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Looking to the future, researchers would like to take advantage of some of Mother Nature's own ideas to design new chemotherapy drugs. Scientists at Vion Pharmaceuticals of New Haven, Conn., are interested in co-opting a group of Salmonella bacteria that normally attack the intestines and cause dysentery. Salmonella, it happens, also happily infect all kinds of tumors, including colon cancer. By loading genetically crippled salmonella with one of the body's own cancer-fighting chemicals (a molecule called tumor necrosis factor), researchers at Vion hope to destroy or at least shrink a wide variety of cancers. Safety studies in humans are planned for later this year.
Your best bet to beat colon cancer today is to catch it early--and that means regular screening. It would help if there were just one screening test and some simple rules to follow about when to get it done, but that's not the case. So pay attention to the following guidelines:
First, a warning. If you experience any symptoms--especially bleeding from the rectum, unusual constipation, abdominal cramping or a narrowing of the feces--talk to your doctor immediately about taking a peek inside your colon.
All other things being equal, you should start screening by age 50. (Some doctors lean toward 40, but more on that later.) If you have a family history of the disease, particularly among your siblings or parents, you may need to start in your 30s or 40s. A good rule of thumb is to begin getting tested 10 years before the youngest age at which colon cancer was diagnosed in any member of your family. "Don't wait for an invitation," says Dr. Bernard Levin of M.D. Anderson Cancer Center in Houston, Texas. "Tell your doctor, I want to get screened."
It's a good idea to keep track of other diseases that have affected your family. There's growing evidence that uterine and ovarian cancer may be genetically related to colon cancer. So if your Aunt Mary died of uterine cancer, don't assume you're in the clear if you've had a hysterectomy or if you're a man. You could be at greater risk of colon cancer as well. The same holds true if you suffer from inflammatory conditions of the intestines, like Crohn's disease or ulcerative colitis.
That's the "when" part of the equation. Now for what you should do. There are three different ways to get screened for colon cancer. Which method you choose depends a lot on your wallet--and the level of risk you're willing to live with.
If you go for the least expensive method--because it's the one most often covered by insurance--make sure you get both parts: a stool test, which looks for the presence of hidden blood, and a flexible sigmoidoscopy, in which a lighted tube is inserted into the lower third of the colon. The stool test should be repeated annually, since only 1 out of 3 tumors bleeds enough to be picked up by the test and then usually only after it's grown in size. The "flex sig" should be performed every five years, provided there's no change in symptoms or family history. Cost over five years: $100 to $200.
If you're not satisfied with checking out only part of your colon, you have two other options. Both require going on a liquid diet for 24 hours before the procedure and involve flushing the colon ahead of time. But they give more of the big picture.