Breast cancer screening in Canada 20xx-20xx
Breast screening for individuals at elevated and high risk
Learn more about:
- plans to implement risk-based breast cancer screening
- definitions of elevated risk for breast cancer
- management of participants at elevated risk by screening programs
- definition and data collection for high breast density by screening programs
- data collection of breast density (map)
- definitions of high risk for breast cancer
- management of participants at high risk by screening programs
Individuals at elevated risk are those who are considered to have a greater than average risk for developing breast cancer, but a risk level less than the highest risk group. This may include people who have a family history of breast cancer, have high breast density, used hormone replacement therapy in the past, or are at high risk for benign breast disease. This differs from individuals at high risk who have a greater lifetime risk of developing breast cancer or developing more aggressive breast cancers at an earlier age due to specific factors (e.g., genetics).
Ten provincial/territorial breast screening programs manage participants at elevated risk of developing breast cancer. Some provincial and territorial screening programs define elevated risk as having first-degree family history of breast cancer, using hormone replacement therapy, having a breast density of equal to or over 75%, having a history of high-risk benign breast disease, and having a recommendation by a radiologist. Other provincial and territorial breast screening programs only have one to four of these characteristics listed to define elevated risk. Other characteristics that are listed as risk factors include: having personal or first-degree family history of ovarian cancer, having a first-degree male relative with breast cancer, three or more second-degree family history of breast or ovarian cancer, and documented pathology of high-risk lesions. QC and NB do not classify participants as elevated risk of developing breast cancer. Individuals who are found to be at elevated risk of developing breast cancer are in most cases screened annually with a mammogram, starting at age 40 or 50.
Plans to implement risk-based breast cancer screening
Jurisdiction | Plans to implement risk-based breast cancer screening? (✓) | What approaches are being taken to identify high-risk individuals? | What activities are being done to support risk-based screening? |
---|---|---|---|
YT | |||
NT | |||
NU | |||
BC | |||
AB | |||
SK | |||
MB | |||
ON | |||
QC | |||
NB | |||
NS | |||
PE | |||
NL |
Definitions of elevated risk for breast cancer
Jurisdiction | First-degree family history (✓) | Hormone replacement therapy (✓) | Breast density > or ≥ 75% (✓) | History of high-risk benign breast disease (✓) | Radiologist recommend-ations(✓) | Other |
---|---|---|---|---|---|---|
YT | ✓ | ✓^ | ✓ | |||
NT | ✓ | ✓ | ✓ | ✓ | ✓ | · Personal history of breast cancer · Personal history of other cancer (i.e. ovarian cancer) · 3 or more second-degree family history (breast or ovarian) |
NU* | ✓ | ✓ | ✓ | |||
BC | ✓ | ✓ | ||||
AB | ✓ | ✓ | ✓ | ✓ | ||
SK | ✓ | ✓ | ✓ | · Personal history of breast cancer · Personal history of other cancer |
||
MB | ✓ | ✓ | ✓ | · At least one 1st or 2nd degree female relative on either maternal or paternal side of the family with a history of breast or ovarian cancer that does not fall into the high increased risk category · Ashkenazi decent |
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ON | ✓ | ✓ | ✓ | · Personal or first-degree family history of ovarian cancer · First-degree male relative with breast cancer · Two or more first-degree female relatives with breast cancer at any age, or one under age 50 · Documented pathology of high-risk lesions |
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QC | Does not classify participants as high risk | |||||
NB | Does not classify participants as high risk | |||||
NS | ✓ | ✓ | ✓ | ✓ | ||
PE | ✓ | ✓ | ✓ | ✓ | ||
NL | ✓ | ✓ | ✓ | · Women with four second degree relatives on the same side of the family (grandparent, aunt, uncle, niece, nephew, half sibling with breast or ovarian cancer) · Women with three second degree relatives with breast or ovarian cancer on the same side of the family with one or more of the following: o One person affected < 50 years of age o Breast and ovarian cancer in the same individual o Male breast cancer · Women with a personal history of ovarian cancer diagnosed < 50 years of age · Women who have received mediastinal radiation before 30 years of age · Women who have been assessed by genetics and confirmed to be at a high risk of breast cancer |
*Information for NU in this publication refers to opportunistic breast screening.
^ Applies to women who receive a ‘D’ breast density score (BI-RADs category D- extremely dense >75% glandular)
Management of participants at elevated risk by screening programs
Jurisdiction | Does the program management participants who are at elevated risk? (✓) | Recommended screening modality | Recommended start age | Recommended interval | Recommended stop age |
---|---|---|---|---|---|
YT | ✓ | Mammography | None given | Annual | None given |
NT | ✓ | YKBSP: mammography and ultrasound, MRI in some cases HRBSP: mammography |
40 (40 with referral from PCP, 50 self-referral) |
1-2 years, based on radiologist recommendation | 74 (75+ have the option to continue screening) |
NU* | ✓ (Referred to diagnostic centre) |
50 | 74 | ||
BC | ✓ | Mammography | 40 | Annual for those with family history or history of benign high-risk breast lesions | 74 |
AB | |||||
SK | ✓ | Mammography | 40 | Annual for those with family history and high breast density | 74 (75+ have the option to continue screening) |
MB | ✓ | Mammography | 50 | Varies depending on level of risk and radiologist recommendation | 74 (75+ have the option to continue screening) |
ON^ | ✓ | Mammography | 50 | Ongoing annually for those with family history and/or documented pathology of high-risk lesions | 74 |
QC | |||||
NB | |||||
NS | ✓ | Mammography | 50 (40-49 can self-refer) |
Annual | 74 |
PE | ✓ | Mammography | 40 | Annual | 74 |
NL | ✓ | Mammography | 50~ | Annual | 74~ |
* Information for NU in this publication refers to opportunistic breast screening.
^ The OBSP does not use the term “elevated risk”, however, there are several reasons a woman in the OBSP will be recalled by the program in one year: documented pathology of high risk lesions; a personal history of ovarian cancer; two or more first-degree female relatives with breast cancer at any age; one first-degree female relative with breast cancer under age 50; one first-degree relative with ovarian cancer at any age; one male relative with breast cancer at any age; breast density ≥75 percent at the time of screening; or recommendation by the radiologist at the time of screening or assessment
~ Start/stop age is variable depending on conditions for elevated risk designation (e.g. breast density ≥75% may be a transitory condition, therefore start/stop age would be adjusted)
– No information was provided at the time the data were collected.
Evidence shows that individuals with dense breasts have an increased risk of developing breast cancer, and that having dense breasts can make it more difficult to detect breast cancer by mammogram alone.8 What is not clear, however, is whether more frequent mammographic screening or ‘supplemental screening’ with ultrasound or MRI improves outcomes for these people.7
In Canada, some jurisdictions classify individuals with high breast density as being at elevated risk and, consequently, these individuals are, in most cases, eligible for more frequent screening. Most of these jurisdictions define high breast density as ≥ 75% glandular tissue.
Ten provincial/territorial breast screening programs collect information on breast density. In ON and SK, individuals who have dense breasts receive a breast density fact sheet with their mammography results. Participants are also notified that their next mammogram will be in a year due to dense breast tissue. MB and NL advise individuals of their breast density in the result letter. BC also notifies participants of their breast density. NS began advising individuals of their breast density in their results letter starting in fall 2019, as well as including a breast density fact sheet alongside all results letters.
Definition and data collection for high breast density by screening programs
Jurisdiction | Definition of high breast density | Does the program collect information on breast density (✓) | Does the program recommend more frequent screening for those with high breast density? (✓) | Are participants notified of their breast density? (✓) Yes | Are participants notified of their breast density? (✓) No | If participants are not notified of their breast density, are there any plans to send out notifications? |
---|---|---|---|---|---|---|
YT | BI-RADS^ category D | ✓ | ✓ (Participants can request information from their PCP; all screening reports include density information) |
Not at this time | ||
NT | ≥ 75% glandular tissue | ✓ | ✓ | ✓ (Documented on mammogram report to PCP) |
No | |
NU* | ✓ | |||||
BC | BI-RADS^~ | ✓ | ✓ (They receive their BI-RADS breast density assessment with their results and an informational brochure) |
|||
AB | ≥ 75% glandular tissue | ✓ | ✓ (Women can request information from their PCP as all screening radiology reports density information) |
Program is working on a comprehensive plan to address density including provision of risk information to women & PCP, standardized reporting and appropriate supplemental exams recommendations. | ||
SK | ≥ 75% glandular tissue | ✓ | ✓ | ✓** (Approximately one week after their mammogram they receive a letter informing them that they have breast density along with a recommendation to screen annually and an information leaflet about breast density) |
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MB | ≥ 75% glandular tissue | ✓ | ✓ (Breast density is reported on the patient and PCP result letter, indicated as <75% or ≥75% (extremely dense)) |
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ON | ≥ 75% glandular tissue | ✓ | ✓‡ (Participant receives a screening result letter accompanied by a breast density fact sheet. The letter will inform the participant that their next mammogram should be in one year due to dense breast (greater than or equal to 75%) tissue as seen on their mammogram.) |
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QC | ≥ 75% glandular tissue | ✓ | ✓ (PCP receives report with breast density. PCP can inform the patient.) |
No | ||
NB | Adoption of BI-RADS^ classification in progress; will be C or D | ✓ (however only if categorized as < or > 50%; data is not consistently submitted) |
Recommendations for the management of High Breast Density are under planning and development; Currently supplemental screening is based on Radiologist recommendations | ✓ (Currently, participants can request their breast density results according to RHA data request processes) |
Recommendations are in progress to include breast density results on all radiology reports so that PCPs can inform women of their breast density results | |
NS | Category C (heterogeneously dense) or Category D: (extremely dense) | ✓ | Radiologist can recommend more frequent breast screening. | ✓ (Starting in Fall 2019, women are notified of their breast density (BI-RADS category) in their screening results letter, accompanied by a breast density fact sheet) |
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PE | ≥ 75% glandular tissue | ✓ | ✓ (Participant receives a screening result letter with the breast density and a density fact sheet as of January 2020. Prior to 2020, the PCP was notified of breast density information.) |
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NL | ≥ 75% glandular tissue | ✓ | ✓ | ✓ (Patient are told in results letter that their screening interval is 12 months due to the nature of their breast tissue) |
* Information for NU in this publication refers to opportunistic breast screening.
^ Breast Imaging and Reporting Data System (BI-RADS) categories for breast density: A- almost entirely fatty (<25% glandular); B- scattered fibroglandular densities (25-50% glandular); C- heterogeneously dense (51-75% glandular); D- extremely dense (>75% glandular).
~ BC radiologists categorize breast composition using BI-RADS to assess the volume of breast density. The C and D categories are commonly referred to as “dense”. BC Breast Screening currently provides BI-RADS assessment for women and providers; however, it has no definition for “high breast density”.
**Informed that they have dense breasts, but not informed what their dense percentage is
‡Only participants with normal results who have dense breasts, as defined by the program, are informed
– No information was provided at the time the data were collected.
Individuals at high risk have a greater lifetime risk of developing breast cancer or developing more aggressive breast cancers at an earlier age. Currently, there are no national guidelines for screening individuals at high risk and screening protocols vary across jurisdictions. The definition of high risk of developing breast cancer also varies across Canada.
Definitions of high risk for breast cancer
Jurisdiction | 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 risk assessment tool) (✓) | Received chest radiation before age 30 and at least 8 years previously (✓) | Other |
---|---|---|---|---|---|
YT | Does not classify participants as high risk | ||||
NT | ✓ | ✓ | ✓ | ||
NU | ✓ | ✓ | ✓ | ✓ | |
BC | ✓ | ✓ | ✓ | ✓ | · Very strong family history of breast cancer: 2 cases of breast cancer in close female relatives on the same side of the family, both diagnosed before age 30, or 3 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 |
AB | ✓ | ✓ | ✓ | ✓ | · Ashkenazi decent · ADH, ALH, LCIS |
SK | · Abnormal mammograms · Breast density · ADH, LCIS · physician/radiologist request |
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MB | ✓ | ✓ | · The ‘Claus model’ of risk assessment · Ashkenazi decent · ADH, ALH, LCIS |
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ON | ✓ | ✓ | ✓ | ✓ | · Ages 30-74 · No acute breast symptoms · Deleterious gene mutations that confer higher risk of breast cancer (e.g., TP53, PTEN, CDH1) |
QC | Does not classify participants as high risk | ||||
NB | Does not classify participants as high risk | ||||
NS | ✓ | ✓ | ✓ | ✓ | |
PE | ✓ | ✓ | ✓ | ✓ | |
NL | ✓ | ✓ | ✓ |
* Information for NU in this publication refers to opportunistic breast screening.
Abbreviations: Atypical Ductal Hyperplasia (ADH)^, Atypical Lobular Hyperplasia (ALH)^, and Lobular Carcinoma in Situ (LCIS)~
^ https://www.cancer.org/cancer/breast-cancer/non-cancerous-breast-conditions/hyperplasia-of-the-breast-ductal-or-lobular.html
~ https://www.cancer.org/cancer/breast-cancer/non-cancerous-breast-conditions/lobular-carcinoma-in-situ.html
Six provincial/territorial breast screening programs manage participants identified as high risk of developing breast cancer. Their management strategies include recommending mammography, MRI and/or ultrasound screening. Some programs do not manage high-risk participants directly but refer those individuals to a high-risk program or clinic. 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.
Management of participants at high risk by screening programs
Jurisdiction | Does the program manage participant who are high risk (✓) | How are high risk participants managed? | Recommended screening modality for high risk | Recommended start age for high risk | Recommended interval for high risk | Recommended stop age for high risk |
---|---|---|---|---|---|---|
YT | N/A | N/A | N/A | N/A | ||
NT | ✓ | Mammography only other modalities managed by PCP | YKBSP: mammography and ultrasound; MRI in some cases HRBSP: mammography |
40 | Based on radiologist recommendation | 74 |
NU* | ✓ | Referred to diagnostic centre | Mammography | Varies | 74 | |
BC | Eligible for annual routine screening, but no supplemental screening, referred to high risk clinic | Mammography | 40 | Annual | 74 | |
AB | Managed by PCP or high risk clinics | Mammography & screening breast MRI | No earlier than 25 and no later than 40 | Annual | 74 | |
SK | N/A | N/A | N/A | N/A | ||
MB | ✓ | Recalled for routine screening | Mammography | 50 | Annual (can vary) Or as per radiologist recommendations |
74 (75+ have option to continue screening |
ON^ | ✓ | Referred to the High Risk OBSP | 30-69: Mammography and MRI (or ultrasound if MRI is not medically appropriate) 70-74: Mammography only |
30 | Annual | 74 |
QC | N/A | N/A | N/A | N/A | ||
NB | Currently managed by radiologist | N/A | N/A | N/A | N/A | |
NS~ | ✓ | Eligible for annual screening mammography and screening breast MRI. Annual requisitions for MRI required. | Screening Mammography and MRI spaced 30 days apart | 30 | Annual | 74 |
PE | ✓ | Annual screening (referral from PCP is required) |
Mammography and MRI | 40 (or as recommended by a radiologist) |
Annual | 74 |
NL | Eligible for annual routine screening, but no supplemental screening, PCP may order supplemental testing – MRI | N/A | N/A | N/A | N/A |