Screening for breast cancer

Screening mammography

Breast screening programs

Clinical breast exam (CBE)

Knowing your breasts


When breast cancer is detected and treated early, the chances of successful treatment are better. Screening tests help find breast cancer before any symptoms develop. Screening means checking or testing for disease in a group of people who don’t show any symptoms of the disease.


Women should talk to their doctor to learn more about their personal risk of breast cancer and to take advantage of screening tests or programs.


Currently in Canada, screening for breast cancer is recommended for women who are 50–69 years of age.


The most reliable method of finding breast cancer early is screening mammography.

Screening mammography

Screening mammography is done in a clinic or screening centre.

  • Women who are 50–69 years of age should have screening mammography every 2 years.
  • Women between the ages of 40 and 49 should discuss their risk of breast cancer, along with the benefits and risks of mammography, with their doctor.
    • There is some suggestion that women aged 40–49 could benefit from regular mammography, but there are conflicting results in the research about whether this saves lives.
    • Research also suggests that if women in their 40s choose to have a mammogram, they should consider having one every year (instead of every 2 years for women aged 50-69). This is because breast cancers may act differently in younger women.
  • Women 70 years of age or older should talk to their doctor about a screening program that would be appropriate for them.


Potential risks of mammography include:

  • results that shows there is cancer or a precancerous condition when there isn’t (false-positive)
  • increased exposure to radiation
    • Modern mammography equipment uses very low doses of radiation, but repeated exposure to x-rays does increase the risk of developing cancer. The benefits of mammography and finding breast cancer early outweigh the risk of repeated exposure to radiation.

High-risk individuals

Women who are at higher than average risk of developing breast cancer may need to be tested more often or earlier than people with average risk. Examples of what may put a woman at higher than average risk include:

  • a strong family history of breast cancer
  • certain gene mutations, such as BRCA1 or BRCA2 mutations
  • a history of breast biopsies showing certain breast changes, such as:
    • lobular carcinoma in situ (LCIS) – abnormal cells found in the breast lobules
    • ductal carcinoma in situ (DCIS) – abnormal cells found in the breast ducts
    • atypical hyperplasia – increased number of cells that look abnormal but are not cancerous


Women who are at higher than average risk should talk to their doctor about a personal plan of testing. A personal plan of testing may include:


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Breast screening programs

All provinces and territories have organized breast screening programs, each with specific guidelines. Breast screening programs vary among the provinces and territories.


Women who meet the age criteria are automatically invited to participate in the breast screening program in their province.

  • Women between the ages of 50 and 69 can contact their provincial or local breast screening program to book an appointment. A doctor’s referral is not needed.
  • Some programs allow younger or older women to participate.
    • Check with your provincial or local screening program for details about screening mammography for a particular age group or if you have questions about participating in the program.

What happens after screening

The screening program gives the results to the woman and her doctor.


If the screening mammogram reveals a change or an abnormality that needs follow-up, the woman’s doctor is notified. The doctor will decide if more tests are needed. About 6–7 women out of 100 will need more tests after a screening mammogram. A diagnostic mammography is the most common follow-up test and is used to focus on suspicious areas.


Screening programs send letters reminding women when to have their next screening mammogram.


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Clinical breast exam (CBE)

A clinical breast exam (CBE) is a thorough examination of the breast by a trained healthcare professional to check for abnormalities. Research has not shown that CBE is an effective screening tool, but it may still help doctors diagnose an abnormality in the breast or arm pit (axilla).


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Knowing your breasts

Breast health starts with knowing your breasts. All women should be aware of what is normal for their breasts even if they get regular screening tests. Many women discover their own breast cancer through changes in the look and feel of their breasts.


Women can become familiar with their breast tissue by looking at and feeling their breasts. Experts used to suggest that this should be done by following a particular method every month. Research has shown that this isn’t necessary. There really isn’t a right or wrong way for women to examine their breasts, as long as they get to know the whole area of their breast tissue – up to the collarbone, under the armpits and including the nipples – well enough to notice changes.


Most changes are not cancerous. It may be normal for your breasts to be lumpy or tender before your period. It is important for a woman to report any unusual changes to her doctor.


See a list of questions to ask your doctor about screening.


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