WEDNESDAY, March 12, 2003 (HealthDayNews) -- Colorectal cancer is the second-leading cancer killer in the United States, claiming more than 57,000 lives every year.
Yet, the vast majority of these deaths could be prevented.
How? Through regular screening by a medical professional.
Because March is National Colorectal Cancer Awareness Month, 50 organizations have joined forces to spread the message that screening measures -- plus a healthy lifestyle -- can help stop this killer in its tracks.
"People are great procrastinators, [but] a screening test will help save your life," says Dr. Sidney Winawer, co-chairman of the International Digestive Cancer Alliance and a professor of medicine at Memorial Sloan-Kettering Cancer Center in New York City.
While lifestyle is important -- specifically, regular exercise combined with a balanced, healthy diet that includes plenty of fruits and vegetables and fewer animal fats -- screening is the proven key to prevention.
Virtually all colorectal cancers start as polyps, or abnormal growths, so the key is to find the polyps before they turn malignant.
"The National Polyp Study, an Italian study and a University of Minnesota study have shown that removing polyps prevents colon cancer," Winawer says.
When it comes to spotting potentially dangerous polyps, the technique of choice is the colonoscopy, although other promising tools are under review. And Medicare now pays for colonoscopies, an indication of just how seriously the medical establishment is taking the issue of prevention and early diagnosis of colorectal cancer.
New guidelines issued in February by the U.S. Multisociety Task Force on Colorectal Cancer state that all men and women over age 50 who have no symptoms and no family history of colorectal cancer should have a colonoscopy. People with a family history need to be screened starting at an earlier age.
The procedure, which usually takes half an hour and is done under mild sedation, involves the insertion of a long, flexible tube with a camera mounted on the end up through the rectum and on into the colon, or large intestine. The camera takes pictures and transmits them outside the body.
Perhaps the best thing about a colonoscopy is that it's "one-stop shopping," says Winawer, lead author of the new guidelines.
"You can do screening, diagnosis and treatment by removing the polyps all in one examination," he adds.
The downside of the procedure is the preparation, which involves taking potent laxatives to make sure the colon is completely clear.
"The preparation is not pleasant, but I think it's a small price to pay for one's life," Winawer says.
In the future, patients may benefit from a "virtual colonoscopy," the procedure newswoman Katie Couric underwent on the NBC "Today" show last March. Less invasive than a conventional colonoscopy, a virtual colonoscopy uses a computer assisted tomography (CAT) scanner to survey the colon from outside the body.
However, a virtual colonoscopy requires the same preparation as a conventional colonoscopy, is not able to perform biopsies or remove polyps, and may or may not be as effective as the traditional treatment.
"It's potentially promising, but we don't know how accurate it is yet," Winawer says.
Another promising screening method under investigation is DNA testing that hunts for genetic mutations in stool samples that might indicate the presence of cancer or precancerous growths.
"Right now, the pick-up rate [for spotting cancerous polyps] is about 50 percent and it's a very complex laboratory assay that's required," Winawer says. "It's not generally available nor is it approved for general screening use."
Taking a chapter from Fantastic Voyage, researchers have also developed a tiny capsule containing a camera. The capsule is swallowed as if it were a regular pill, then the camera takes pictures as it travels through the digestive tract. The video transmittals are relayed to doctors viewing a computer monitor on the outside. The procedure is only FDA-approved for the small intestine, which is located above the large intestine.
"It works well for the small bowel [small intestine], but it doesn't work well for the colon [large intestine]," says Dr. David Beck, chairman of the department of colon and rectal surgery at the Ochsner Clinic Foundation in New Orleans. "It's not as good a picture of the colon as the scope."
Again, the miniature camera would not be able to perform a biopsy or remove a troublesome growth.
"You'd have to go back in, but that may be a way to see who really needs a colonoscopy," says Dr. Michael Bouvet, a surgical oncologist at the Rebecca and John Moores University of California San Diego Cancer Center. "These are all not ready for prime time."
There have also been advances even when screening does detect cancer.
Surgery to remove cancerous portions of the colon or rectum is still the primary treatment. "If the cancer is caught early, it's very curable," Beck says. "If the tumor is more advanced, we may add some additional things like radiation or chemotherapy."
If a tumor is found in the rectum, physicians will often do chemotherapy to shrink the tumor before surgically removing it. This is in an effort to preserve the sphincter at the entrance of the rectum so the patient can continue with normal bowel movements, Bouvet says.
"The big message really is: Please don't wait for something like this down the road," Winawer says. "Save your life today by going in for a screening test that's available today."
More information
Visit the Cancer Research and Prevention Foundation for more on National Colorectal Cancer Awareness Month.
To learn more about colorectal cancer, visit the U.S. Centers for Disease
Control and Prevention, the National Cancer Institute or the American Cancer Society.
