Cancer Prevention: What Works?
Soy, fish oil, and alcohol are still debated, but some things are certain: Stop smoking, lose weight, and exercise.
Controversial and Unproven
Although you might read about various links between cancer and certain lifestyle choices, many of these claims haven't impressed the serious scientists. Internet emails, for example, have proclaimed that chemicals in underarm antiperspirants are absorbed through the skin and interfere with normal circulation, causing toxins to build up and trigger breast cancer. But according to the American Cancer Society (ACS), there is "no experimental or epidemiological evidence to support this rumor."
One popular urban legend has implicated underwire bras as a cause of breast cancer, claiming that they obstruct lymph circulation, although the ACS insists that there is no credible research that supports this claim. There is probably no need to give up coffee, either -- at least not now. Caffeine may increase symptoms of fibrocystic breast lumps, but there is no proof that this benign breast disease increases the likelihood of breast cancer.
What Makes Sense?
So what should you do for cancer prevention? "At least 50% of cancers in the U.S. could be prevented just based on what we already know about risk factors," says Stein. Here are some recommendations to take seriously:
Stop smoking or using tobacco products. In 2002, tobacco use caused more than 430,000 deaths from cancer and other serious diseases. Tobacco is a major cause of preventable disease and premature death. It increases the risk for cancer of the lung, esophagus, pancreas, kidney, bladder, and uterine cervix. For cancer prevention, throw out your cigarettes and avoid secondhand or environmental tobacco smoke, too.
Protect your skin in the sun. The majority of skin cancers are caused by excess ultraviolet radiation exposure, most of which comes from the sun. Wear SPF 15 (or higher) sunscreen and a wide-brimmed hat to guard against skin cancer. Avoid direct sunlight during the hours when the sun's ultraviolet rays are the strongest (between 10 a.m. and 4 p.m.). The American cancer Society also recommends avoiding tanning beds and sun lamps.
Lose any excess pounds. About 64% of men and women in the U.S. were overweight or obese in 1999, based on data from the surgeon general, and over 25% of the U.S. population is obese. According to the ACS, about a third of all cancer deaths from 2002 were expected to be related to nutrition, physical inactivity, obesity, and other lifestyle factors and could have been prevented. An ACS study in the April issue of TheNew England Journal of Medicine suggests that about 14% of all cancer deaths in men and 20% of those in women are associated with excess body weight.
"If there were one perfect way to lose weight, you wouldn't go into the bookstore and find a hundred different diet books," says Litin. "It boils down to this: Healthy eating, consuming less calories than you burn up, and doing more exercise."
Fiber up. Although doctors continue to debate the cancer prevention effects of a diet rich in fiber (emphasizing whole-grain products, cereals, vegetables, and fruits), two major studies published in the British medical journal The Lancet in May found that the risk of colorectal cancer was reduced with high intakes of dietary fiber. In one of those studies, conducted in 10 European countries, the individuals who consumed the most dietary fiber (averaging 35 grams a day) experienced a 40% lower risk of colon cancer than subjects eating the least fiber (averaging 15 grams a day).
Exercise may help regulate hormones and "growth factors" that have been linked to cancer. According to Stein, all adults should accumulate at least 30 minutes of moderate-intensity activity on most days of the week, including walking, bicycling, gardening, dancing, and cleaning. This activity, she says, "does not need to be done all at once -- 10 minutes here and there add up."
Consider "chemoprevention." If you're at high risk for breast cancer (because of a strong family history, for example), your doctor may recommend taking a prescription drug called tamoxifen to reduce your chances of developing the disease. However, in a report in July 2002, the U.S. Preventive Services Task Force advised that the drug not be given to women with a low or average breast cancer risk.
Get tested. Annual screenings are advisable for all adults. Early detection, says Bevers, offers the best chance of successful treatment.