Breast Cancer Risk Factors: Ladies (and Gents), Please Read

Pink Ribbon for Breast Cancer Awareness

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Please take a few moments to familiarize yourself with the risk factors for breast cancer, the most common malignancy in women after skin cancer. Although this disease predominantly affects women, men can also develop breast cancer. The American Cancer Society predicts that of the 246,660 American women who develop new cases of invasive breast cancer in 2016, 40,450 will die from it. The statistics for men occur at about one-hundredth that rate: 2,600 and 440, respectively.

Read the companion piece, Uterine (Endometrial) Cancer Risk Factors.

Note that this post is interactive—highlighted/underscored text, images, and media contain links to external resources for further education, empowerment, and encouragement. The stories, information, and resources on this site are intended to supplement—not replace—the advice of your clinical team.

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Breast Cancer Risk Factors

The following list of breast cancer risk factors comes from Cancer Treatment Centers of America:

GENERAL

• Aging: On average, women over 60 are more likely to be diagnosed with breast cancer. Only about 10–15 percent of breast cancers occur in women younger than 45. However, this may vary for different races or ethnicities.
• Gender: Although nearly 2,300 men will be diagnosed with breast cancer each year, breast cancer is 100 times more common in women. The National Cancer Institute (NCI) estimates that over 230,000 women will be diagnosed with breast cancer annually. (Also see NCI’s Cancer Statistics and Breast Cancer Risk in American Women for more information.)

GENETICS

• Family history: Having a family history of breast cancer, particularly women with a mother, sister or daughter who has or had breast cancer, may double the risk. (However, see Breast Cancer Myths vs. Facts below about lifestyle and environmental factors.)
• Inherited factors: Some inherited genetic mutations may increase your breast cancer risks. Mutations in the BRCA1 and BRCA2 genes are the most common inherited causes. Other rare mutations may also make some women more susceptible to developing breast cancer. Gene testing reveals the presence of potential genetic problems, particularly in families that have a history of breast cancer.

– Read about Angelina Jolie’s (double mastectomy) decision based on her BRCA1 test.

BODY

• Obesity: After menopause, fat tissue may contribute to increases in estrogen levels, and high levels of estrogen may increase the risk of breast cancer. Weight gain during adulthood and excess body fat around the waist may also play a role.
• Not having children: Women who have had no children, or who were pregnant later in life (over age 35), may have a greater chance of developing breast cancer. Breast-feeding may help to lower your breast cancer risks.
• High breast density: Women with less fatty tissue and more glandular and fibrous tissue may be at higher risk for developing breast cancer than women with less dense breasts. (Also see What Happened to Diane—A Cautionary Tale for You below.)
• Certain breast changes: Certain benign (noncancerous) breast conditions may increase breast cancer risk.
• Menstrual history: Women who start menstruation at an early age (before age 12) and/or menopause at an older age (after age 55) have a slightly higher risk of breast cancer. The increase in risk may be due to a longer lifetime exposure to the hormones estrogen and progesterone.  (Also see What Happened to Diane—A Cautionary Tale for You below.)

LIFESTYLE

• A sedentary lifestyle: Physical activity in the form of regular exercise for four to seven hours a week may help to reduce breast cancer risk.
• Heavy drinking: The use of alcohol is linked to an increased risk of developing breast cancer. The risk increases with the amount of alcohol consumed.

PREVIOUS TREATMENTS

• Birth control pills: Using oral contraceptives within the past 10 years may slightly increase the risk of developing breast cancer. The risk decreases over time once the pills are stopped.
• Combined post-menopausal hormone therapy (PHT): Using combined hormone therapy after menopause increases the risk of developing breast cancer. Combined HT also increases the likelihood that the cancer may be found at a more advanced stage.
• Diethylstilbestrol (DES) exposure: Previous use of DES, a drug commonly given to pregnant women from 1940 to 1971 to prevent miscarriage, may slightly increase the risk of developing breast cancer. Women whose mothers took DES during pregnancy may also have a slightly higher risk of breast cancer.
• Radiation exposure: Women who, as children or young adults, had radiation therapy to the chest area as treatment for another cancer have a significantly increased risk for breast cancer.

Breast Cancer Myths vs. Facts

The following list of breast cancer myths and facts is available at BreastCancer.org as a slideshow:

Myth: Most breast cancers run in families.

Fact: Only 5% to 10% of breast cancers are thought to be hereditary, which means they are caused by abnormal genes passed from parent to child. The other 90% are largely due lifestyle and environmental factors. (Also see Breast Cancer Risk Factors above.)

– Listen to a podcast by Cristina Nixon, M.S., L/CGC: Genetics, Genetic Testing, and Breast Cancer (you can also download the MP3 file and a full transcript): Part 1 / Part 2 / Part 3.

Myth: There is nothing you can do to lower your risk of developing breast cancer.

Fact: Ninety percent of breast cancers are largely due to lifestyle and environmental factors. To keep your risk as low as it can be, maintain a healthy weight, exercise regularly, and limit the amount of alcohol you drink. (Also see 6 Breast Cancer Risk Factors You Can Control below.)

Myth: Bras cause breast cancer.

Fact: Underwire bras do not cause breast cancer. A 2014 scientific study looked at the link between wearing a bra and breast cancer. There was no real difference in risk between women who wore a bra and women who didn’t wear a bra.

Myth: Regular mammograms prevent breast cancer.

Fact: Mammograms don’t prevent breast cancer, but they can save lives by finding breast cancer as early as possible, when it’s most treatable.

Myth: Antiperspirants cause breast cancer.

Fact:There is no scientific evidence to support the claim that antiperspirants cause breast cancer, either because of toxin buildup or aluminum exposure.

Click to view the BreastCancer.org slideshow

Click to watch the BreastCancer.org video on YouTube

6 Breast Cancer Risk Factors You Can Control

The following list of breast cancer risk factors you can control is available at BreastCancer.org as a slideshow:

Being Overweight

Overweight and obese women—defined as having a BMI (body mass index) over 25—have a higher risk of being diagnosed with breast cancer compared to women who maintain a healthy weight, especially after menopause. Being overweight also can increase the risk of the breast cancer coming back (recurrence) in women who have had the disease. This higher risk is because fat cells make estrogen; extra fat cells mean more estrogen in the body, and estrogen can make hormone-receptor-positive breast cancers develop and grow.

(Also see more about estrogen in What Happened to Diane—A Cautionary Tale for You below—Diane has always been slender, but her breast cancer was estrogen-positive because of other factors.)

Eating Unhealthy Food

Diet is thought to be partly responsible for about 30% to 40% of all cancers. No food or diet can prevent you from getting breast cancer. But some foods can make your body the healthiest it can be and help keep your risk for breast cancer as low as possible. Research has shown that getting nutrients from a variety of foods, especially fruits, vegetables, legumes, and whole grains, can make you feel your best and give your body the energy it needs. Eating food grown without pesticides may protect against unhealthy cell changes associated with pesticide use in animal studies.

Not Exercising

Research shows a link between exercising regularly at a moderate or intense level for 4 to 7 hours per week and a lower risk of breast cancer. Exercise consumes and controls blood sugar and limits blood levels of insulin growth factor, a hormone that can affect how breast cells grow and behave. People who exercise regularly tend to be healthier and are more likely to maintain a healthy weight.

Drinking Alcohol

Compared to women who don’t drink at all, women who have three alcoholic drinks per week have a 15% higher risk of breast cancer. Experts estimate that the risk of breast cancer goes up another 10% for each additional drink a woman regularly has each day. Research consistently shows that drinking alcohol can increase levels of estrogen and other hormones associated with hormone-receptor-positive breast cancer. Alcohol also may increase breast cancer risk by damaging DNA in cells.

Smoking

Smoking causes a number of diseases and is linked to a higher risk of breast cancer in younger, pre-menopausal women. Research also has shown that there may be link between very heavy second-hand smoke exposure and breast cancer risk in post-menopausal women.

Using Hormone Replacement Therapy

Because the female hormone estrogen stimulates breast cell growth, exposure to estrogen over long periods of time, without any breaks, can increase the risk of breast cancer. Taking combination (estrogen and progesterone) hormone replacement therapy (HRT) for several years or more, or taking estrogen alone for more than 10 years, are associated with increased breast cancer risk. (Combination HRT also increases the likelihood that the cancer may be found at a more advanced stage.) (Also see more about estrogen below.)

Click to view the BreastCancer.org slideshow

What Happened to Diane—A Cautionary Tale for You

In Diane’s Story – Breast Cancer, Part 1—Chemotherapy, my friend Diane said she had two of the above-listed risk factors: “. . . late menopause put me at risk for breast cancer. Per my oncologist, all that estrogen circulating through my body each month for so many extra years was actually feeding the cancer. This and the denseness of my breasts were the only risk factors I had.”

Excess estrogen is a prime suspect in women’s cancers, including mine. See Uterine (Endometrial) Cancer – My Story & More. For more on estrogen-related risk factors for cancer, see Uterine (Endometrial) Cancer Risk Factors – Ladies (& Gents), Please Read.

In addition, Diane has dense breasts—they have more fibrous and glandular tissue than fat. This made it difficult to diagnose her invasive lobular breast cancer (ILC) and non-invasive lobular breast cancer in situ (LCIS), a process that took eight months from the day she first felt the lump in her right breast. This type of breast tumor is much less common than ductal breast cancer.

For more on Diane’s journey with breast cancer, see Breast Cancer – Diane’s Story & More.

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Resources – Breast Cancer Risk Factors

The stories, information, and resources on this site are intended to supplement—not replace—the advice of your clinical team.

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American Cancer Society

– Breast Cancer

– Breast Cancer Facts & Figures 2015–2016

– Menopausal Hormone Therapy and Cancer Risk

– What are the risk factors for breast cancer?

BreastCancer.org

– Breast Cancer Myths vs. Facts – Slideshow

– Breast Cancer Myths vs. Facts – Video

– Genetics, Genetic Testing, and Breast Cancer – Podcast by Cristina Nixon, M.S., L/CGC

• Part 1
• Part 2
• Part 3

– Having Dense Breasts

– Six (6) Breast Cancer Risk Factors You Can Control – Slideshow

– Types of Breast Cancer: 

• Invasive Ductal Carcinoma (IDC)
• Ductal Carcinoma in Situ (DCIS)
• Invasive Lobular Carcinoma (ILC)
• Lobular Carcinoma in Situ (LCIS)

Cancer Treatment Centers of America

– Angelina Jolie’s (Double Mastectomy) Decision Based on Her BRCA1 Test

– Breast Cancer Risk Factors

Centers for Disease Control and Prevention (CDC) – What Are the Risk Factors for Breast Cancer?

National Breast Cancer Foundation – Risk Factors Video

National Cancer Institute (NCI) – National Institutes of Health (NIH)

 – Breast Cancer—Patient Version

 – Breast Cancer Risk Assessment Tool

– Breast Cancer Risk in American Women

– Cancer Statistics

– Diethylstilbestrol (DES) and Cancer

Susan G. Komen®

– Breast Cancer Risk Factors Table 

– BRCA1 AND BRCA2

– Estrogen and Breast Cancer Risk

– Risk Factors and Risk Reduction

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The links for these and dozens of other sites are being compiled in Resources for Coping with Breast Cancer based on the posts on The Patient Path. Watch for updates and future posts on preventing, detecting, and treating breast and other cancers, particularly those affecting women, on this site.