Dense breasts have two risk factors: they increase your risk for breast cancer and dense breasts make it difficult for breast cancer to be seen on a mammogram. There are steps you can take to minimize your risk. Know and understand your breast density.
There are 4 categories of breast density.
Category C and D are considered “dense breasts.” Dense breasts are common and normal. In fact, about 43% of women ages 40+ have dense breasts.
The denser the breast, the higher the risk of getting breast cancer.
Having dense breasts is a more prevalent risk factor than having a family history of breast cancer.
Mammograms miss about 40% of breast cancers in the densest breasts.
Dense breasts make it harder to see cancer.
Dense breasts make it harder for radiologists to spot cancer. On a mammogram, dense breast tissue shows up as white and so does a cancerous tumour. This creates a camouflage effect.
Mammograms are a highly effective tool for women with fatty breasts, but mammograms alone are not enough for women with dense breast tissue. If you have dense breasts, you may want to discuss additional screening, such as ultrasound or MRI with your healthcare provider.
How to Find Out Your Breast Density
How can I find out my density?
Dense Breasts Canada was successful in getting breast density notification implemented on Oct.1, 2020. Anyone having a screening mammogram will be informed of their breast density category in their mammogram results letter: A, B, C, or D. Check your letter that comes in the mail.
Category C and D are dense breasts and women in these categories can benefit from additional screening.
Your healthcare provider also receives a report that has your density category.
What should I do if I have dense breasts?
1. Please discuss optimal screening for you with your provider, based on all your risk factors. Having dense breasts increases your risk, but you may have other risk factors to consider.
2.The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 20% is considered high risk. MRI is used. When using the calculator, click the word BIRADS. Category C is called heterogeneously dense and Category D is called extremely dense. (note: Alberta is the only province that considers over 20% lifetime risk for MRI).
3. Consider additional screening: The Alberta Screening Program recommendation for healthcare providers states: For women with Category D: annual mammography and consider annual breast ultrasound and annual clinical exam. Note: Experts recommend screening ultrasound or MRI for women with both Category C and D dense breasts.
Currently, these clinics have let us know that they offer screening ultrasound to women with dense breasts, paid for by Alberta Health Services:
Mayfair, Canada Diagnostics, EFW, Pureform Radiology, Central Alberta Medical Imaging Services, Beam Radiology, Calgary Women's Imaging Clinic, Insight Medical Imaging, and MIC Medical Imaging. It is your choice where to get screened.
4. Practice self-exam and consider modification of lifestyle factors.
Advocate for change in Alberta by sending them this letter.
Breast density notification was implemented only for women with Category D density in Nov. 2018. As of December 2022, anyone can learn their breast density category in one of two ways:
1. You can ask your healthcare provider; they are now told your density category or
2. Go to your MySaskHealthRecord and see your density category on the mammogram report.
Upcoming changes: The Saskatchewan screening program is updating its system to be able to notify all individuals having a screening mammogram of their breast density in the results letter mailed to them after a screening mammogram. The update will be completed in June 2025.
Additional Screening: Individuals with Category D are asked to return annually for a mammogram.
If you have Category C or D density, you have dense breasts. Please also consider requesting supplemental screening, ie. ultrasound or MRI.
Please discuss optimal screening for you with your provider, based on all your risk factors.
What is your risk?
Having dense breasts increases your risk, but you may have other risk factors to consider. The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 25% is considered high risk. MRI is used. Please click the words BIRADS when you see it and note that Category C is called heterogeneously dense and Category D is called extremely dense.
Screening at 40: Begins Jan 2025. You will be able to self-refer for a mammogram starting at age 40.
Advocate for change in Saskatchewan by sending your Health Minister this letter.
Dense Breasts Canada and patient advocates were successful in getting breast density notification implemented on Jan. 5, 2021. Anyone having a screening mammogram will be informed of their breast density category in the mammogram results letter mailed to them: A, B, C or D. Category C and D are dense breasts.
Evidence shows ultrasound or MRI are recommended for women with dense breasts as they find additional cancers that have been missed on mammogram.
Please discuss optimal screening for you with your provider, based on all your risk factors.
What is your risk?
Having dense breasts increases your risk, but you may have other risk factors to consider. The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 25% is considered high risk. Please click the words BIRADS when you see it and note that Category C is called heterogeneously dense and Category D is called extremely dense.
Advocate for change in Manitoba by sending them this letter.
Update: Dense Breasts Canada's advocacy has been successful in Ontario. All women having a screening mammogram are directly informed of their breast density in their mammogram results letter mailed to them. This began July 21, 2023. If you had a mammogram before this date, you can find out your breast density category by asking your health care provider: is it A, B, C, or D?
Category C and D are dense breasts and women with dense breasts can benefit from additional screening.
If you do not have a healthcare provider, you can call the OBSP and they will tell you your density: 1 800 668 9304
Currently, only women with Category D are asked to return annually for a mammogram, instead of every two years. However, dense breasts refer to Category C as well. Women with Category C should consider requesting additional screening, such as ultrasound or MRI. If your healthcare provider will not provide you with a requisition for additional screening, please take a look at our conversation tips in the footer of the website. There is also a clinic in downtown Toronto that offers Automated Breast Ultrasound privately.
NEWS: In December 2023 Ontario Health announced a recommendation for additional screening for individuals with Category D. The recommendation is now being implemented. You can request a MRI every 2 years or a mammogram with ultrasound every year. You need a requisition from your healthcare provider. Read more here and you can print this off for your provider too. https://www.cancercareontario.ca/en/guidelines-advice/cancer-continuum/screening/breast-density-provider-information
Please discuss optimal screening for you with your provider, based on all your risk factors.
What is your risk?
Having dense breasts increases your risk, but you may have other risk factors to consider. The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 25% is considered high risk. Please click the words BIRADS when you see it and note that Category C is called heterogeneously dense and Category D is called extremely dense.
Read our press release on breast density notification:
QUEBEC: Your mammogram report sent to your healthcare provider has a description of your density in percentages. Every report has the density. You will NOT be notified directly but you can find out your density by asking. The density information is on the third line of the report. Women with over 75% density and a family history are offered screening ultrasound.
Please discuss optimal screening for you with your provider, based on all your risk factors.
What is your risk?
Having dense breasts increases your risk, but you may have other risk factors to consider. The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 25% is considered high risk. Please click the words BIRADS when you see it and note that Category C is called heterogeneously dense and Category D is called extremely dense.
We continue to advocate for direct notification and if you would like to express your concerns about the withholding of health information, please contact The Health Minister, The Honourable Christian Dubé
ministre@msss.gouv.qc.ca
Advocate for change in Quebec by sending them this letter.
NOVA SCOTIA: Dense Breasts Canada was successful in getting breast density notification implemented in Nova Scotia October 29, 2019. Anyone having a screening mammogram will be informed of their breast density category in their mammogram results letter: A, B, C, or D. Category C and D are dense breasts.
As of 2023, individuals with Category D density are offered annual mammograms.
Please discuss optimal screening for you with your provider, based on all your risk factors.
What is your risk?
Having dense breasts increases your risk, but you may have other risk factors to consider. The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 25% is considered high risk. Please click the words BIRADS when you see it and note that Category C is called heterogeneously dense and Category D is called extremely dense.
Please note: Women with dense breasts can benefit from additional screening, such as ultrasound. However, GP requisitions for ultrasound are refused. This is the only province where this is happening. If you would like to help us advocate, please contact us at info@densebreastscanada.ca and please contact Premier Tim Houston premier@novascotia.ca to tell him that this situation is putting women's lives at risk. We also have a letter in the footer of our website.
July 2024 Letter to Premier Houston:
https://densebreastscanada.ca/wp-content/uploads/2024/07/Letter-to-Premier-Houston-July-22-2024-.pdf
Powerpoint Presentation to Nova Scotia MLAs on the need for additional screening. https://densebreastscanada.ca/wp-content/uploads/2024/02/Nova-Scotia-Presentation-The-need-for-additional-screening-for-women-with-dense-breasts-Feb-23-2024.pptx
Briefing Note: https://densebreastscanada.ca/wp-content/uploads/2024/03/Nova-Scotia-Breast-Cancer-Screening-Issues-2024.docx
NEW BRUNSWICK: Breast density notification for all women was implemented in New Brunswick in July 2020. You will be informed of your breast density category in your mammogram results letter: A, B, C, or D. Category C and D are dense breasts.
Please discuss optimal screening for you with your provider, based on all your risk factors. Women with dense breasts can benefit from additional screening, i.e. ultrasound or MRI. Read more on our Get Informed page.
What is your risk?
Having dense breasts increases your risk, but you may have other risk factors to consider. The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 25% is considered high risk. MRI is used for this category. Please click the words BIRADS when you see it and note that Category C is called heterogeneously dense and Category D is called extremely dense.
New Brunswick Breast Density Notification Press Release
PEI: Breast density notification for all women was implemented in January 2020. You will be informed of your breast density category in your mammogram results letter: A, B, C or D. Category C and D are dense breasts. Women with dense breasts can benefit from additional screening.
The government committed to screening ultrasound for women in Category D in 2018 and has not kept its commitment.
Please discuss optimal screening for you with your provider, based on all your risk factors.
What is your risk?
Having dense breasts increases your risk, but you may have other risk factors to consider. The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 25% is considered high risk and MRI is used. Please click the words BIRADS when you see it and note that Category C is called heterogeneously dense and Category D is called extremely dense.
NEWFOUNDLAND/LABRADOR:
You are not provided with any information at this time, but change is underway. Currently, your healthcare provider is notified of your density category: A, B, C or D. Women in Category D are notified in the mail and asked to return for an annual mammogram.
A software update is under way and it is expected that all women will be informed of their breast density category in their mammogram results letter: A, B, C or D as of Fall 2024.
Please check with your GP for your breast density in the interim and discuss optimal screening for you, based on all your risk factors. Women with dense breasts can benefit from additional screening.
What is your risk?
Having dense breasts increases your risk, but you may have other risk factors to consider. The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 25% is considered high risk. MRI is used. Please click the words BIRADS when you see it and note that Category C is called heterogeneously dense and Category D is called extremely dense.
How can I find out my density?
Dense Breasts Canada was successful in getting breast density notification implemented on Oct.15, 2018. Anyone having a screening mammogram will be informed of their breast density category: A, B, C, or D in their results letter. Check the letter that comes in the mail.
Category C and D are dense breasts and women in these categories can benefit from additional screening.
Your healthcare provider also receives a report that has your density category.
What should I do if I have dense breasts?
1. Please discuss the screening that best meets your needs with your provider, based on ALL your risk factors. Having dense breasts increases your risk, but you may have other risk factors to consider as well.
2.The IBIS risk calculator is recommended and can be found here When doing the risk calculator, anyone with a lifetime risk of over 25% is considered high risk. MRI is used. When using the calculator, click the word BIRADS. Category C is called "Heterogeneously dense" and Category D is called "Extremely dense."
3. Practice self-exam as mammogram accuracy is less in dense breasts. Consider modification of lifestyle factors.
4. Consider additional screening. Experts recommend ultrasound or MRI (depends on overall risk) for women with both Category C and D dense breasts. You can request a requisition from your healthcare provider.
Currently, these locations offer screening ultrasound to women with dense breasts, paid for by MSP. A requisition is needed.
Vancouver: X-ray 505. Note screening ultrasound is only available for patients who have their mammograms there.
Victoria: West Coast Medical Imaging, Fort St. for Vancouver Island residents-using Automated Breast Ultrasound
Victoria: Victoria General Hospital for Victoria residents
Prince George: University Hospital of Northern British Columbia
Vernon: Vernon Jubilee: Category D only
Kamloops: Royal Inland Hospital: Category D. Also available for Category C patients with a lifetime risk of breast cancer calculated at >20-25%.
Nainaimo: Nanaimo Regional General Hospital: MRI for Category D
Shuswap Lake: Shuswap Lake General Hospital if mammogram is done at Vernon or Salmon Arm
Port Alberni: West Coast General Hospital.
East Kootenay: East Kootenay Regional Hospital
Chilliwack: Chilliwack General Hospital: Ultrasound for Category C and D only for patients with a 1st degree relative with breast cancer or BRCA gene
This list was last updated in September 2024. Please let us know of any additional locations.
Please sign this letter to the government asking for increased access
Breast Density Notification BC Press Release
Advocate for more access to additional screening in British Columbia in by sending them this letter.
NWT: As of March 1, 2024 All women having a screening mammogram are notified of their breast density in the mammogram results letter mailed to them. Category C and D are considered to be dense breasts. Women assessed as category D density are asked to return for annual mammograms. Women with dense breasts can benefit from supplemental screening ultrasound. This is available for women with Category D density and is an official guideline from the Dept of Health.
Yukon: As of January 1, 2024: All women having a screening mammogram are notified of their breast density in the mammogram results letter mailed to them. Category C and D are considered to be dense breasts. Women assessed as category D density are asked to return for annual mammograms. Women with dense breasts can benefit from supplemental screening ultrasound, however this is not available in the Yukon at this time.
It's your health. Be breast informed.
Easily learn about your province/ territory's screening program practices, the latest research by breast cancer experts and how to advocate for the screening you need.
Accurate, current and relevant information can help you have informed conversations with your health care provider and make the best decisions for your health. Select your province/territory.
Learn about breast screening practices in your province or territory.
In May 2024, the Canadian Task Force on Preventive Health Care issued draft guidelines on breast cancer screening for women of average and moderate risk. These guidelines are used by 60,000 family doctors and nurse practitioners in their interactions with ~8 million women aged 40-74.
Here’s how the current guidelines put women’s lives at risk:
1. The guidelines do not heed expert advice: There are no breast cancer experts on the Task Force panel and no breast cancer screening experts vote on the recommendations.
2. The guidelines ignore the importance of screening for women in their 40s: 17% of cancers occur in the 40s and are more aggressive.
3. The guidelines in the past advised against breast self-exams: These exams are an important measure women can take to increase early detection of breast cancer, especially in women with dense breasts.
4. The guidelines exaggerate the harms of recalling women for additional testing after a mammogram: About 9% of women are recalled for additional images and this may cause anxiety. The Task Force considers this anxiety a harm and uses it to dissuade women from screening. The anxiety is not long lasting. Better safe than sorry.
5. The guidelines ignore significant health benefits of early cancer detection: The Task Force does not acknowledge the benefits of avoiding chemotherapy, avoiding mastectomy and avoiding lymphedema.
6. The guidelines undervalue current data: The Task Force over values outdated and flawed studies form the 1960s to 1980s. The obsolete studies estimate that women are 15% less likely to die if they have breast screening. However, current studies show a mortality benefit of 52%.
7. The guidelines do not act on the risks of breast density: Dense breasts increase the risk of developing breast cancer and increase the risk that cancer will be masked on a mammogram. The guidelines negate the benefits of supplemental screening for women with dense breasts.
8. The guidelines do not act on the earlier incidence of breast cancer in minority women: Women of race/ethnicity other than White have earlier peak age at diagnosis, higher proportions of breast cancer diagnosed under age 50, and a peak age of death younger than White.
9. Women are being asked to make decisions about life-saving screening based on inaccurate information: Using the new guidelines women may make decisions that may ultimately lead to a late diagnosis, unnecessary suffering, and a poorer prognosis.
10. The guidelines ignore the rising incidence of breast cancer in young women in Canada. in the past 34 years.
11. Women aged 40–49 in jurisdictions that do not include women in the 40s in screening programs have significantly higher proportions of stages 2, 3 and 4 breast cancer compared to their peers in screener jurisdictions.
12. Mammography screening programs for women ages 40-49 in Canada are associated with significantly higher 10-year net survival for women diagnosed with breast cancer.
13.Using The OncoSim-Breast microsimulation model (Canadian Partnership Against Cancer) to simulate a cohort of 1.53 million Canadian women born in 1975 showed that compared to no screening, screening mammography is associated with an absolute mortality reduction of 4.6 (biennial 50–74), 5.9 (biennial 40–74) and 7.9 (annual 40–74) fewer deaths per 1000 women. The absolute rate of diagnosis of advanced cancers (Stage 2, 3 and 4) falls in favor of earlier stages as the number of lifetime screens increases. https://www.mdpi.com/1718-7729/30/11/686
14 Using the OncoSim model, based on 2023 treatment standards, screening a cohort of women annually for breast cancer starting at age 40 to 74 saves the Canadian health care system $459.6M over these women’s lifetime with 3499 breast cancer deaths averted and 52367 life years gained. This translates into a savings of $1880 for every woman screened (Abstract 174) https://cslide.ctimeetingtech.com/breast24hybrid/attendee/confcal_1/presentation
15 The provinces/territories have changed their policies and are not following the CTFPHC guidelines. The provinces/ territories currently including women in their screening programs starting at 40 include BC, NS, PEI, NL, NB, and YT, and those starting at age 45 are AB and NWT. There are public commitments to lower the age to 40 in SK (2025) and ON (Fall 2024). Quebec: INESSS is reviewing the evidence. Manitoba is reviewing practices.
Canadian women and their family doctors deserve to have accurate information about the benefits of screening.