Breast cancer risk factors, explained

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How do you know if you have an average risk or high risk for breast cancer? Find out what the risk factors are for breast cancer and how to lower your risk


By Lisa D. Curcio, MD, Breast Surgery, Nuvance Health


Breast cancer is one of the most well-known cancers. Probably because it’s the most common cancer diagnosed in women in the United States. Women are at average risk of developing breast cancer just by being a woman. Although it’s less common, men can get breast cancer.


Yet, breast cancer risk factors might not be as well known. Knowing the difference between average and high risk can help you manage it to continue savoring all the precious moments of your life.


What is the main risk factor for breast cancer?


Women have at least an average risk of developing breast cancer just by being female. The average risk of a woman developing breast cancer is about 13% in the United States. In other words, 1 in 8 women will develop breast cancer. Risk increases with age and most breast cancers occur after age 50. 


Although it is less common, breast cancer has been increasing in women younger than 50, underscoring the importance of knowing your risk.


About 1 out of every 100 breast cancers diagnosed in the United States is found in a man.



Who is at high risk of breast cancer?


You may have a greater than average risk, or high risk, of developing breast cancer from things you can and cannot change. Lifestyle things like diet and exercise can lower your risk, while family history and a genetic predisposition are things you are born with.


Breast cancer risk factors you cannot change include:


  • A strong family history of breast or ovarian cancer, including first-degree relatives (mom, sister or daughter) or multiple family members on your mom or dad’s side of the family. 


  • A personal history of breast cancer because you are more likely to develop the disease a second time.


  • A personal history of pre-cancerous breast diseases, such as atypical hyperplasia.


  • An inherited genetic predisposition to breast cancer, such as BRCA1 or BRCA2 gene mutations.

  • Dense breasts because it is harder to see tumors on a mammogram.


Your reproductive history can also influence the risk of breast cancer, including:


  • When you get your first period and menopause. Starting your period before age 12 and menopause after age 55 exposes you to hormones longer.


  • Having your first pregnancy after age 30, not breastfeeding or never having a full-term pregnancy could affect normal breast cell growth.


Other factors that could increase the risk for breast cancer that are less common include:


  • You had previous radiation therapy to the breast or chest area before age 30.


  • You took the drug diethylstilbestrol (DES) to prevent miscarriage, which was given to pregnant women in the United States from 1940 to 1971.


Breast cancer risk factors you change


Behaviors or lifestyle choices can influence breast cancer risk. Everyone can benefit from eating healthily, exercising, not drinking alcohol in excess and not smoking.


Body weight and breast cancer. Studies show a link between body weight and breast cancer. Fat cells make estrogen. Extra fat cells in the body increase estrogen levels. Estrogen fuels hormone-receptor-positive breast cancers.


Alcohol and breast cancer. Studies also show a link between alcohol and breast cancer. Alcohol also increases estrogen levels in the body. Drinking too much alcohol can also contribute to weight gain, due to the calories and sugar in alcoholic beverages and food associated with drinking. 


If you don’t want to cut out alcohol from your life, aim to drink no more than two drinks per day for men and one drink a day for women.


Diet and breast cancer. Eating healthily is super important. Following a Mediterranean, plant-based diet gives your body antioxidants and nutrients that can lower your risk of breast cancer. A healthy diet can help you manage your weight and lower your breast cancer risk. Aim to eat colorful fruits and veggies, whole grains, lean proteins (if you eat meat), fish, beans, nuts and seeds most of the time. 


Smoking and breast cancer. Please don’t smoke! Smoking increases your risk for many diseases, including breast cancer. Cigarette smoke is toxic to your body. Talk with your doctor if you need help quitting.



How to lower breast cancer risk


Remember, if you are at high risk of breast cancer that does not mean you will get it. However, it can be helpful to know your level of risk and find ways to reduce it.


All women can reduce their risk of breast cancer — and other cancers and diseases — by eating healthy, exercising, not drinking excessive alcohol and not smoking.


Please talk with your primary care provider or gynecologist because they can help you determine your breast cancer risk. They may recommend genetic counseling and seeing a breast specialist.




If you have any concerns about your breast health, you can also seek care and reassurance from a breast specialist. We can guide you through a breast cancer risk assessment and genetic counseling and testing to make decisions that fit your life.



Screenings mammograms


In addition to following these strategies to reduce your risk of breast cancer, screening mammograms are another tool you can use to take control of your health. 


Women at average risk of breast cancer should start annual screening mammograms at age 40. Your breast specialist may recommend starting sooner if you are at high risk of breast cancer. 



Screening mammograms are currently the most reliable and effective way to detect breast cancer early before it is big enough to feel or cause symptoms. 



Breast cancer risk assessment


Talk with your primary care provider or gynecologist about your breast health. They can start you on the path to determining your unique risk. They may recommend genetic counseling and seeing a breast cancer specialist for a risk assessment.


The bottom line: Knowledge is power. Knowing your risk of breast cancer may help you make changes to reduce it. Whether you have inherited risk or need help maintaining a healthy lifestyle, there are ways to manage your breast cancer risk.