More than ever before, women are taking an active part in their breast health. At the centre of this change is our growing concern and understanding of breast cancer, the second most common cause of cancer deaths in women.

What is breast cancer?

Cells in the body normally divide (reproduce) only when new cells are needed. Sometimes cells will divide for no reason, creating a mass of tissue called a tumour. Tumours can be benign (not cancerous) or malignant (cancerous).

In breast cancer, as well as in some other cancers, a tissue cell becomes abnormal and reproduces without control or order, forming a malignant tumour. Cancer cells can break off from the tumour, travel to other parts of the body, and form new tumours. This process is called metastasis. Metastasis is a late stage of cancer.

Am I at risk for developing breast cancer?

If you are a woman, you are at risk. (Men can also develop breast cancer, but this is rare.) You may be more likely to develop breast cancer if you have one or more risk factors, but risk factors do not cause breast cancer. However, not having a risk factor does not mean that you cannot get breast cancer.

In many cases, it's not known why a woman develops breast cancer. In fact, 70 percent of all women with breast cancer have no known risk factor.

What are the risk factors of breast cancer?

A risk factor is anything that increases a person’s chance of getting a disease. Different cancers have different risk factors.




  • History of previous cancer in one breast, especially if it occurred before menopause, increases a woman’s risk of developing a new breast cancer unrelated to the first one. This is different from a recurrence of the previous breast cancer.
  • Genetics also plays a role. Carriers of either of two familial breast cancer genes called BRCA1 or BRCA2 are at higher risk. Ten percent of women are carriers of these genes. Also, 10 percent of all breast cancers are thought to be from either gene. In addition, the risk of getting breast cancer is up to 85 percent in a woman’s lifetime if she has inherited these genes.




  • Getting older. Your risk for breast cancer increases as you age. About 77 percent of women diagnosed with breast cancer each year are over age 50, and almost half are age 65 and older. Consider this: In women 40 to 49 years of age, there is a one in 66 risk of developing breast cancer. In the 50 to 59 age group, that risk increases to one in 40.
  • Direct family history. Having a mother, sister, or daughter (a "first-degree relative") who has breast cancer puts you at higher risk for the disease. The risk is even greater if your relative developed breast cancer before menopause and had cancer in both breasts. Having one first-degree relative with breast cancer approximately doubles a woman’s risk. Having two first-degree relatives with breast cancer increases her risk five-fold. Having a male blood relative with breast cancer may also increase a woman’s risk of the disease.
  • Breast lesions. These include multiple papillomatosis, atypical ductal hyperplasia, and atypical lobular hyperplasia.




  • Distant family history. This refers to breast cancer in more distant relatives such as aunts, grandmothers, and cousins.
  • Large cysts in the breast. Large cysts increase your risk, especially if accompanied by early atypical hyperplasia (abnormal cell changes in the breast). A previous breast biopsy result of atypical hyperplasia increases a woman’s breast cancer risk by four to five times.
  • Age at childbirth. Having your first child after age 30 or never having children puts you at higher risk.
  • Early menstruation. Your risk increases if you got your period before age 12.
  • Late menopause. If you begin menopause after age 55, your risk increases.
  • Weight. Being overweight (especially in the upper body), with excess caloric and fat intake, increases your risk, especially after menopause.
  • Excessive radiation. This is especially true for women who were given radiation for postpartum mastitis, received prolonged fluoroscopic X-rays for tuberculosis, or who were exposed to a large amount of radiation before age 30 (usually as a treatment for cancers such as lymphoma or Hodgkin’s disease).
  • Other cancer in the family. A family history of cancer of the ovaries, cervix, uterus, or colon increases your risk.
  • Heritage. Female descendants of Eastern and Central European Jews (Ashkenazi) are at increased risk.
  • Race. Breast cancer occurs more frequently in Caucasian women than in Hispanic, Asian, or African-American women.
  • Alcohol. The use of alcohol is linked to increased risk of developing breast cancer. Compared with non-drinkers, women who consume one alcoholic drink a day have a 10 percent increase in risk, and those who have two or three drinks daily have about 20 percent to 30 percent higher risk than women who drink no alcohol. Alcohol is also known to increase the risk of developing cancers of the mouth, throat, and oesophagus.
  • Hormone replacement therapy. Long term use of combination oestrogen-progestin hormones taken during menopause increase a woman’s risk of developing breast cancer. This risk increases with longer use of hormones. Use of Oestrogen therapy only has not been shown to increase the risk of breast cancer.
  • Smoking. Accumulating evidence supports an association between active and passive tobacco smoking and increased breast cancer risk, particularly in premenopausal women.



  • Pregnancy before age 18
  • Early onset of menopause
  • Surgical removal of the ovaries before age 40



  • Fibrocystic breast changes
  • Multiple pregnancies
  • Coffee or caffeine intake
  • Antiperspirants
  • Underwire bras
  • Abortion
  • Breast implants


There are other factors that may affect your risk for breast cancer, but medical research has not yet determined the exact role they play. One of these is long-term use of birth control pills. Scientists are also investigating whether smoking, high-fat diets, lack of exercise, and environmental pollution increase breast cancer risk.


How can I protect myself from breast cancer?

  • Get a mammogram:
  • Baseline mammogram at age 35
  • First mammogram by age 40
  • Ages 40 and over: every year
  • Examine your breasts each month.
  • Have your breasts examined by a health care provider at least once a year.


Back to Articles

* Results may vary from person to person