Tips for preventing cancer

Nov 12 2009

The risk of cancer can be dramatically reduced through everyday choices about diet, exercise and tobacco use, according to a Special Report on Cancer Prevention in the November issue of Mayo Clinic Women's HealthSource.

Evidence suggests that one-third of the more than 560,000 cancer deaths that occur in the United States annually are related to diet, exercise and weight. Another one-third of annual cancer deaths are related to tobacco exposure. The eight-page Special Report examines the science and latest findings on 10 approaches that can make a real difference in preventing cancer. Here are some highlights from the list:

1. Don't smoke: The risk of smoking-related cancers increases with the length of time a person has smoked and the number of cigarettes smoked. The most common cancer associated with smoking is lung cancer, the leading cause of cancer death among American women and men. Quitting smoking reduces the risk of lung and other cancers -- regardless of the number of years of smoking.

2. Eat fruits and vegetables: The American Cancer Society recommends eating at least five servings of fruits and vegetables daily because they are loaded with vitamins, minerals, antioxidants and other substances that lower the risk of cancer. In recent years, some studies have indicated that the association between eating fruits and vegetables and lower cancer risk isn't as strong as once thought. Most experts still believe that a plant-based diet is one of the best ways to protect overall health.

3. Limit fat in the diet: Studies suggest that high-fat diets or high intakes of certain types of fat may be linked to several types of cancer, including colon, lung and postmenopausal breast cancer. The reason may be that high-fat diets tend to be higher in calories and increase the risk of obesity. More study is needed to better understand which types of fat should be avoided and how much of each alters cancer risk.

Current guidelines recommend keeping fat intake between 20 and 30 percent of total daily calories, with most fats coming from sources of polyunsaturated and monounsaturated fats, such as fish, nuts and vegetable oils.

4. Maintain a healthy weight: Being overweight or obese can increase the risk of postmenopausal breast cancer as well as cancers of the colon, endometrium, esophagus and kidney. There's evidence that obesity increases the risk of cancers of the prostate, liver, gallbladder, pancreas, stomach, ovary and cervix. Some studies estimate that excess weight is a factor in 14 to 20 percent of all cancer-related deaths in American adults.

5. Be physically active: Evidence increasingly suggests that people who are physically active have lower risk of some cancers than those who are more sedentary. From 45 to 60 minutes of moderate to vigorous activity a day, on most days of the week, is considered optimal to reduce the risk of breast and colorectal cancers.

6. Curb alcohol consumption: Alcohol consumption increases the risks of cancers of the mouth, pharynx, larynx, esophagus, liver, colon and rectum. Women should limit themselves to no more than one alcoholic beverage a day. Men should have no more than two.

7. Limit exposure to radiation: Ultraviolet (UV) radiation, which comes from the sun, sunlamps or commercial tanning beds, is the primary cause of skin cancer, the most common of all cancers.

8. Protect against infection: Infections caused by viruses are recognized as risk factors for several types of cancer. Human papillomavirus (HPV), a sexually transmitted disease, is the most common cause of cervical cancer. Chronic hepatitis B and hepatitis C increase the risk of liver cancer. They are most often spread through contact with contaminated blood, from contaminated needles or by having unprotected sex. Human immunodeficiency virus (HIV), the virus that causes AIDS, also increases the risk of several types of cancer. It's most commonly transmitted by unprotected sex or sharing of needles.

9. Consider chemoprevention: Chemoprevention is the use of natural or synthetic compounds to reduce the risk of cancer or its recurrence. Tamoxifen, prescribed to prevent breast cancer in high-risk women, is the best known chemoprevention agent. A caution: chemoprevention drugs can have serious side effects.

10. Get recommended screening exams: Pap tests, mammograms, colonoscopies and other routine screenings can't prevent cancer. But screenings can help find cancers early, when treatment is most likely to be successful.