Breast screening in Canada, 2023-24

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.

Eight 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 ✓ ✓ ✓
  • Confirmed mutations of BRCA1 or BRCA2 genes
  • Radiation treatment to chest area
  • First-degree family history of breast cancer
  • Personal or first-degree family history of ovarian cancer
  • Highly dense breast tissue (≥75% as shown on mammogram)
  • Personal history of breast biopsies showing ADH~
NU
  • Patient has had breast cancer
  • First-degree relative
  • Patient is symptomatic
BC ✓ ✓ ✓ Very strong family history of breast cancer: two cases of breast cancer in close female relatives on the same side of the family, both diagnosed before age 50, or three or more cases of breast cancer in close female relatives on the same side of the family, with at least one diagnosed before age 50

  • 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 (mother, sister) 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 ✓ ✓ ✓
  • ADH, ALH, LCIS~
  • Physician/radiologist recommendation
MB ✓ ✓
  • The Claus model of risk assessment
  • Confirmation of BRCA gene mutations
  • Ashkenazi decent
  • 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

*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 elevated risk? Recommended screening modality Recommended age eligibility Recommended screening interval
YT ✓ Mammography (MRI in some cases) None given Annual
NT ✓ Yellowknife Breast Screening Program (YKBSP): mammography and ultrasound, MRI in some cases

Hay River Breast Screening Program (HRBSP): mammography

 40–74 (40 with referral from PCP, 50 can self-refer, 75+ have the option to continue screening) One to two years, based on radiologist recommendation
NU – – – –
BC ✓ Mammography 40–74 (75+ have the option to continue screening)

Participants aged 30 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 30 with referral from high-risk clinic; 45–74 self-referral Annual or based on medical genetics recommendation.
SK ✓ Mammography  50–74 (75+ have the option to continue screening) Annual for those with family history and high breast density, history of benign high-risk breast lesions, or radiologist recommendation
MB ✓ Mammography 50–74 (75+ have the option to continue screening) Varies, 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 – – – –
NB No^
NS~ ✓ Mammography 50–74 Annual
PE ✓** Mammography 50–74 (40–49 can self-refer) Annual
NL ✓ Mammography 50–74** Annual

*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: Provincial recommendations for those assessed at increased or high risk of developing breast cancer were implemented in February 2022.
~NS: Nova Scotia Breast Screening Program’s high-risk screening CPG has been approved.
**NL: High-risk patients not managed by program any differently than elevated-risk patients. High-risk patients may access MRI through diagnostic services.
-NU, QC: No information was provided at the time data were collected.

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