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In a double-contrast barium enema, a technician coats the inside of the intestine with the metallic dye and pumps the colon full of air. Then an X ray of the large intestine is taken, allowing doctors to visualize the outline of most abnormal growths. Provided the colon is clear, a barium enema should be repeated every five to 10 years. Cost: $200 to $400.
The other option is a colonoscopy, the procedure Couric underwent for the Today show. At $1,000 or more a pop, it's both expensive and invasive. Under normal circumstances you have to do it only once a decade.
"The prep is a pain," Couric admits. The colonoscopy itself is conducted under a mild sedative. "I was chatting the whole time," Couric recalls, "bossing my camera crew around." There is a risk, albeit a small one, that the device can slip and punch a hole in the intestinal wall. Yet a colonoscopy offers a distinct advantage in that the doctor can remove any small precancerous polyps as soon as they are found, making it the only screening test that can prevent cancer, not just detect it.
That is why some doctors and quite a few activists are lobbying to make colonoscopy the test of choice. They point to small studies of people with a genetic predisposition to colon cancer that show that snipping out polyps on a regular basis decreases chances of developing the disease. Dr. Sidney Winawer of Memorial Sloan-Kettering Cancer Center in New York City is directing a larger study to see if that holds true for the general population.
Until then you could be stuck in a classic medical Catch-22. Most insurance companies won't pay for a colonoscopy unless you have a family history or symptoms. But if you already have symptoms, any tumors the test uncovers are likely to be advanced. The insurance industry insists it is just following procedures. "There isn't enough evidence [on whether colonoscopy screening saves lives] to recommend for or against it," says Dr. Charles Cutler, chief medical officer of the American Association of Health Plans. For years Senator Edward Kennedy of Massachusetts has pushed a bill that would mandate reimbursement for all screening exams. It is still languishing in Congress.
Executives at pharmaceutical giant Eli Lilly aren't waiting for government action. They offer free colonoscopies to all their employees starting at age 40. "The guidelines typically suggest screening at age 50, because that's when the incidence of colon cancer becomes statistically significant," says Dr. Gregory Larkin, director of corporate health services for Lilly. But since it takes precancerous polyps five to eight years to develop, he notes, why wait a decade to start removing them?
Still not ready to sign up for a colon exam? Researchers are trying to perfect the so-called virtual colonoscopy, which doesn't require threading any medical instruments into the colon. Instead, doctors rely on cat-scan imaging to create a computer-generated 3-D picture of the inside of the intestine. It's still not clear, however, how accurate the new technology is. So don't put off getting the tests that are available today in hopes of taking a less invasive one later.