MYTH: If I don’t have a family history of breast cancer, I won’t get it.
FACT: Most people diagnosed with breast cancer have no known family history.
Many people think of breast cancer as an inherited disease. But only about 5–10% of breast cancers are believed to be hereditary, meaning they’re caused by abnormal changes (or mutations) in certain genes passed from parent to child.1 The vast majority of people who get breast cancer have no family history, suggesting that other factors must be at work, such as environment and lifestyle.

But doctors often can’t explain why one person gets breast cancer and another doesn’t. The biggest risk factors are simply being a woman and growing older. Over time, healthy breast cells can develop mutations on their own, eventually turning into cancer cells.

Still, if you have a strong family history of breast cancer on either your mother’s or your father’s side, this is an important risk factor that should be taken seriously. If there are one or more cases of breast cancer in close blood relatives, especially before age 50, and/or other cancers such as ovarian and prostate cancer in your family, share this information with your doctor.

MYTH: If you maintain a healthy weight, exercise regularly, eat healthy, and limit alcohol, you don’t have to worry about breast cancer.
FACT: Although these behaviors can help lower breast cancer risk, they can’t eliminate it.

It’s something we hear again and again from newly diagnosed women: “I eat healthy, I’m at a healthy weight, I’m active, and I barely drink. So how did I end up with breast cancer?” Yes, there is evidence that all of these behaviors can help lower your risk. However, they can’t guarantee you’ll never get the disease. There are so many examples of people who do everything right and still get breast cancer.

It’s certainly worth managing the risk factors you can control, such as what you eat and drink and how physically active you are. But it’s still important to get regular screenings, perform breast self-exams, and pay attention to any unusual changes in your breasts. And if you have any “health-nut” friends or relatives who think there’s no way they’d ever get breast cancer, help them understand that no one is 100% safe.

MYTH: Wearing a bra can cause breast cancer.
FACT: There is no evidence that bras cause breast cancer.

From time to time, media coverage and the internet have fueled myths that wearing a bra can increase breast cancer risk.

The theory was that wearing a bra — especially an underwire style — could restrict the flow of lymph fluid out of the breast, causing toxic substances to build up in the tissue.

However, there is no evidence to support this claim. A 2014 study of roughly 1,500 women with breast cancer found no link between bra-wearing and breast cancer.

MYTH: Using underarm antiperspirant can cause breast cancer.
FACT: There is no evidence of a connection between underarm

antiperspirant and breast cancer, but the safety of antiperspirants is still being studied.
There have been persistent rumors that underarm antiperspirants, especially those containing aluminum and other chemicals, are absorbed into the lymph nodes and make their way into breast cells, increasing cancer risk. Shaving the underarms was thought to make this worse by creating tiny nicks that allow more of the chemicals to enter the body. Another theory was that antiperspirants, by stopping underarm sweating, can prevent the release of toxic substances from the underarm lymph nodes, also increasing cancer risk.

However, there is no evidence of a link between antiperspirant use and breast cancer. Still, some studies have found that women who use aluminum products under their arms are more likely to have higher concentrations of aluminum in breast tissue.2 If you’re concerned about minimizing the use of chemicals under your arms, check out these tips in Are Antiperspirants Safe?

MYTH: Carrying your cell phone in your bra can cause breast cancer.
FACT: There is no evidence of a connection between cell phones and breast cancer, but the safety of cell phones is still being studied.

Media reports have raised concerns that carrying a cell phone in your bra might increase breast cancer risk. There have been some cases of younger women developing breast cancer after habitually carrying their cell phones in their bras. In 2013, the Dr. Oz Show further fueled these concerns by warning women never to carry their cell phones in their bras.

The research simply isn’t there to support this claim, though. To date, most studies have focused on whether the radiofrequency radiation given off by cell phones can increase the risk of brain tumors. (This is low-energy radiation, unlike the high-energy radiation used by X-rays, for example.) This research hasn’t found a link, but the issue is still being studied.

Still, cell phone manufacturers often do recommend keeping your device away from your body as much as possible. Although there is no proven breast cancer link, you may wish to avoid wearing your cellphone in your bra or chest pocket until more research is available.

MYTH: Consuming too much sugar causes breast cancer.
FACT: There is no evidence that sugar in the diet causes breast cancer.

Not just with breast cancer but with all types of cancer, there’s a common myth that sugar can feed the cancer and speed up its growth. All cells, whether cancerous or healthy, use the sugar in the blood (called glucose) as fuel. While it’s true that cancer cells consume sugar more quickly than normal cells, there isn’t any evidence that excessive sugar consumption causes cancer.

There was a study in mice that suggested excess sugar consumption might raise the risk of breast cancer,3 but more research is needed to establish any link in animals as well as in people.

That said, we do know that eating too much sugar can lead to weight gain, and being overweight is an established risk factor for breast cancer. In addition, some studies have linked diabetes with a higher risk of breast cancer — especially more aggressive, later-stage cancers. Researchers aren’t sure if the link is due to that fact that people with diabetes tend to be overweight, or that they have higher blood sugar levels.

For health reasons, it’s always a good idea to cut down on desserts, candy, cakes, sweetened beverages, and processed foods that contain sugar. Reading labels is important, as many foods can have “hidden” added sugars like high-fructose corn syrup.

MYTH: Annual mammograms guarantee that breast cancer will be found early.
FACT: Although mammography is the best early-detection tool we have, it doesn’t always find breast cancer at an early stage.

It’s certainly normal to breathe a sigh of relief any time your mammogram comes back clean. Most women think, “I’m good for another year” and put breast cancer out of their minds.

Although mammography is a very good screening tool, it isn’t foolproof. It can return a false-negative result, meaning that the images look normal even though cancer is present. It’s estimated that mammograms miss about 20% of breast cancers at the time of screening.4 False-negative results tend to be more common in women who have dense breast tissue, which is made up of more glandular and connective tissue than fatty tissue. Younger women are more likely to have dense breasts.