Risk Factors Breast Cancer

Risk Factors for Breast Cancer

Things that make a person more likely to get breast cancer are called breast cancer risk factors. There is no single cause of breast cancer but some factors appear to increase the risk of developing the disease. Some women with these risk factors never get the disease; however, it is important to be aware of them.

Risk factors for breast cancer include:

Being a women

Women have a much higher chance of developing breast cancer than men. Men only account for one per cent of cases.

Increasing age

Age is the most significant risk factor for breast cancer in women. Forty-nine per cent of breast cancers are found in women 50 to 69 years of age and 30% of cancers are found in women 70 years of age and older.

A family history of the disease

A strong family history refers to having a mother, sister, or daughter who is found to have breast cancer before menopause. It also includes a mother, sister or daughter who has cancer of the ovaries at any age. Women with a strong family history should talk to their doctor about screening that is right for them.

Previous breast cancer diagnosis

Breast cancer generally reoccurs in the same area where the original cancer had occurred.

Country of birth or country where you live

For many years incidence rates of breast cancer have been highest in North America and Northern Europe. There have been recent marked increases in incidence and mortality rates in several Asian and Central European countries. Thus, the differences between high-risk and low-risk countries have decreased in recent years. When women move from a low-risk country to a high-risk country they develop a similar risk as the new country. This is likely due to environmental and lifestyle factors.

Breast density over 75%

You cannot feel whether you have dense breasts. Breast density can only be seen on mammograms (breast X-rays). We know that women aged 50 and over with dense breasts are at higher risk for breast cancer.

Hormonal (exposure to estrogen)

Breast changes take place with each menstrual cycle. These changes can magnify the abnormalities in the cell repair process leading to breast cancer later on in life. With more menstrual cycles there is more exposure to estrogen and there may be more of a chance for changes that lead to breast cancer. The following may increase your risk of breast cancer as a result of estrogen exposure:

Early periods starting before age 12
Late menopause after age 55
Never having had a child or late age of first pregnancy over age 30
Use of hormone replacement therapy for long periods of time
Using the birth control pill
Never having breastfed ^{2, 3}

Talk to your doctor or health care provider about your risk factors.

Adapted from:

1. Summary Report: Review of Lifestyle and Environmental Risk Factors for Breast Cancer. Health

Canada, 2001.

2. Breast cancer and breastfeeding: Collaborative reanalysis of individual data from 47

epidemiological studies in 30 countries, including 50 302 women with breast cancer and 96

973 women without the disease. The Lancet, 2001

3. Lactation and breast cancer risk: a case-control study in Connecticut. British Journal of

Cancer,2002.

4. Breast Health: What you can do. Canadian Cancer Society, 2007.

5. Ontario Breast Screening Program, 2007.

For more information, or to speak with a Public Health Nurse, please contact

York Region Health Connection at 1 800-361-5653, TTY 1-866-252-9933

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