Breast cancer

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Reducing your risk for breast cancer

You may lower your risk of developing breast cancer by doing the following.

Follow cancer screening guidelines

Screening means checking or testing for disease in a group of people who don’t show any symptoms of the disease. Screening tests help find breast cancer before you notice symptoms.

Provincial and territorial screening programs use screening mammography. A mammography is a low-dose x-ray of the breast. It is the most reliable method of detecting breast cancer early in women. Follow these breast cancer screening guidelines even if you feel healthy:

  • If you are 50 to 69 years old, have a mammogram every 2 years.
  • If you are 40 to 49 years old, talk to your doctor about your risk for breast cancer and the benefits and risks of mammography.
  • If you are 70 years of age or older, talk to your doctor about how often you should have screening mammography.

Find out more about screening for breast cancer and mammography. Talk to your doctor about a personal plan for testing if you think you might have a higher than average risk for breast cancer.

Limit the amount of alcohol you drink

Drinking alcohol can increase your risk of developing breast cancer. If you choose to drink alcohol, women should keep it to less than 1 drink a day.  The less you drink, the more you reduce your risk.

Maintain a healthy body weight

Research shows that being obese increases your risk of breast cancer. You can lower your risk by having a healthy body weight. Eating well and being physically active can help you have a healthy body weight.

Talk to your doctor about the benefits and risks of HRT

Discuss the benefits and risks of hormone replacement therapy (HRT) and its alternatives with your doctor. Women at high risk for breast cancer are often advised not to take HRT because of the relationship between estrogen and breast cancer.

Find out more about hormone replacement therapy (HRT).

Be a non-smoker and avoid second-hand smoke

If you smoke, get help to quit. Avoid second-hand smoke.

Learn about protective factors

Some lifestyle choices may help to protect you from developing breast cancer.

Breastfeeding

Research shows that breastfeeding protects against breast cancer. This is because breastfeeding can lower a woman’s total number of menstrual cycles. The longer a woman breastfeeds, the greater the hormonal protective effect against breast cancer.

There are many different reasons why women may choose not to breastfeed, and it may not be possible for every mother and baby.

Having children

Having at least one full-term pregnancy, particularly before the age of 30, lessens the risk of breast cancer during a woman’s lifetime. Each additional birth further lowers the long-term risk of developing breast cancer.

Find out if you’re at high risk

Some women have a higher than average risk for breast cancer. Talk to your doctor about your risk. If it’s higher than average, you may need a personal risk reduction strategy.

Chemoprevention

Selective estrogen-receptor modulators (SERMs) are anti-estrogen drugs. They block the effects of estrogen in some tissues, such as breast tissue, and act like estrogen in other tissues. Some SERMs like tamoxifen (Nolvadex) are used to treat breast cancer. Tamoxifen also lowers the risk of getting breast cancer in women at high risk of developing the disease. But this drug increases the risk of uterine (endometrial) cancer.

Women with BRCA2 gene mutations may benefit from taking tamoxifen. This is because if they develop breast tumours, the tumours are more likely to be estrogen-receptor positive. Breast tumours linked with BRCA1 mutations are more likely to be estrogen-receptor negative.

Women at high risk for developing breast cancer or those with BRCA2 gene mutations should talk to their doctor about the benefits and possible risks of taking tamoxifen or other SERMS to reduce the risk of breast cancer.

Prophylactic mastectomy

Having one or both breasts removed by surgery before cancer develops is called prophylactic mastectomy. This surgery may be an option for some women who have a very high risk of developing breast cancer. Some women consider having this surgery if they have a known BRCA gene mutation or if they already had cancer in one breast. Although many women with BRCA mutations can develop breast cancer, some will not.

Breast cancer can still develop in the small amount of breast tissue left behind after prophylactic mastectomy, but this rarely happens. Studies have shown that prophylactic mastectomy results in about a 90% decrease in the risk of breast cancer in high-risk women.

The decision to have a prophylactic mastectomy should be carefully considered. Talk to your doctor about all the risks and benefits of the procedure. Other options for reducing risk, such as close surveillance and chemoprevention, should also be discussed. However, this surgery may be the right choice for some women who have a very high risk of developing breast cancer.

Prophylactic oophorectomy

Surgically removing both ovaries before cancer develops is called prophylactic oophorectomy. The ovaries are the body’s main source of estrogen, so removing them lowers the level of estrogen in the body. This can lower the risk of breast cancer in women with BRCA mutations. It can also lower their risk of ovarian cancer.

Removing the ovaries will put a woman into menopause. Some women may decide to have their ovaries removed after they’ve finished having children.

The decision to have a prophylactic oophorectomy should be carefully considered. Talk to your doctor about all the risks and benefits of the procedure. Other options for reducing risk should also be discussed. This surgery may be the right choice for some women who have a very high risk of developing breast cancer.

More information about reducing cancer risk

Learn about what you can do to reduce cancer risk.

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