Anetlanda / iStock / Getty Images Plus
It’s not surprising that rumors continue to swirl around what may or may not cause breast cancer. The disease is the second most common cancer among women (skin cancer holds the top spot), and it will take the lives of more than 40,000 women in the U.S. this year. As grim as that may be, there’s good news too: Science has debunked a lot of myths and rumors about what ups your chances for the disease, so you can stop focusing about them and concentrate on the things that really can affect your risk.
Here’s what to cross off your worry list.
Don’t sweat it, says Therese Bevers, MD, professor of clinical cancer prevention at MD Anderson Cancer Center in Houston. “There have been studies in which parabens, a substance found in antiperspirants, were also identified in breast tumors, but that doesn’t mean they caused the breast cancer,” she reports. Because parabens are widely used as preservatives in everything from shampoo to food (hence the reason these chemicals turn up in the urine of up to 99 percent of people), it’s not even clear if the parabens found in the breast tissue came from antiperspirants or from some other source. (Interestingly, according to the FDA, most brands of antiperspirants and deodorants don’t currently contain them.)
Parabens are a possible concern because studies show they have weak estrogen-like properties, and estrogen, a female hormone, causes breast cells (both normal and cancerous) to grow and divide. But so far, according to the American Cancer Society (ACS), studies have not shown any direct link between parabens and any health problems, including breast cancer. However, if you’re concerned about exposure to parabens, it’s easy to avoid them by looking for them on the ingredient lists of products.
The theory is that bras cause breast cancer by obstructing lymph flow, the means by which fluid is drained from tissues in the body and the immune cells travel to where they’re needed. But there’s no good scientific or clinical basis for this claim, reports the ACS, which notes that a 2014 study of more than 1,500 women found no association between wearing a bra and breast cancer risk.
One possible reason this myth continues to circulate has to do with body weight. As breastcancer.org explains, being overweight does increase breast cancer risk: A five-unit increase in BMI, a measure that approximates your total body fat, is associated with a 12 percent increase in risk of breast cancer in postmenopausal women. Women who are overweight are more likely to have larger breasts and wear a bra. Women who don’t wear bras, on the other hand, are more likely to be at a healthy weight.
Finally, what about putting a cell phone in your bra? “The jury is still out on that,” reports Dr. Bevers, who says more studies are needed about the connection between the non-ionizing radiation emitted by phones and breast cancer. If you’re worried, just make your bra a no-phone zone.
Either of these can lead to a hardness or thickening in the breast that, while often very concerning, is not breast cancer. Instead, what happens is the trauma causes fat in the breast tissue to change into a mass-like structure that’s like a scar, explains Dr. Bevers. The hardness may go away over time, but it often remains and—depending on the extent of the trauma—sometimes even progresses. Confusingly, “necrosis,” the technical term for this damage to the fat cells, may not appear for several years after the injury. While the “lump” it forms may feel like a cancer (Dr. Bevers admits she’s been fooled a few times with the presentation), it’s very distinctive on a mammogram and looks nothing like a breast cancer. It’s also not dangerous and doesn’t require treatment.
Having a family history of breast cancer does put you at higher risk for the disease, but it depends on the part of the tree. “I’m always more concerned about first-degree relatives, especially if they developed breast cancer before menopause, or if I see a really extensive family history,” says Dr. Bevers. “But Great Aunt Susie having breast cancer at 80 really won’t increase your risk very much.” Here’s the calculus: Having a first-degree relative (mother, sister, or daughter) with breast cancer almost doubles a woman’s risk; having two first-degree relatives increases her risk about three-fold. Overall, though, less than 15 percent of women who get breast cancer have a family history of the disease.
Soy protein has been consumed worldwide for centuries, including in Eastern cultures where the incidence of breast cancer is lower than it is in America. But the fact that natural soy foods like tofu and edamame contain isoflavones that are similar to estrogen is understandably concerning, since one risk factor for breast cancer is prolonged exposure to increased levels of estrogen in the breast tissue. According to the ACS, though, when it comes to soy, isoflavones may act like estrogen, but they have anti-estrogen properties as well. Some studies even show that people who ate soy were less likely to get breast cancer.
Dr. Bevers is cautiously optimistic about soy: “Most of the evidence suggests there’s no risk, but we need to understand it better.” Her advice is to eat soy in foods, but not excessively, and not to take any soy supplements. Indeed, the safety or benefits of these more concentrated forms of soy have not been established, so stick with eating whole or minimally processed forms of soy to reap the possible protection against cancer. Here are more fascinating health benefits of soy.
If you take or have taken birth controls pills in the recent past, you are slightly more likely to develop breast cancer than women who've never used them. But the increased risk seems to be low—25 to 30 percent from your baseline. That means that if you have a 10 percent lifetime risk of breast cancer, your baseline would increase slightly to 12.5 to 13 percent. (The average woman has a one in eight, or 12 percent chance, of developing breast cancer over an 80-year lifespan.)
The increased risk of breast cancer seems to be temporary though. According to Dr. Bevers, it appears that once a woman stops taking the pills, her risk returns to baseline within five years. This bodes well for younger women, who typically stop taking birth control pills by their early 40s, when their risk of breast cancer is very low, she says. "By the time the risk of breast cancer starts to increase, most women have been off them for five years or more and their risk returns to baseline."
Whether you’ve had (or are considering) implants to boost your bust size or to rebuild your breasts after having cancer, a host of studies show that implants don’t increase the risk of breast cancer. In fact, a few studies have found that women with implants have a lower risk of breast cancer than women without implants, although this is most likely due to traits of women who tend to choose implants, explains Susan Love, MD, a clinical professor of surgery at UCLA and author of Dr. Susan Love’s Breast Book. For instance, women with implants tend to be thinner and thus at lower risk for breast cancer.
While breast implants don’t raise the risk of breast cancer, they may slightly increase the risk of a form of lymphoma (cancer of the lymph nodes and lymphatic system) known as anaplastic large cell lymphoma, says Dr. Bevers. “But that’s very, very, very rare.”
Implants can, however, make it more difficult to see certain parts of your breast on a mammogram, since the x-rays used in mammograms cannot go through implants well enough to show the tissue under them; doctors used specialized techniques in order to maximize the amount of breast tissue they can view. “We probably don’t see 100 percent of the breast tissue that we’d see if a woman didn’t have implants, but we get the vast majority of it,” says Dr. Bevers. “There’s a tiny chance we’d miss something, but not much.”
The theoretical concern with mammograms is that the exposure to radiation is risky, but experts agree that the fear is overblown. “Mammograms are associated with one of the lowest doses of radiation exposure of all radiology tests,” explains Elisa Port, MD, chief of breast surgery at Mount Sinai Medical Center in New York City, in her book, The New Generation Breast Cancer Book. “Even when multiple pictures are taken—which happens when we perform a biopsy—the overall exposure is low, and is not associated with increased risk of cancer.” How low? According to Dr. Bevers, it’s about equivalent to the radiation a person receives flying round-trip from Texas to Paris, a trip most people wouldn’t hesitate to take.
Can’t miss your caffeine fix? Not only have most studies found no link between drinking either coffee or tea and an increased risk of breast cancer, some studies have found that women who drink a lot of caffeinated coffee have a lower risk of breast cancer compared to non-coffee drinkers. And in one 2015 study on women who were taking tamoxifen, a drug given to prevent estrogen from binding to breast cancer cells to stop them from growing and dividing, researchers found that those who had moderate (two to four cups a day) or high (five or more cups daily) coffee consumption had half the likelihood of breast cancer recurrence than those who drank less or no java.
Despite caffeine’s possible benefits to breast health, Dr. Port notes that it can promote benign breast lumps, cysts, and pain—so you may try cutting back on or avoiding caffeinated products (including coffee, tea, soda, and chocolate) all together to see if it may provide some relief from these symptoms if you’re prone to them.