You probably saw the recent headline: Colonoscopy may not be as effective as previously thought at preventing colorectal cancer, which killed an estimated 50,000 people last year. But whether the procedure cuts the risk of getting and dying from colon cancer by 60 percent (as the study indicated) or 90 percent (as had been assumed), it's still the most effective screen for any common cancer, after the Pap smear. Unlike a mammogram or a test for prostate-specific antigen, colonoscopy can even be considered a form of prevention, since it enables the doctor to get rid of polyps before they become malignant. And yet fewer than half of people who should be screened—those ages 50 and older at average risk—are getting either a colonoscopy or one of the other highly recommended tests for colorectal cancer: sigmoidoscopy, CT or "virtual" colonoscopy, or a double-contrast barium enema.
The lesson from the new research is not that a colonoscopy isn't worth the yuck factor or the expense but that it's critical to make sure you get the best screening possible. That means choosing a doctor "who does a lot of them and does them well," says David Weinberg, a gastroenterologist who chairs the department of medicine at the Fox Chase Cancer Center in Philadelphia.
In addition to finding the best possible practitioner, you need to do your part beforehand. If your insides aren't as immaculate as you can get them, it's harder to detect polyps, especially the flat kind on the right side of the colon (which this study found to be a potential blind spot). There are variations on the prep, which is basically a clear-liquid diet for some period of time plus laxatives. Following to the letter whichever version your doctor recommends is the best way to ensure an unobscured view of the walls of your bowel, says Sidney Winawer, an attending gastroenterologist at Memorial Sloan-Kettering Cancer Center.
The colonoscopy isn't perfect; few medical procedures are. And no screening test can give you a 100 percent guarantee that you won't get colon cancer. (There are less invasive tests available, though they can't find precancerous polyps and have other drawbacks; the new stool DNA test requires you to mail in a bowel movement for testing.)
So besides adhering to the recommended screening schedule, you'll want to follow the usual prescriptions for a healthy life, since the evidence is mounting that they may fend off not just colon cancer but other chronic diseases as well: Eat a balanced diet heavy in fruits, veggies, and whole grains and light in saturated fat, and go lightly on the alcohol. Don't smoke (a recent study found that longtime smokers are more likely to get the disease). Get plenty of exercise, and keep your weight down.