There are a lot of risk factors for breast cancer, and some may surprise you.
“A lot of times, women think family history is the biggest risk factor for breast cancer,” says Dr. Rae Ann Williams, who leads the Internal Medicine Department at HealthPartners. “But the data tells us that most women who are diagnosed with breast cancer don’t have any family history of the disease.” In fact, more than 80% of breast cancer is found in women without a family history.
While there’s no way to know for sure who will get breast cancer, there are reasons you may be at greater risk to get the disease. Some risk factors you’re born with and cannot change, but other risk factors can be influenced by the choices you make. But in any case, getting your recommended breast cancer screenings can help find cancer early, when it’s most treatable.
Below, we list the top risk factors and answer the most common questions about the causes of breast cancer.
Breast cancer risk factors you can’t control
Some risk factors for breast cancer you can’t change. Having these risk factors doesn’t mean that you’ll get breast cancer, it just means that you have a higher chance of it. Although you may not always be able to control these risk factors, getting the recommended screenings can help find cancer when it’s most treatable.
Being a woman (or assigned female at birth)
Your sex is the main risk factor for developing breast cancer. If you’re a woman (or were assigned female at birth), you have a 1 in 8 chance of developing breast cancer during your lifetime – this is about 100 times higher than it is for men.
Older age
The chance of being diagnosed with breast cancer goes up as you get older. Most of the time, breast cancer is found in women who are over the age of 50. The median age for a breast cancer diagnosis is 63, which means about half of diagnoses are before that age, and about half after.
However, more women have been getting breast cancer in their 40s, which is why it’s important to start breast cancer screening by age 40 (or sooner if you have certain breast cancer risk factors).
Menstrual and reproductive history
Your risk of breast cancer is slightly higher if you got your period before age 12 or didn’t start menopause until after 55. Your risk is also slightly higher if you give birth for the first time after age 30 or if you do not give birth at all.
Family history of breast cancer or ovarian cancer
You’re more likely to get breast cancer if you have a close family member with breast cancer or ovarian cancer – this is especially true if they were diagnosed before menopause. Ask your doctor about screening recommendations if you have a family history of breast cancer.
Certain genome changes
Certain mutations in the BRCA1 or BRCA2 genes make breast cancer more likely. These mutations can cause hereditary breast cancer and may be passed down from your parents. If you have a family history of breast cancer, your doctor may recommend genetic testing.
Race and ethnicity
Breast cancer is more common in white women. However, African American and Hispanic women are more likely to have advanced breast cancer that spreads to other parts of their bodies. If you’re African American or Hispanic, ask your doctor if you should start screening sooner.
Breast density
Having dense breast tissue (a greater proportion of glandular tissue compared to fatty tissue) is normal. But having dense breast tissue does increase your risk of breast cancer. And because tumors are harder to spot among dense tissue during a screening, there’s a chance that cancer won’t be found until it’s in a later stage. You won’t know if you have dense breasts until you’ve had a mammogram. If you do have dense breast tissue, your doctor may recommend different types of breast cancer screenings or that you get screened more frequently.
Previous high-risk breast biopsy
If you’ve had a breast biopsy that showed atypical (abnormal) cells, you have a higher chance of getting breast cancer. If you’ve had an atypical biopsy, your doctor may recommend different types of breast cancer screenings or that you get screened more often.
Personal history of breast disease
If you’ve had breast cancer, you’re more likely to get it again in a different part of the same breast or in your other breast. This is why it’s important to continue screening even after breast cancer treatment.
Use of radiation or specific drugs
Having radiation to the chest increases your risk of breast cancer, especially if you had it before age 30. If you’ve had radiation to the chest, your doctor will likely recommend you start screening 5-8 years later or at 25 years old, whichever is later.
Diethylstilbestrol
If you or your mother received the drug diethylstilbestrol (DES), you have a slightly higher risk of breast cancer. This drug was used from 1940 to 1971 to prevent miscarriage.
Breast cancer risk factors you can influence
Some breast cancer risk factors can be influenced by your lifestyle and habits. By making changes, you may be able to lower your risk.
Being overweight
Being overweight increases your chance of breast cancer. But it can be hard to lose weight and keep it off since you may need to make permanent changes to your diet and activity levels. And sometimes, lifestyle changes aren’t enough to get you to a healthy weight. Talk to your primary care doctor if you’d like help with losing weight for medical reasons. They can provide helpful tips or refer you to a weight loss center, if it makes sense for you.
Drinking alcohol
Drinking alcohol increases the risk of breast cancer – as well as other cancers. And the more you drink, the more the risk increases. It’s best to not drink at all or limit yourself to one alcoholic beverage a day if you do drink.
Smoking and secondhand smoke
Tobacco use is the single largest preventable cause of cancer in the world. By quitting smoking (or never starting), you reduce your risks of numerous types of cancer, including lung, larynx, mouth, esophagus, throat, bladder, kidney, liver, stomach, pancreas, colon and rectum.
It’s also likely that quitting tobacco will reduce your risk of breast cancer. Some studies show that people who smoke for more than 10 years have a slightly increased risk of getting breast cancer, especially if they started before having their first child. It’s also possible that heavy secondhand smoke exposure increases breast cancer risk in postmenopausal women.
Low exercise levels
Exercise comes with big benefits – it can even help prevent some cancers. Just 20-40 minutes of moderate exercise a day lowers your chance of breast cancer by 6-10%, according to an American Cancer Society study. Examples of moderate exercise include brisk walking, dancing, gardening and playing tennis.
Birth control
Taking birth control pills increases your risk by about 20-30% while you’re taking them. This risk continues for about 10 years after you stop. But your chance of getting breast cancer is lower during your reproductive years, so the benefits of birth control likely outweigh the risk. If you have questions about how birth control affects your chance of breast cancer, talk to your primary care doctor. They’ll be able to provide advice that’s personalized to your situation.
Hormone therapy
Taking hormonal replacement therapy (HRT) medications that combine progesterone and estrogen for menopause symptoms increases your chance of breast cancer by about 75% while you’re on the medication. But once you stop taking the medication, your risks go down.
It’s safest not to use progesterone for menopause. But if you need relief from your symptoms, there are ways to reduce the risks of breast cancer from HRT. These options may include using estrogen-only therapy or reducing how long you take medicines that include progesterone. If you are going through menopause, talk to your doctor about how you can manage your symptoms while limiting your risks of breast cancer.
Permanent hair dye and hair straightener
A large study called the Sister Study found that women who regularly use permanent hair dye or hair straightener are more likely to develop breast cancer.
Using permanent hair dye increases breast cancer risk by 45% for African American women and 7% in white women. But the use of temporary hair color did not appear to increase risk of breast cancer.
Women who straightened their hair within 12 months of the study had an 18% higher chance of getting breast cancer. A woman’s chance of getting breast cancer also increased based on the frequency of hair straightening. For example, women who straightened their hair every 5-8 weeks had an increased risk of 31%.
So, does this mean you should quit dying and straightening your hair? Should you switch to a temporary dye? It’s really up to you, but if you have more questions or concerns, talk to your doctor.
The foods you eat
People sometimes ask if cancer is caused by eating foods such as lunch meat, cheese, sugar and fat. While it’s good to be concerned about nutrition, the truth is that specific foods aren’t generally a primary cause of breast cancer. Still, there are studies that suggest that the following foods might increase your risk:
- Dairy products. It’s unclear if eating dairy products can increase your chance of breast cancer. Some studies show increased breast cancer risk from drinking milk that includes traces of growth hormones or eating high-fat dairy products like cheese. But other studies show that the calcium and vitamin D in milk products lower cancer risk.
- Processed meats. Some studies show that eating a lot of processed meats like sausage, bacon and ham increases the relative risks of getting breast cancer.
Of course, eating an occasional cheese and bologna sandwich probably won’t increase your risks too much – assuming that your diet is generally healthy. If you’re not eating a balanced diet, it’s important to take time to improve your nutrition. Unhealthy eating can increase your chance of breast cancer in another way – being overweight is one of the top risk factors for breast cancer.
Factors that aren’t likely to cause breast cancer
In addition to breast cancer risk factors that you can and cannot control, there are also factors that you don’t really need to worry about – even if you’ve heard otherwise.
Stress doesn’t cause breast cancer
There is no evidence that high stress levels increase your chance of breast cancer. Still, managing stress is good for your overall health. So take time for activities such as deep breathing, guided imagery and exercise.
Underwire bras don’t cause breast cancer
No, wearing a bra during the day or at night does not cause breast cancer. There have been some suggestions that an underwire bra can cause cancer by draining lymph fluid from the lower part of the breast, but there’s no clinical proof to support this.
There’s no strong evidence that deodorant causes breast cancer
You may have heard that deodorants and antiperspirants containing aluminum can cause breast cancer. However, there’s no strong evidence showing this to be true.
So why do some people believe this? It has to do with how deodorants work. When aluminum is used as the active ingredient in an antiperspirant or deodorant, it forms a temporary plug in the sweat duct to prevent sweat from coming to your skin’s surface. The theory is that if the aluminum builds up in your body, it can cause estrogen-like hormonal changes that lead to breast cancer.
So, does aluminum in deodorants cause breast cancer? There hasn’t been a lot of research to prove or disprove a relationship between deodorant and breast cancer. If you’re concerned, talk to your doctor or look for a deodorant that’s aluminum-free.
It’s extremely unlikely for breast implants to cause cancer
Breast implants can cause an exceptionally rare cancer called breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL). This type of cancer affects the immune system rather than the breast.
It’s estimated that fewer than 10 people a year get BIA-ALCL. Still, if you have breast implants and notice swelling, fluid around the implant, pain, lumps, redness, or changes in the size or shape of the breast, contact your doctor right away.
The best way to reduce your breast cancer risk? Start by getting regular mammograms
The best ways to reduce your breast cancer risks are to get regular exercise, watch your weight, limit drinking and quit smoking. Most importantly, get regular mammograms, even if you don’t have any signs or symptoms of breast cancer. Often there are no visible signs in the early stages of the disease and getting regular mammograms can help catch it when it’s most treatable.
If you have questions or notice anything unusual about your breasts, make an appointment with your primary care doctor. And if you haven’t yet had a mammogram for breast cancer screening, talk to your doctor about when you should get your first mammogram – most women should start by age 40.
We offer mammograms at more than 30 locations across the Twin Cities and in western Wisconsin.