Colorectal Cancer

Colorectal Cancer

More Detectable--
And Curable--Than Ever

It's no fun. For a fecal occult exam, a gynecologist slides a gloved finger into your rectum, scoops out a stool sample and smears it on a slide to check for hidden blood.

But even though it's not enjoyable, many gynecologists across the country take the time to do this simple test during a pelvic exam. Early detection methods can help save lives. In fact, because of exams like this one, as well as other factors, deaths due to colon and rectal cancer--collectively known as colorectal cancer--are down 30 percent in women over the past 30 years.

Approximately 74,000 women will develop colorectal cancer this year, making it the second most common cancer in women. Twenty-eight thousand will die. But there are a number of things you can do to help reduce your risk.

Diet and Genetics

Although scientists still haven't figured out exactly what causes colorectal cancer, they have figured out what puts us at risk: "Ninety percent of colorectal cancer is diet-related, while 10 percent occurs in people with a clear-cut genetic predisposition," says Elin Sigurdson, M.D., Ph.D., a surgical oncologist at the Fox Chase Cancer Center in suburban Philadelphia and a researcher on the center's cancer prevention team.

Scientists suspect that diet and genetics may--separately or together--damage cells in a way that sets off the growth of small polyps along the intestinal tract.

Although not all polyps evolve into tumors, all tumors evolve from polyps, says Dr. Sigurdson. So anything that encourages their growth puts a person at risk for cancer.

Some people carry a family gene that triggers polyp formation, while others seem to experience their growth after exposure to free radicals--molecular fragments that are generated by everyone during the body's normal metabolism of dietary substances such as fat.

The theory is that in the colon, these molecular fragments damage genes that control cellular growth, says Dr. Sigurdson. Eventually, a cell's genes can receive so much damage that they no longer function normally, and the uncontrolled cellular growth that becomes cancer can begin.

That's why people who eat a lot of fat, a substance that releases free radicals, may also be at increased risk. A study of 375 women and 270 men at the University of North Carolina at Chapel Hill found that women who ate more than 77 grams of fat per day were more than twice as likely to develop precancerous polyps as those who ate less than 58 grams per day. What's more, a study of more than 88,000 women at Harvard Medical School revealed that women who ate beef, pork or lamb--all high in fat--every day were more than twice as likely to develop colon cancer as those who didn't.

Protect Yourself

Blood in a bowel movement is usually what sends most of us skittering to the doctor. And while it doesn't mean you have colorectal cancer, it is one of the earliest symptoms. Once colorectal cancer strikes, however, early detection can mean the difference between life and death, experts agree.

Ninety-two percent of those who have colon cancer surgically removed while it is still located in a single spot will still be alive five years from diagnosis, making this one of the more survivable cancers, reports the American Cancer Society.

Delayed treatment for rectal cancer has the same result. Eighty-five percent of those who have rectal cancer removed while it is still localized will still be alive five years from diagnosis. Only 51 percent of those who wait for treatment until the cancer spreads will be.

The only way to completely assure survival from colorectal cancer is to prevent it, says Dr. Sigurdson. And here are some ways.

Cut your fat consumption in half. Over the years researchers have noticed that there's a distinct correlation between the amount of colorectal cancer in a country and the amount of fat in the diet of its people, says Dr. Sigurdson. The more fat, the more cancer. The less fat, the less cancer.

The difference is so dramatic, she adds, that "you can go to a country where there's almost no fat in the diet and people don't get colon cancer."

That's why she and other researchers recommend that you abandon the normal American diet, which gets 40 percent of its calories from fat, and aim for a diet in which 15 to 20 percent of calories come from fat.

To get started, get yourself a good low-fat cookbook, avoid high-fat dairy products and check food labels for fat content, suggests Dr. Sigurdson. "It can be a real eye-opener when you realize how much fat is in that yogurt you eat every day for lunch."

Ban booze. "Alcohol is bad," says Dr. Sigurdson. "Maybe it's because the martini crowd is also out eating high-fat steaks or maybe it's because alcohol is an oxidizing agent, but people who drink tend to have more colon cancer."

In a study of more than 15,000 women at Harvard Medical School, for example, researchers found that women who drank more than 30 grams of alcohol a day--the equivalent of two mixed drinks--had nearly double the risk of developing precancerous polyps as those who didn't imbibe at all.

Go for the fiber. "Fiber seems to have a protective effect on people who are predisposed to colorectal cancer," says gastroenterologist Marie Borum, M.D., assistant professor of medicine at Georgetown University School of Medicine in Washington, D.C.

It adds bulk to the stool and it helps absorb water. And that has three very helpful effects: It dilutes the concentration of any cancer-causing agents in the bowel, decreases the amount of time a potential carcinogen is in the bowel by speeding transit time through the bowel and increases the acidity of the colon, making it less hospitable to cancer-friendly bacteria.

"We generally try to say that you should get 25 grams of fiber into your diet every day," says Dr. Sigurdson. "But since the average North American eats between 2 and 5 grams a day, that's hard. It means eating an African-type diet of vegetables, legumes, beans and rice, with just a little bit of meat to add flavor."

Serve yourself fruits and veggies. Since fiber from fruits and vegetables has actually been more consistently related to a lower risk of colorectal cancer than fiber from grains, many experts feel that you should eat a balanced diet, but emphasize vegetables. The recommended combination is five servings of fruits and vegetables.

Crunch on crucifers. Cruciferous vegetables--cabbage, broccoli, cauliflower and brussels sprouts, for example--all seem to activate naturally occurring enzymes in your body, says researcher Christine Szarka, M.D., a medical oncologist at Fox Chase Cancer Center. Those enzymes can actually neutralize cancer-causing substances that are activated by free radicals. Whether cooked or raw cruciferous vegetables are more potent isn't known.

Laboratory tests of crucifers have been so encouraging that human trials are now under way, says Dr. Szarka. At the Fox Chase Cancer Center, for example, high-risk individuals--such as those with a genetic predisposition to colorectal cancer--are being given tablets of crushed and dehydrated broccoli. Study participants take two 500-milligram tablets three times a day. When the study is completed, intestinal biopsies and other tests will reveal whether crucifers can in fact prevent the growth of precancerous polyps, as researchers suspect.

Consider calcium. "Calcium is another way to scavenge up free radicals," says Dr. Sigurdson. It binds to potentially cancer-causing agents and escorts them out of the body.

Good sources of calcium include broccoli, spinach and low-fat dairy products. You should get at least 1,000 milligrams a day, but 1,200 milligrams is recommended if you're pregnant and 1,500 if you're menopausal but not on estrogen replacement therapy.

Talk to your doctor about aspirin. "People who take aspirin seem to have a lower mortality from colorectal cancer," says Dr. Sigurdson. And in an American Cancer Society study of more than a million men and women, researchers found that the risk of colon cancer itself was reduced 42 percent in those who used aspirin 16 or more times a month for at least one year.

Ask for a cancer screening. Despite the vigilance of some gynecologists, physicians in general are less likely to check for colorectal cancer. And when they do check, says Dr. Borum, for some unknown reason, they're more likely to check men than women.

In a study of 110 women and 90 men, Dr. Borum found that rectal examinations were performed on 36 percent of the women and 57 percent of the men. Stool samples were checked for hidden blood in 11 percent of the women and 14 percent of the men. A sigmoidoscopy--the insertion of a flexible tube into the lower part of the bowel so the physician can check for polyps--was performed on 13 percent of the women and 29 percent of the men. Because 80 percent of colorectal cancer strikes after age 50, the American Cancer Society recommends that a rectal exam be performed annually after age 40 in both men and women. Stools should be checked for hidden blood beginning at age 50, and sigmoidoscopy should also be performed every three to five years from that age.

There are other conditions that raise your risk of colorectal cancer, says Dr. Borum. Women who have irritable bowel syndrome, Crohn's disease or ulcerative colitis should be screened by colonoscopy--an outpatient procedure in which your doctor can view the entire colon--with a barium enema ten years after they develop the disease. Women who have a family history of colorectal cancer should begin their screening five years before the age at which the relative developed cancer.

Some research shows women who have had gynecologic cancer (breast, uterine, cervical or ovarian) may be at increased risk for colorectal cancer. And women who have a family history of polyps may also be at increased risk for cancer.

Have precancerous polyps removed. Removing any polyps detected by sigmoidoscopy or colonoscopy will prevent them from evolving into cancer, says Dr. Sigurdson. The polyps can be removed painlessly during a colonoscopy.