Good question: Can you prevent breast cancer?

Breast cancer is the most commonly diagnosed cancer among women in Canada, accounting for approximately one-quarter of all new cancer cases.¹ For many people, that raises an important question: Can breast cancer be prevented?

The answer is not entirely straightforward.  Breast cancer risk is shaped by biology, lifestyle, and environmental exposures. Some factors can be changed and others cannot.

We asked Dr. Sonal Gandhi, a medical oncologist and member of the advisory services team at Cleveland Clinic Canada, which serves as Medical Director for Manulife Group Benefits, to help explain what’s known, what’s less clear, and where prevention fits into the picture.

Breast cancer cannot be fully prevented. While many factors beyond a person’s control strongly influence whether they will develop breast cancer, some lifestyle factors can help reduce the risk.

The two strongest risk factors for developing breast cancer are being female and getting older. Family history can also increase risk, although most breast cancers are not linked to a known inherited genetic change.² Having a family history of breast cancer does not mean you will necessarily develop it.

Some risk factors can be influenced by the choices we make. Maintaining a healthy weight, avoiding smoking, limiting or eliminating alcohol, and staying physically active may all help reduce breast cancer risk. However, reducing risk is not the same as eliminating it entirely.

Screening, which means testing for cancer before symptoms appear, plays a different role. It does not reduce the risk of developing breast cancer, but it can help find cancer earlier.

The impact of lifestyle choices will differ from person to person because everyone has a different baseline risk, influenced by factors such as age, family history, breast density, and hormonal history.

Many of these factors cannot be changed, while others involve complex personal or medical decisions. For example, the timing of pregnancy and whether someone has breastfed may influence breast cancer risk.³  Most people, however, do not make reproductive decisions based on reducing their breast cancer risk.

The step-by-step self-examinations women were once taught are no longer routinely recommended because research has not shown that they improve breast cancer outcomes⁴. They can also lead to false alarms and unnecessary testing.

Instead, experts encourage women to be "breast aware" by becoming familiar with how their breasts normally look and feel. This can help them recognize changes that may warrant medical attention.

Mammograms are the main screening test for breast cancer for people at average risk. They can help detect breast cancer early, when it may be easier to treat.

For people at average risk, screening recommendations vary across Canada. Depending on where they live, routine mammograms may begin between ages 40 and 50 and generally continue until age 74. People at higher risk may be advised to begin screening earlier or have additional screening.

In general, younger women tend to have denser breast tissue, which can make mammograms more difficult to interpret. This may lead to more false-positive results, additional testing, and biopsies that ultimately show no cancer is present.  Screening recommendations are designed to balance the benefits of early detection with the potential harms of unnecessary testing, which is why routine mammograms are not generally recommended for women under 40 at average risk.

That said, anyone who notices changes in their breasts should speak with a healthcare provider, who can determine whether other testing is needed, regardless of whether they are eligible for routine screening.

Genetic testing can help identify individuals at particularly high risk.

A strong personal or family history of certain cancers may prompt a conversation with a healthcare provider, who can help assess a person’s risk by reviewing their personal and family history and, when appropriate, referring them for genetic counselling or testing. However, having a family history of breast cancer does not necessarily mean you carry a genetic mutation.

Women considered high risk may be advised to supplement mammograms with breast MRI, particularly at younger ages when breast tissue is denser.

You may not be able to change every risk factor, but you can take meaningful steps to help lower your risk and optimize your general health as well. Understanding your personal risk can help you make informed lifestyle choices and determine, with guidance from your healthcare provider, when to begin screening. Lifestyle choices may help lower your breast cancer risk, while screening can support earlier detection.

^{This article is for informational purposes only. It is not intended to diagnose or treat a condition. If you have questions or concerns about your specific situation or are seeking medical advice, contact your medical doctor or your healthcare provider.}

^{Cleveland Clinic Canada}

^{Manulife is proud to have Cleveland Clinic Canada on board as Medical Director for our Group Benefits operations. Cleveland Clinic Canada has a wealth of global healthcare expertise and shares our goal to help Canadians live longer, healthier, and better lives. Cleveland Clinic is a nonprofit organization that has been at the forefront of modern medicine since 1921. In recent years, Cleveland Clinic has worked with progressive companies in Canada and around the world to prioritize the health and well – being of their employees, customers, and communities.}