• Mayo Clinic Q and A: Lifestyle changes that can lower your risk of cancer

a middle-aged woman looking at a laptop screen, with a concerned look on her faceDEAR MAYO CLINIC: It seems like I see a new story every day about things I should or shouldn’t do to prevent cancer — and the list feels endless. What really makes a difference? Are there some steps I can take that science has proven will lower my chance of getting cancer?

ANSWER: This is a wonderful question. Although each individual’s risk of cancer is different, depending on factors such as medical history, family history and ethnic background, research clearly shows there are several significant lifestyle changes that can lower the risk of cancer.

A recent study by the American Cancer Society found that 45 percent of cancer deaths and about 40 percent of diagnosed cancer cases can be attributed to risk factors you can do something about.

Not surprisingly, the one that has the biggest effect is smoking and other forms of tobacco use. Awareness about the health risks of smoking has grown significantly. Accordingly, the number of lung cancer deaths attributed to smoking is declining. But smoking remains the largest preventable cause of cancer.

The best approach to smoking is not to start. If you smoke, however, stopping now will make a difference. Quitting smoking or other use of tobacco significantly lowers your risk of lung cancer, as well as cancers of the mouth, throat and esophagus; bladder; kidney; and pancreas.

Another lifestyle factor to consider is sun exposure. Unlike lung cancer, which is decreasing, skin cancer is rising. Many cases of skin cancer are related to the effects of too much time in the sun without proper skin protection. Take precautions whenever you’re in the sun. Wear a broad-spectrum sunscreen with a sun protection factor, or SPF, of at least 30. Reapply it often. Avoid the midday sun. Wear protective clothing, sunglasses and a hat with a wide brim. If you’re a parent, take extra care to shield your children from the sun. People who have multiple blistering sunburns as children are at high risk for developing melanoma — a particularly dangerous form of skin cancer.

A third way you can lower your risk of cancer is to be careful with the amount of alcohol you drink. Excessive alcohol has been shown to contribute to liver, stomach, mouth and throat cancer. To stay in the low-risk range, women should have no more than three drinks in any one day and no more than seven drinks a week. For men, it is no more than four drinks a day and no more than 14 drinks a week.

Controlling your weight makes a difference, too. This risk affects men and women, but it seems to have a greater effect on women. Research has found that women who are obese are at increased risk for breast and uterine cancer. Several other factors often act in conjunction with weight to raise cancer risk. They include a diet high in fats, lack of regular exercise and a sedentary lifestyle. When these factors are combined, they increase the risk of multiple types of cancer in men and women.

Vaccinations also help prevent certain types of cancer. Vaccination against the hepatitis B virus decreases the risk of liver cancer. The HPV vaccine is recommended for all boys and girls before they become sexually active because it can prevent the most common cause of cervical cancer and penile cancer, as well as cancers of the throat and mouth.

Although the factors mentioned here are not the only ones that affect your cancer risk, they are some of the most significant, modifiable risk factors that apply to everyone. If you’d like to learn about your specific cancer risk, have a discussion with your health care provider about your individual risk factors and how you may be able to lower your overall risk for cancer. — Dr. Timothy Moynihan, Medical Oncology, Mayo Clinic, Rochester, Minnesota

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