Breast cancer screening in Canada, 2026

Screening strategies for participants with high risk

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Individuals at high-risk have a greater lifetime risk of developing breast cancer or developing more aggressive breast cancers at an earlier age. Characteristics that make someone at high risk are defined differently across screening programs.

Nine provinces and two territories have unique criteria for managing participants identified as high-risk of developing breast cancer as part of their breast cancer programs and screening protocols vary across jurisdictions. Of the programs that manage participants identified as high-risk, mammography is the most common management strategy. Depending on the province or territory, guidelines recommend that individuals at high-risk start screening at age 30, 40 or 50 and stop at age 69 or 74.

Definitions of high-risk for breast cancer

P/T Known carrier of a deleterious gene mutation (e.g., BRCA1, BRCA2) First-degree relative of a mutation carrier (e.g., BRCA1, BRCA2) and have declined genetic testing At ≥ 25% lifetime risk of breast cancer (assessed using IBIS or BOADICEA/ CanRisk risk assessment tool) Received chest radiation before age 30 and at least 8 years previously Other
YT ✓
NT* ✓ ✓ ✓

History of chest wall radiation at age 30 or younger
  • Family history +/- germline mutation as assessed by Medical Genetics or HBOC Clinic
NU
  • Patient has had breast cancer
  • First-degree relative
  • Patient is symptomatic
BC ✓ ✓ ✓
  • Have two biological relatives (parent, child, sibling, grandparent, aunt, uncle, great-aunt, great-uncle) on the same side of the family diagnosed with breast cancer before age 50
  • Had thoracic radiation between ages 10 to 30; OR
  • Are a known pathogenic gene variant carrier or an untested family member of a known pathogenic gene variant carrier (BRCA1 or BRCA2 gene)
  • Personal history of breast cancer
  • Prior breast biopsy showing certain non-cancerous pathologies:
      • Atypical Ductal Hyperplasia (ADH)
      • Atypical Lobular Hyperplasia (ALH)
      • Classical Lobular Carcinoma In Situ (LCIS)*
  • First-degree relative (parent, child, full sibling) diagnosed with breast cancer by age 50
  • Obesity
  • Alcohol use
  • BI-RADS C (heterogeneously dense)
  • BI-RADS D (extremely dense)

(bccancer.bc.ca)
AB ✓ ✓ ✓ ✓
SK ✓ ✓ ✓
MB ✓ ✓
  • A ≥25 lifetime risk of breast cancer based on the Claus model of risk assessment
  • Confirmation of BRCA gene mutations
  • Ashkenazi decent
  •  Pathological diagnosis of ADH, ALH, LCIS
ON ✓ ✓ ✓ ✓
  • Ages 30–74*
  • No breast cancer symptoms
  • Carrier of other pathogenic or likely pathogenic gene variants (e.g., TP53, PALB2)
QC
  • Does not classify participants as high risk
NB ✓ ✓ ✓ ✓
  • Personal history of invasive cancer or pathologically confirmed DCIS
  • Individuals with highly suspected family history of breast cancer (first- or second-degree, declined genetic testing)
NS ✓ ✓ ✓ ✓
PE ✓ ✓ ✓ ✓
NL ✓ ✓ ✓
  • Participants with four second-degree relatives on the same side of the family (grandparent, aunt, uncle, niece, nephew, half sibling) with breast or ovarian cancer
  • Participants with three second-degree relatives with breast or ovarian cancer on the same side of the family with one or more of the following:
    • One person affected < 50 years of age
    • Breast and ovarian cancer in the same individual
    • Male breast cancer
  • Participants with a personal history of ovarian cancer diagnosed < 50 years of age
  • Participants who have received mediastinal radiation before 30 years of age

Data are current as of February 2026.

*Footnotes:
NT has another section of clinical practice guidelines that identifies higher-than-average risk population which includes breast density D and age +45, breast bx showing certain benign breast conditions known to increase risk (atypical hyperplasia or lobular carcinoma in situ), previous history of ductal carcinoma in situ +/- invasive breast cancer, family history of breast cancer in first-degree relative but not meeting criteria for Medical Genetics of the Hereditary Breast and Ovarian Cancer (HBOC) clinic.
ON: The High Risk Ontario Breast Screening Program (OBSP) does not accept new participants over age 70. However, when participants already in the High Risk OBSP turn 70, the program will continue to screen them with only mammography every year until they are age 74.
ADH: Atypical Ductal Hyperplasia (Atypical hyperplasia of the breast | Canadian Cancer Society)
ALH: Atypical Lobular Hyperplasia
LCIS: Lobular Carcinoma in Situ (LCIS) (Lobular carcinoma | Canadian Cancer Society)

Management of participants at high-risk by screening programs

P/T Does the program manage participants who are at high risk? Recommended screening modality Recommended age eligibility Recommended screening interval
YT ✓ Mammography (MRI in some cases) None given Annual
NT ✓ Annual clinical breast exam, mammogram and MRI and/or genetic clinic recommendations 40–74 (40 with referral from PCP, 45 can self-refer, 75+ with referral from PCP) Annual or based on radiologist recommendation
NU
BC ✓ Mammography 40–74 (75+ have the option to continue screening)

Participants aged 25 can participate in screening based on their risk. More information: bccancer.bc.ca

 Annual for those with family history or history of benign high-risk breast lesions
AB ✓ Mammography, MRI 30+ or based on provider recommendation Annual or based on medical genetics recommendation
SK* ✓ Mammography  43–74 (75+ have the option to continue screening) Ongoing annual screening available for those identified as high risk

Those identified as high risk are managed by the Saskatchewan Health Authority High Risk Screening Program
MB ✓ Mammography 50–74 (Self-referrals accepted in 45-49 and expanded to include 40-44 by 2026 end; 75+ have the option to continue screening) One to two years, depending on level of risk and radiologist recommendation
ON* ✓ Mammography and breast magnetic resonance imaging (MRI) or breast ultrasound if MRI is not medically appropriate 30–69 Annual

Ongoing annual screening for those with family history and/or documented pathology of high-risk lesions
Temporary annual screening for those with breast density ≥75% at the time of screening or based on recommendation by the radiologist at the time of screening or assessment
QC No
NB No*
NS* ✓ Mammography and breast magnetic resonance imaging (MRI) 30–74 Annual
PE ✓* Mammography 50–74 (40–49 can self-refer) Annual
NL ✓ Mammography 50–74* Annual

Data are current as of February 2026.

*Footnotes:
SK: As of July 1, 2026, eligibility age will be expanded to include women ages 40 to 42. High-risk participants are managed through the SHA High Risk Screening program. However, BreastCheck will continue to offer annual screening mammograms to any participants identified as high-risk.
ON: Participants must have no breast cancer symptoms, a valid Ontario Health Insurance Plan number, and confirmed high-risk status based on program criteria to participate in the High-Risk Ontario Breast Screening Program (OBSP). The High Risk OBSP does not accept new participants over age 70. However, when participants already in the High Risk OBSP turn 70, the program will continue to screen them with only mammography every year until they are age 74.
NB: Refer to provincial recommendations for those assessed at increased or high risk of developing breast cancer.
NS: Nova Scotia Breast Screening Program’s high-risk screening CPG has been approved.
PE: High risk patients not managed by program differently than elevated-risk patients. High-risk patients may have access to MRI if meet requirements.

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