Screening for Breast Cancer

Your age and family medical history help determine when you should get screened:

• If you are age 40 to 49, the Ontario Breast Screening Program encourages you to talk with your family doctor, your nurse practitioner or a Health811 navigator to make an informed decision about whether breast cancer screening is right for you. Most people in your age group who decide to get screened for breast cancer should get screened with mammography every 2 years.
• If you are age 50 to 74, the Ontario Breast Screening Program recommends that most people in your age group get screened every 2 years with mammography.
• If you are age 30 to 69 and meet any of the following requirements, talk to your doctor or nurse practitioner about referral to the High Risk Ontario Breast Screening Program:
  • You are known to have a gene mutation that increases your risk for breast cancer (e.g., BRCA1, BRCA2, TP53, PALB2).
  • You are a first-degree relative (parent, sibling or child) of someone who has a gene mutation that increases their risk for breast cancer (e.g., BRCA1, BRCA2, TP53, PALB2).
  • You have a personal or family history of breast or ovarian cancer.
  • 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.

The Ontario Breast Screening Program offers breast cancer screening to women, Two-Spirit people, trans people and nonbinary people ages 40 to 74 if they:

• have no breast cancer symptoms
• have no personal history of breast cancer
• have not had a mastectomy
• have not had a screening mammogram within the last 11 months
• If transfeminine, have used feminizing hormones for at least 5 years in a row

If you are over age 74, you are encouraged to talk with your family doctor or nurse practitioner to make an informed decision about whether continuing to get breast cancer screening is right for you. If you decide to continue breast cancer screening through the Ontario Breast Screening Program, you will need a referral (order) from a family doctor or nurse practitioner. The Ontario Breast Screening Program does not send letters to people over age 74 telling them when to get screened and giving them their test results.

Mammography remains the best screening test for most people. A screening mammogram takes an X-ray picture of the breast.

Mammograms are considered safe and use a low dose of radiation. Most people will have normal mammogram results.

Potential Benefits of Regular Breast Cancer Screening

Getting screened regularly can find breast cancer earlier which may mean that:

• the chance of dying from breast cancer is lower
• treatment has a better chance of working
• fewer treatments may be needed and the treatments may be less invasive (easier to handle)

Screening can be part of taking an active role in protecting your health. Getting a normal result from a mammogram can be reassuring for some people.

Potential Harms of Regular Breast Cancer Screening

• False-positive: Getting an abnormal result when there is no cancer present. It can lead to extra testing, like a biopsy (taking a small sample of tissue), that can cause anxiety and stress for some people.
• False-negative: Missing a cancer on a screening mammogram, which could lead to delayed treatment.
• Overdiagnosis: Finding a cancer that would not otherwise cause health problems, that may lead to unneeded surgery or treatment.

To learn more about what happens during a mammogram and how to get ready for a mammogram, see Mammograms.

You can make your own appointment for a mammogram:

• Call an Ontario Breast Screening Program location directly or call our Appointment Booking Line at 1-800-668-9304.
• To find locations, accessibility information, hours of operation, mammogram appointment wait times and contact information, visit Ontario Health – Wait Times.

If you live in the North West or Hamilton Niagara Haldimand Brant regions, you may be eligible for screening at one of our mobile screening coaches.

If you are First Nations, contact your doctor or nurse practitioner to learn if your travel expenses are covered through Non-Insured Health Benefits.

If you are making a mammogram appointment at an Ontario Breast Screening Program (OBSP) location you have not been to before, the location will need your past mammogram records, if you have any. You may be asked for consent (your permission) to transfer your mammogram records from the old location to the new location. To transfer your records, you will need to know the name and address of the location where you had your last mammogram. You may also sometimes be asked to bring your past mammogram records or send them in advance.

If you have been asked to bring your past mammogram records or send them in advance, call the location where you had your last mammogram and let them know you need a copy of your past mammogram records.

One of the signs of breast cancer is changes to the breast tissue, so the radiologist (the person reading your mammogram) needs to be able to compare your new mammogram to your old mammogram to see any breast tissue changes.

If you think you may be at high risk for breast cancer, talk to your doctor or nurse practitioner about a referral to the High Risk Ontario Breast Screening Program based on your family and/or medical history.

The Ontario Breast Screening Program (OBSP) is a province-wide screening program that aims to reduce breast cancer deaths through regular screening.

High Risk OBSP

High Risk OBSP sites help people who may be at high risk of getting breast cancer to undergo genetic assessment. To learn about the eligibility requirements for the High Risk OBSP, see Breast Cancer Screening for Women at High Risk.

For people who have been confirmed to be at high risk of getting breast cancer, High Risk OBSP sites offer yearly screening mammograms and breast magnetic resonance imaging (MRI) (or screening breast ultrasound if MRI is not medically appropriate).

For people with abnormal screening results, the High Risk OBSP sites coordinate follow-up breast assessments (any additional tests they need).

Ontario Health (Cancer Care Ontario) sends eligible people for the Ontario Breast Screening Program letters inviting them to get screened, informing them of their results, and reminding them when it is time to return for screening. 

Letters People May Receive

• Correspondence privacy notice
• Invitation letter
• Invitation reminder
• Recall letter (2 years)
• Recall reminder
• Normal result letter (1 year recall)
• Normal result letter (2 year recall)
• Normal result letter (no recall)

A sample of each letter type is available in the Letters to the Public area.