Breast Cancer

Public Health Agency of Canada reports that breast cancer is the most common cancer diagnosed among Canadian women.

Despite slight declines in death rates over the past decade for women with breast cancer, one in nine Canadian women will develop breast cancer in her lifetime and one in 25 Canadian women will die from this disease. 

More than 99 per cent of breast cancers occur in women.

What is breast cancer?

Breast cancer is an uncontrolled growth of breast cells. It is always caused by a genetic abnormality (a "mistake" in the genetic material) whether inherited or resulting from the aging process.

Usually breast cancer either begins in the milk-producing glands, or the ducts (the milk passages to the nipple). Less commonly, breast cancer can begin in the fatty and fibrous areas of the breast.

Over time, cancer cells can invade nearby healthy breast tissue and make their way into the underarm lymph nodes. If cancer cells get into the lymph nodes, they have a pathway into other parts of the body.

What are the risk factors?

Scientific researchers aren't certain of the direct causes of breast cancer, but have identified proven risk factors:

  • Increasing Age
  • Country of Birth / Residence
  • Family History
  • Previous Breast Cancer
  • Breast Density
pink ribbon in support of breast cancer

Other Possible Risk Factors

It's important to remember most breast cancers occur in women with no other risk factors than being a woman and increasing age.

Research continues to study other factors that may increase a woman's overall risk of developing breast cancer.

These possible risk factors include:

  • Early menstruation (before the age of 12)
  • Reaching menopause later than average
  • Having a first baby after age 30 or never having a baby
  • Being physically inactive
  • Being overweight
  • Drinking too much alcohol
  • Taking hormone replacement therapy

What is breast cancer screening?

Breast screening includes mammography (a breast x-ray) and a physical examination of the breasts by a trained health care provider. Regular breast screening can find cancer when it is small and has better outcomes for treatment.

How Often Should I Be Screened?

Screening Mammogram is recommended every two years for women between the ages of 50 and 74.

Depending on the advice of a healthcare professional and a woman's personal risk factors, this recommendation may be adjusted.

The Ontario Breast Screening Program (OBSP) is a Cancer Care Ontario program which provides breast cancer screening services to women aged 50 to 74 years of age.

This service is provided free of charge and women between the ages of 50 and 74 may call to book their own appointment without getting a referral from their doctor.

The OBSP offers the following services for women aged 50 to 74 years:

  • High-quality mammograms in sites accredited by the Canadian Association of Radiologists
  • Well-developed quality assurance at each site 
  • Results of the screening appointment within two weeks to you and your healthcare provider 
  • Help to set up extra tests or referrals if your results suggest that they are needed
  • A reminder letter when it is time to return for your next screening mammogram. Usually, this is every two years. Women over the age of 74 do not receive a reminder letter. However, they are welcome to call for an appointment after they have discussed it with their healthcare provider

To book a free mammogram call one of the seven OBSP sites in the Region of Waterloo:


Cambridge Memorial Hospital519-740-4999
Medical Imaging Centre - OBSP Cambridge519-740-3736
True North Imaging - Canamera X-Ray & Ultrasound519-623-9464


True North Imaging (Kitchener & Waterloo sites)
Victoria St. South, Kitchener
University Ave. East Waterloo
St. Mary's General Hospital519-749-6465
Waterloo Wellington Breast Centre
- Freeport Health Centre

The OBSP has been expanded to screen women ages 30 to 69 years who are at high risk of breast cancer. Less than 1 per cent of women in the general population are considered high risk. Talk to your doctor or nurse practitioner about getting a referral to an OBSP site if you are between 30 and 69 years of age and believe you are at high risk.

Breast cancer resources

Hook-up to Breast Cancer Prevention - Peer Education Training

Cancer Care Ontario

Canadian Cancer Society 

Ministry of Health and Long Term Care - Breast cancer fact sheets are available in 26 different languages from the Ministry of Health and Long Term Care

Public Health Agency of Canada