Your Risk of Breast Cancer if Your Mother Had Breast Cancer

Woman hugging her mother in the kitchen
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Having a mother with breast cancer increases the chance that you could also develop the condition. Your breast cancer risk is linked to your genetics and family history. While most breast cancer is not hereditary, it is valuable to know if you have family members who were ever diagnosed with the disease.

And a family history of breast cancer extends beyond your mother—women who have a mother, sister, or daughter who developed breast cancer at a young age (premenopausal) have double the risk of developing breast cancer when compared to women who don't have this family history.

With new genetic testing techniques, breast cancer genes can be identified even before the disease develops. Having a breast cancer gene increases your risk of getting the illness, whether you have a family history of breast cancer or not. But not all women who have a breast cancer gene will develop breast cancer, and the absence of breast cancer genes does not guarantee that you will never develop the condition—so genetic testing can be helpful, but it is not a perfect way to know if you are at risk.

Family History and Breast Cancer Risk

Breast cancer is the most common cancer among women, affecting one in eight women (12 percent) throughout their lifetimes. A family history of breast cancer can increase your likelihood of getting it.

  • A woman who has a first-degree relative (parent, sibling, or child) with breast cancer has roughly a 30 percent chance of developing breast cancer
  • A woman who has two first-degree relatives with breast cancer has five times the risk (about a 60 percent chance) of getting the disease
  • A woman who has a second-degree relative (grandparent, aunt, uncle, niece, nephew) with breast cancer has around a 22 percent chance of having the condition
  • A woman with a third-degree relative with breast cancer has around a 16 percent chance of developing breast cancer (examples of third-degree relatives include great-grandparents, cousins, or a great aunt or uncle.)
  • Prostate cancer in male relatives increases your risk of breast cancer, but the percent increase is not known

Breast cancer or prostate cancer in younger relatives (premenopausal or under the age of 50) raises your risk more than having older relatives with these conditions.

Collecting Your Family History

When it comes to learning more about your family history, it is helpful to find out if cancer has affected multiple family members, including grandparents, aunts, uncles, and cousins.

For the purpose of building your own family history, you need to know what type of cancer a relative had, what age they were diagnosed, if they were cured, still living with cancer, or have died. Other details, such as the grade, type, and stage of cancer are not as important for you to know. If you develop breast cancer, your medical team will identify your own grade, type, and stage rather than relying on your family history.

If your mother or father are alive and able to share your family's background with you, filling out the Cancer Family History Questionnaire that was created by the American Society of Clinical Oncology can help you keep track of the information. Once you gather your family history, it would be useful to keep that record for yourself and for other family members who share some of your family medical history.

Conversations About Cancer

It's also important to consider connecting with your family members by asking about more than just the facts about their illness.

How did they deal with the fear and uncertainty? Who did they lean on for support? How did they celebrate getting healthy? Let them talk about the obstacles they overcame and the things they learned about life as they fought their illness. While these conversations won't add facts about your health, they offer a valuable opportunity to bond.

Using Your Family History

You should certainly share your family history with your medical team. Your doctors might advise genetic counseling or genetic testing if your family history suggests that you could be carrying a breast cancer gene.

Some patterns that may raise red flags include:

  • If you have had cancer of any kind before the age of 50
  • More than one relative with the same type of cancer
  • One family member who has more than one type of cancer
  • A family member who has cancer not typical for that gender, such as breast cancer in a male
  • Certain combinations of cancer, such as the combination of breast cancer with ovarian cancer, uterine cancer, colon cancer, prostate cancer, pancreatic cancer, or melanoma
  • Cancer in both of one organ, for example, bilateral breast or ovarian cancer

When You Can't Find Your Family History

While many women already know if their mother, sister, or daughter have had breast cancer, you might not have this information.

If your close family members passed away at a young age, if some of them didn't have access to health care (and might not have been diagnosed), or if members of your family have been separated, you might not know which illnesses run in your family. Of course, you also may not have access to your family history if you were adopted.

Rest assured that it is perfectly fine to have gaps in your family health history. Breast cancer screening with mammograms and breast self-examinations are the most important tools for early detection, whether or not you have a family history of the disease.

Genetic Testing

Your family history is a record of the diseases that your family members were diagnosed with. Genetic testing is a bit different. You could have inherited a gene for breast cancer even if no one in your family ever had the disease. And you could have a hereditary tendency to develop the condition even if you don't have an identifiable breast cancer gene.

There are a number of genes associated with breast cancer. The most common of these are BRCA1 and BRCA2 mutations, but there are over 70 identified gene mutations associated with breast cancer, some of which are described as non-BRCA gene mutations. And there is a link between breast cancer genes and the outcome of the disease.

Genetic testing requires a complex decision-making process. The genes you should be tested for and the overall value of the test depend on a number of factors, including your age, health history, family history, race, and ethnic background. For example, an at-home genetic test identifies breast cancer genes that are more common among Ashkenazi women but are rare in other ethnic populations.

Genomic testing and whole exome sequencing are genetic tests that can provide you with information about all of your genes, not just breast cancer genes. This type of testing can be useful, but the cost might not be covered by your health insurer and "good" results can provide a false sense of security—you can develop breast cancer even if you don't have a known breast cancer gene.

A Word From Verywell

Whether you have a family history of breast cancer or not, there are ways for you to lower your own risk. Make sure that your healthcare team knows if your mother, sister, daughter, or other family members had this disease or if you or any of your relatives carries a gene for the disease. And definitely, don't skip your annual screenings.

More and more women and men are getting diagnosed with breast cancer at an earlier stage, receiving more effective treatment, and surviving for years after the diagnosis. You certainly need to be vigilant if you have a family history of breast cancer, but there is no need to live in fear.

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