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Reducing the Risk of Breast Cancer

What Are the Risks?

Breast cancer is one of the most common forms of cancer in women. Each year, more than 20,000 women develop breast cancer in Canada and more than 5,000 women die of the disease. Based on current rates, one in nine women in Canada is expected to develop breast cancer during her lifetime. However, since 1993, the rate of new cases of breast cancer has stabilized, and death rates have steadily declined.

What You Need to Know

This pamphlet identifies biological and lifestyle risk factors associated with breast cancer and offers information and advice to help you better understand and address them. It also highlights environmental factors that may lead to increased risks, and identifies common misconceptions about breast cancer.

What You Need to Do

Be proactive. Increasing your awareness and knowledge may help reduce your risk of developing breast cancer. Take charge by knowing your body, watching for changes, and contacting your doctor if you have any questions or concerns.

Biological Risk Factors

While you can’t change biological risk factors, knowing about them allows you to better understand your risk level and will help you to discuss appropriate action with your doctor.

1. Being a woman

More than 99% of breast cancer occurs in women.

2. Getting older

Most breast cancer is found in women over 50. Women between the ages of 50 and 69 should have a mammogram (an x-ray of the breast that can find very small cancers before they can be felt) and clinical examination every one or two years. Talk to your doctor about the breast cancer screening program in your province or territory.

3. Family history

You have a greater chance of developing breast cancer if someone in your family has had breast cancer, particularly at a young age. Studies show that about 5-10% of breast cancer cases are hereditary. Women who have inherited a mutated gene related to breast cancer are at greatly increased risk of developing breast cancer. If you have questions about this, talk to your doctor.

4. Reproductive factors

Certain reproductive factors increase the risk of breast cancer:

• beginning to menstruate (have periods) before age 11;
• having a first baby after age 30, or never having a baby; and
• completing menopause after age 55.

5. Hormone replacement therapy

Discuss the risks and benefits of hormone replacement therapy (HRT) with your doctor and make the decision that’s best for you.

HRT is used to relieve symptoms of menopause such as hot flashes. Studies suggest that the use of certain types of HRT over several years may increase breast cancer risk. On the other hand, HRT can also decrease your risk of developing osteoporosis (thinning bones).

Lifestyle Risk Factors

Taking action on lifestyle risk factors can significantly lower your risk of breast cancer. It will also increase your overall wellness and reduce your risk of diabetes and heart disease.

1. Body weight

Maintain a healthy body weight. Being overweight increases your risk of developing breast cancer after menopause. In fact, each 5 kilogram (12 pound) weight gain translates to an approximate 8% increase in risk.

Talk to your doctor about how you can achieve a healthy body weight. For more information, consult the Canadian Guidelines for Body Weight Classification in Adults (www.hc-sc.gc.ca/fn-an/nutrition/ weights-poids/guide-ld-adult/qa-qr-pub_e.html).

2. Healthy eating

Maintaining a balanced diet and choosing lower-fat dairy products and leaner meats may help contribute to maintaining a healthy body weight. For more information on wise food choices, consult Canada’s Food Guide to Healthy Eating (www.healthcanada. gc.ca/foodguide).

3. Physical activity

Start exercising! Even if you’ve been inactive most of your life, you can greatly reduce your risk of developing breast cancer by becoming active now. Thirty to sixty minutes of moderate physical activity at least four days a week may reduce breast cancer risk by 30 to 40%.

Talk to your doctor or health care professional about a program that is right for you. Consult Canada’s Physical Activity Guide for exercise tips (www.paguide.com).

4. Alcohol consumption

Evidence suggests that drink- ing alcohol slightly increases a woman’s risk of developing breast cancer. The more alcohol a woman drinks, the higher her risk.

If you consume alcohol, limit your alcohol intake to one alcoholic drink a day:

• 12 ounces (340 mL) of beer,
• 5 ounces (140 mL) of wine, or
• 1.5 ounces (42 mL) of spirits.

5. Breastfeeding

Breastfeeding appears to reduce the risk of breast cancer, and the longer you breastfeed, the more you reduce your risk.

If you are a new mother, consider breastfeeding your baby. The Government of Canada recommends exclusive breastfeeding for at least the first six months of life for healthy term infants. (Exclusive Breastfeeding Duration – 2004 Health Canada Recommendation: www.hc-sc.gc.ca/fn-an/ nutrition/child-enfant/infant-nourisson/ excl_bf_dur-dur_am_excl_e.html)

6. Smoking

Quit smoking! Ask your doctor for advice on how to quit or look up e-Quit at www.gosmokefree.ca. If you don’t smoke, avoid breathing second-hand smoke.

Recent studies have found a link between breast cancer and tobacco smoking and breathing second-hand smoke. However, the effects are not fully understood and more research is needed. What is known is that more than 25% of all cancer deaths are caused by tobacco smoke.

7. Birth control pills

Talk to your doctor about the risks and benefits of using birth control pills. Some evidence suggests that the use of birth control pills may be associated with a slightly increased risk of developing breast cancer. However, research also indicates that birth control pills reduce a woman’s risk of developing endometrial and ovarian cancers.

8. The environment

Some researchers suspect that chemicals in our environment are increasing the risks of breast cancer for women. Although there is no evidence of a direct link between chemicals and breast cancer, we do not have all the answers about how chemicals affect our bodies. Until more is known, you should avoid or limit your exposure to chemicals.

• At home: Follow proper use and storage instructions for cleaning, painting and motor engine products and take proper safety precautions if you use pesticides in the garden.



• At work: Talk to your employer about ensuring good air quality and proper handling of chemicals. Read the material safety data sheets (MSDS) for chemicals and follow the directions, warnings and safe handling procedures.

Common Misconceptions

Many factors are often mistakenly associated with increased risk of breast cancer, such as underarm deodorants or antiperspirants, but they pose no additional risk for women.

The following factors pose no additional risk for breast cancer. Talk to your doctor or health care professional if you have questions or concerns about:

• fibroids;
• endometriosis;
• breast reduction or enlargement; and
• breast injury.

Acknowledgements

The Public Health Agency of Canada would like to thank the Canadian Breast Cancer Initiative for its assistance in developing this brochure.

Catalogue No.: HP35-1/2006
ISBN: 0-662-49201-3
© Her Majesty the Queen in Right of Canada (2006)