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Know Your Risks for Breast Cancer

Personal health · Oct 13, 2021

We've all heard the sobering stats: about 1 in 8 women will develop breast cancer in her lifetime.1 First off we can't talk about the latest on breast cancer risk without first talking about screening and some of its limitations because evidence shows that early detection via mammography can help save lives before cancer has spread.

The benefits of having a mammogram

Mammograms can usually find lumps two or three years before a doctor or self examination. Early detection can offer a better chance of cure and can avoid the adverse effects of treatments for more advanced disease.

The concerns

A False Negative

Cancer could be missed, especially in women under the age of 50. Younger breast tissue can be dense, making abnormalities more difficult to detect. Knowing your own breast density (more on this below) and tissue texture with intermittent self checks can help mitigate this risk.

False Positive

There is the possibility of detecting breast cancer and then having unnecessary treatment for something that may never have caused problems. However, science is not yet at a point to unequivocally know which cancers are “safe” to leave alone and which ones need treatment.

Exposure to Radiation

There is exposure to low levels of radiation with mammography; for a screening mammogram of both breasts the dose of radiation is about the same amount as that for a woman to receive from her natural surroundings over about 7 weeks.2

The latest: breast density matters - be informed

“Dense” breasts contain more connective tissue than fat. This can make it more difficult to detect breast cancer on a mammogram. Further, breast density itself is a risk factor for breast cancer. Studies have found that people with dense breasts are 4-6 times more likely to develop breast cancer than women with the least dense breasts.3 Importantly, dense breasts seen on mammograms are independent of how breasts look or feel.

Dense breasts are normal and common. For women aged 40-74 years, 43% have dense breasts.4 Breasts usually become less dense and more fatty with age:

Hormone replacement therapy can increase breast density. Alcohol use can also increase breast density as well as overall breast cancer risk.

Advocacy groups in North America are lobbying screening programs to disclose breast density to mammogram recipients. Still not all provinces in Canada routinely report breast density.

How to find your breast density in your province

Up to date information can be found at Dense Breasts Canada. Dense Breasts Canada is also lobbying for access to ultrasounds for women in the highest density categories.

Steps you can take to help lower your breast cancer risk

Know your own risk. The National Cancer Institute (NCI) website has an interactive breast cancer risk assessment tool that can help you and your health professional determine your individual risk of invasive breast cancer.

In addition, you can make lifestyle choices that can help keep your risk as low as it can be:

  • maintaining a healthy weight

  • get regularly exercise

  • limiting alcohol

    • During this pandemic, folks have increased their alcohol intake. All types of alcohol counts. Worrisomely, we know that women who have three alcoholic drinks per week have a 15% higher risk of breast cancer when compared to women who don't drink at all.5 That goes up another 10% for each additional drink women regularly have each day.

  • eat healthily

  • never smoking, or quitting if you are a current smoker

For more information on your risks for breast cancer, see the Canadian Cancer society site.


1. The American Cancer Society. (2021, 7 mai). How Common Is Breast Cancer.

2. The American Cancer Society. (2020, 5 mars). Mammogram Basics.

3. Dense Breast Info.

4. Breast Density Canada. Sprague BL, Gangnon RE, Burt V, et al. (2014). Prevalence of mammographically dense breasts in the United States. J Natl Cancer Inst, 106(10), dju255.

5. (2021, 21 avril). Drinking Alcohol.,higher%20risk%20of%20breast%20cancer

Authored by:
Dr. Rhonda Low
Family physician, TELUS Health Care Centres

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