Breast cancer screening guidelines

What Are Breast Cancer Screening Guidelines?

Cancer screening is testing done on people who may be at risk of cancer. These people have no symptoms and generally feel fine. The goal is to catch breast cancer early, when it is smallest and most treatable. In Ontario, screening mammograms are provided through the Ontario Breast Screening Program (OBSP).

Average-Risk Screening Guidelines

As of October 8, 2024, Ontario expanded self-referral access to OBSP. People ages 40 to 74 can now book a routine screening mammogram every 2 years without a doctor’s referral. This includes women, trans, non-binary, and Two-Spirit people, and women with breast implants. People over 74 can continue screening with a referral from their doctor.

High-Risk Screening Guidelines

People ages 30 to 69 who meet High-Risk OBSP criteria get screened every year. This screening includes both a mammogram and a breast MRI. Common risk factors include a known BRCA1 or BRCA2 gene mutation. Others include a strong family history of breast or ovarian cancer, or prior chest radiation before age 30. A referral into the High-Risk OBSP requires an assessment from your doctor.

Screening During Pregnancy or Breastfeeding

Screening with mammography during pregnancy is safe and effective. If you would rather not be screened while pregnant, you can wait. Start screening 3 months after giving birth, even if you are still breastfeeding. Contact your family doctor or nurse practitioner if you notice any changes in your breasts.

How to Book Your Screening Mammogram

Annex Medical Imaging is an OBSP-approved site in Toronto. Visit our Mammography & OBSP page to check your eligibility, or book an appointment directly.