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Mammogram Frequently Asked Questions

Breast cancer screening is the regular examination of a woman's breasts to find breast cancer early. Mammography (breast X-ray) remains the best screening test for most women.

What is a screening mammogram?

Regular breast cancer screening is important because it can find cancer early when it may be smaller and easier to treat. Screening mammography can find breast cancers when they are small, less likely to have spread and more likely to be treated successfully.

Why have a screening mammogram?

Breast cancer is expected to be the most common cancer diagnosed in Ontario women in 2018 and occurs mostly in women ages 50 to 74 (61% of cases). Screening mammography can find breast cancers when they are small, less likely to have spread and more likely to be treated successfully.

When should women have screening mammograms?

Cancer screening is testing done on people who may be at risk of getting cancer, but who have no symptoms and generally feel fine. Your age and family medical history help determine when you should get screened:

  • The Ontario Breast Screening Program (OBSP) recommends that most women ages 50 to 74 get screened every 2 years with mammography. Find Ontario Breast Screening Program locations.
  • Women ages 30 to 69 can get screened through the High Risk OBSP if they have a referral from their doctor, have no acute breast symptoms and fall into one of the following risk categories:
    • You are known to have a gene mutation that increases your risk for breast cancer (e.g., BRCA1, BRCA2, TP53, PTEN, CDH1).
    • You are a first-degree relative of someone who has a gene mutation that increases their risk for breast cancer (e.g., BRCA1, BRCA2, TP53, PTEN, CDH1), have already had genetic counselling and have chosen not to have genetic testing.
    • You have been assessed at a genetics clinic (using the IBIS or BOADICEA tools) as having a 25% or greater lifetime risk of breast cancer based on personal and family history.
    • You have had radiation therapy to the chest to treat another cancer or condition (e.g., Hodgkin lymphoma) before age 30 and at least 8 years ago.

If you are ever worried about any problems with your breasts, see your doctor.

How effective are screening mammograms?

  • Screening mammography can find breast cancers when they are small, less likely to have spread and more likely to be treated successfully. Regular mammograms lower the risk of dying from breast cancer in women ages 50 to 74.
  • Mammograms are not perfect tests. They may miss some breast cancers. Also, some cancers develop in the time between screening visits. However, many studies have shown that regular mammograms reduce the risk of dying from breast cancer. 
  • Some breast cancers that are diagnosed through screening may never cause symptoms in a woman during her lifetime (i.e., overdiagnosis). Therefore, some women may have surgery or treatment for a breast cancer that would not have become life-threatening. 
  • Not all cancers found through screening can be treated successfully.

Are mammograms safe?

Mammograms are safe. Mammograms use a low dose of radiation. The benefits of screening and finding cancer early are more important than any potential harm from the X-ray.

What happens during the mammogram?

  • A registered medical radiation technologist specializing in mammography will place your breast on a special X-ray machine. 
  • A plastic plate will press down on your breast and hold it in place for a few seconds. 
  • You will feel some pressure on your breast for a few seconds during the X-ray. This pressure does not harm your breast tissue. 
  • Typically 4 pictures are taken, 2 of each breast. 
  • The technologist will check the pictures to make sure the quality is acceptable for the radiologist to read. If needed the technologist will take additional pictures. 

How does it feel?

You will feel some pressure on your breast. It feels similar to a tight blood pressure cuff. A few women experience pain, but it lasts only for a few seconds. If you feel pain during the X-ray, tell the technologist. The technologist maybe able to adjust the pressure. The two of you can work together to make it as comfortable an experience as possible.

How to get ready for a mammogram?

Try to book your mammogram for a time when your breasts are not tender. Most women’s breasts are tender the week before and after their period. 

The day of your mammogram 

  • Wear a 2-piece outfit. You will be asked to remove your top before your mammogram. 
  • Do not use deodorants, antiperspirants, body lotions or talcum powders. Metals in these products can show up on the X-ray picture. 

Where should I go to have a mammogram?

You should go to an Ontario Breast Screening Program location. All OBSP sites are accredited by the Canadian Association of Radiologists (CAR) Mammography Accreditation Program.

What happens if more tests are needed?

  • Your OBSP site will notify your healthcare provider of the mammogram results and will help to schedule a timely follow-up appointment.
  • If you do not have a healthcare provider, you will be assigned a doctor who will follow you until you have a diagnosis.

Keep in mind that most women needing more tests do not have breast cancer:

  • Most women with abnormal mammogram results will not have breast cancer. 
  • Most women who need follow-up tests have non-invasive procedures, such as special mammographic views and/or ultrasounds.