nearly 300 health plans, said it is too soon to say whether this study will push companies to cover routine colonoscopies.

Robert A. Smith, director of cancer screening at the American Cancer Society, said it recommends colonoscopy as one of several testing options, because some patients cannot afford one or shy away from the test, which carries a slight risk of injury to the colon.

Also, Smith said, doing a colonoscopy requires special training many doctors have yet to receive.

Because 97 percent of the veterans tested were men, the researchers said more study is needed in women, who develop colon polyps and tumors several years later in life.