How can I prevent HER2-positive breast cancer?

There's no way to guarantee you won't develop HER2-positive breast cancer -- or any type of breast cancer -- but you can reduce your risk for breast cancer by making certain lifestyle choices. On average, women have about a one in eight chance of being diagnosed with breast cancer during their lifetime. Among women who do develop breast cancer, about 20% will have HER2-positive breast cancer.

There are some risk factors for breast cancer that you can't control and others that you can. Breast cancer risk factors you can't control include:

• your sex. Women are 100 times more likely to develop breast cancer than men.
• your age. Your risk for breast cancer increases as you get older, especially once you pass 50. 
• your menstrual history. If you started menstruating before age 12 and/or you continued menstruating into your late 50s, you may be at increased risk for most kinds of breast cancer. 
• your family history. If an immediate family member had breast, uterine, ovarian or colon cancer, your risk for breast cancer is higher. About 20% to 30% of women diagnosed with breast cancer have a family history of the disease. 
• your genes. Certain genes increase your risk for breast cancer. Ask your doctor if your family history suggests you should be tested for these genes.

Risk factors for breast cancer that you can control include:

• your diet. Some studies show that a diet rich in fruits, vegetables, fish, poultry and low-fat dairy products may lower breast cancer risk.
• your activity level. Doing moderate to vigorous exercise may lower your breast cancer risk. 
• your weight. Being overweight, especially if you've gained the weight as an adult, may raise your risk of developing breast cancer.
• your drinking habits. Drinking more than one to two alcoholic beverages per day may raise your risk for most breast cancers. 
• having children. Women who never have children or who don't have their first child until they are over age 30 have a higher risk for breast cancer compared with women who have children at younger ages.
• breastfeeding. Nursing a child may reduce your breast cancer risk.
• taking hormones. Women who use hormones for more than a relatively brief period after menopause may be at increased risk of most kinds of breast cancer.

Talk to your doctor about your risk. If your doctor determines that you are at high risk for breast cancer, you may be able to take certain medications or consider other strategies for lowering your risk.