A simple home-screening test for colon cancer, long derided as ineffective, is making a comeback.

A slew of new fecal occult blood tests, or FOBTs, have hit the market in recent months, incorporating improved technology that does a far better job of finding cancer and potentially cancerous polyps than the older version of the test. An editorial in the influential medical journal Gastroenterology this month calls for increased use of the new FOBTs, which, like the older version, test stool samples for blood or its components, an early sign of colon cancer.

Convincing consumers to use the tests may be tough, however. Recent publicity encouraging people to seek colon-cancer screening, particularly colonoscopy, has left many patients with the wrong impression that other tests aren't useful, doctors say. In addition, there's the "ick factor" of fecal tests, which typically require patients to smear stool on a card that is then sent to a lab.

But there is growing evidence that the $20 to $40 tests can be a powerful tool in battling colon cancer, which kills 58,000 Americans a year, making it the second-biggest cancer killer after lung cancer. Colon cancer often doesn't produce symptoms until it is well advanced. Screening tests can find it sooner and improve your chances of survival.

The most-talked-about method is colonoscopy, which gained widespread attention when NBC newswoman Katie Couric began promoting colonoscopy screening after her husband, Jay Monahan, died of colon cancer. But colonoscopy, which uses a scope to view the colon while the patient is sedated, is expensive. And the procedure requires bowel-cleansing medications that force patients to spend a day close to a toilet.

The bigger issue is that there simply aren't enough doctors to perform colonoscopies on everybody 50 and older, as is typically recommended. The Baylor College of Medicine system in Houston said it would take 30 years to perform screening colonoscopies on all of its eligible patients, according to a 2001 letter to the New England Journal of Medicine from a Baylor physician.

The U.S. Preventive Services Task Force, which sets screening guidelines, recommends colonoscopy and FOBT, as well as two other options: X-ray with a barium enema and sigmoidoscopy, which scopes a small portion of the colon. The task force doesn't endorse any one test as better than the others.

"Everywhere you go, people are afraid to have anything but colonoscopy," says James Allison, the University of California-San Francisco professor who wrote the Gastroenterology editorial and is also a consultant for fecal-test maker Enterix. "These other tests are also good for screening with colon cancer -- they shouldn't be dismissed."

Just last week, Beckman Coulter of Fullerton, Calif., which makes the most widely used FOBT, launched the Hemoccult ICT, which uses the improved technology. FOBTs are the simplest and least-invasive test. But many patients and even doctors don't use the tests correctly, performing an FOBT just once or infrequently.

Fecal tests should be used annually. That's because polyps and cancer may bleed only intermittently, so any one stool sample may not contain blood. Studies show frequency of use can make a dramatic difference. More than a decade ago, a major U.S. study showed that among patients who used FOBTs annually, the risk of dying from colon cancer dropped by 33 percent. Two separate European studies showed that patients who used the tests every other year had just a 15 percent lower risk of dying.

But in January, the Annals of Internal Medicine reported that both patients and doctors are widely misusing FOBTs. In the study, nearly one-third of doctors gave a repeat FOBT when the test was positive -- but screening guidelines say a positive test should always result in a colonoscopy.

Another problem: nearly one-third of doctors studied used in-office FOBTs, in which doctors remove stool from the rectum for testing. Such testing of a single stool sample is virtually useless. Home testing typically involves collecting two samples from each of three consecutive bowel movements. One recent study showed that the office version detects just 5 percent of cancers, compared with 24 percent for the home test kit.

A new version of home testing, called fecal immunochemical tests, or FIT, does an even better job of finding cancer. This month the journal Gastroenterology reported that a Japanese study of FIT found 65 percent of cancers and 20 percent of large polyps. Old-style FOBTs find 13 percent to 39 percent of cancers. The detection rate would go far higher if the FIT test is performed consistently over several years.

Last year, Medicare increased its reimbursement rates for the new tests. Still, many doctors haven't focused on recommending them. And patients are often put off by fecal testing. One newer FIT test -- Insure from Enterix, of Edison, N.J. -- uses a paint brush that is swept over the stool in the toilet, but others still require a sample of stool.

"It is a little gross, but grow up, it could save your life," says gastroenterologist Mark Pochapin, director of the Jay Monahan Center for Gastrointestinal Health in Manhattan.

And many patients aren't undergoing any screening at all. A study this month in the journal Cancer, found that over a five-year period, almost half of nearly 22,000 primary-care patients didn't receive any of the screening options, says study author Jennifer Elston Lafata, research scientist at the Henry Ford Hospital in Detroit.

The newer "virtual" colonoscopy is gaining in popularity, but it isn't yet recommended by the Preventive Services Task Force.

Indiana University professor Thomas Imperiale, who has also conducted studies for test makers, says one problem is that doctors don't take the time to discuss all the options with patients. "The best test is the one the patient will do," he says.