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

If you follow the screening guidelines for breast cancer, the cancer can be found before you notice symptoms. Follow the guidelines even when you feel well and healthy.

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

  • If you are 50–69 years old, have a mammogram every 2 years.
  • If you are 40–49 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, you should keep it to less than 1 drink a day. The less you drink, the more you lower your risk.

Have 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.

Be physically active

Research shows that you can lower your risk of breast cancer by being physically active.

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 and, in turn, breast cells’ exposure to estrogen. The longer a woman breastfeeds, the greater the 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, lowers the risk that a woman will develop breast cancer in her lifetime. Each additional birth further lowers the long-term risk of developing breast cancer.

Find out if you’re at high risk for breast cancer

Some people can have a higher than average risk for breast cancer. Talk to your doctor about your risk. If you are at higher than average risk, you may need to visit your doctor more often to check for breast cancer. Your doctor will recommend what tests you should have and how often you should have them.

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, such as tamoxifen (Nolvadex, Tamofen), 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 who have a high risk of 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 lower the risk.

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 show that prophylactic mastectomy results in about a 90% decrease in the risk for 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. Be sure to discuss other options for lowering risk, such as close surveillance and chemoprevention. For some women who have a very high risk of developing breast cancer, this surgery may be the right choice after weighing the benefits and risks.

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 for breast cancer in women with BRCA mutations. It can also lower their risk for 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. Discuss other options for lowering risk as well. For some women who have a very high risk of developing breast cancer, this surgery may be the right choice after weighing the benefits and risks.

More information about reducing cancer risk

Learn what you can do to prevent cancer.

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