So many rumors and controversies surround breast cancer—what really causes it, what really prevents it—that it can be hard to know whom to believe. Just because a friend swears that wearing a bra can cause breast cancer doesn't mean it's true. And if you think that you're not at risk because there's no breast cancer in your family, you might be mistaken. The truth is that scientists still don't know what causes breast cancer—only that certain factors, such as obesity or drinking too much alcohol—may increase risk.
That's why Prevention has teamed up with a new organization called the Love/Avon Army of Women, whose mission is to help scientists better understand what causes breast cancer so we can prevent it once and for all. Learn more about this amazing initiative here, and then read on to separate breast cancer fact from fiction.
Myth: Breast cancer is largely genetic. Fact: Just 5 to 10% of cases are due to faulty breast cancer genes BRCA1 and BRCA2.
Even in women who have a family history, many cases are due not to specific gene mutations, according to the American Cancer Society, but, rather, to a combination of shared lifestyle factors and genetic susceptibilities. The truth is that scientists still have no idea what causes breast cancer. But one of the best ways to find out is to compare women who've never had it with those who have or who face an increased risk—the type of research the Army of Women hopes to contribute to.
Myth: Small-chested women have a lower risk. Fact: Your bra size doesn't play a role in whether or not you get breast cancer. All breast cancers develop in the cells that line the ducts or lobules—the parts that make milk and carry it to the nipple—and all women have the same number of these, regardless of breast size. What makes breasts bigger or smaller is generally the amount of fat and stroma (fibrous tissue), which research shows have little impact on cancer odds. Bottom line: All women 40 and older need regular mammograms.
Myth: Breast cancer always appears as a lump. Fact: Approximately 10% of those diagnosed with breast cancer have no lumps, pain, or other indications of a problem in their breasts. And among lumps that are detected, 80 to 85% are benign. They're often cysts or noncancerous tumors called fibroadenomas. That said, any lump or breast symptom (especially from the list below) that does not go away should be checked by a doctor.
A change in how the breast or nipple feels or looks
A lump or thickening in or near the breast or in the underarm area
Breast pain or nipple tenderness
A change in the size or shape of the breast
A nipple or skin that turns inward into the breast
Feeling warm to the touch
Scaly, red, or swollen skin of the breast, areola, or nipple, perhaps with ridges or pitting that resembles an orange peel
Myth: Mammograms prevent or reduce your risk. Fact: Regular mammograms will not prevent or reduce your risk of breast cancer. They just detect breast cancer that already exists—reducing deaths among breast cancer patients by about 16%. However, most breast cancers have been present for 6 to 8 years by the time they appear on mammograms, and screening misses up to 20% of all tumors. That's why it's important that all women have an annual breast exam performed by a health care provider and pay close attention to their own bodies to spot potential changes as early as possible. Getting a high-quality mammogram and having a clinical breast exam on a regular basis are the most effective ways to detect breast cancer in its earliest stages, but we still need more information about how women can prevent it in the first place—which is where the Army of Women plays an important role.
Myth: Mammograms cause breast cancer. Fact: The risk of harm from radiation is minuscule compared to the huge benefits of early detection. The ACS recommends that women 40 and older have a mammogram every year. Radiation doses are regulated by the FDA and are fairly low—equivalent to the amount the average person receives from naturally occurring sources over 3 months. Also, women today receive 50 times less radiation from mammograms than they did 20 years ago, with the risk of long-term health effects being almost zero, according to the FDA. As each case of breast cancer is different, every woman should talk with her doctor about her personal risk factors for breast cancer. Those at high risk may need to start getting mammograms before age 40 or couple them with more sensitive screening methods, like MRI.
Myth: Birth control pills cause breast cancer. Fact: Doctors say the evidence isn't strong enough for them to recommend that women stop taking birth control pills to avoid breast cancer. Some studies from the mid '90s showed that birth control users had a slightly increased risk, but researchers caution that pill formulations have changed since then (most contain much lower doses of the hormones linked to breast cancer risk). This research also found that the risk returned to normal 10 years after women stopped taking the pills. Some research suggests that risk may depend on ethnicity or age (African-Americans and those who take pills after age 45 have a slightly increased risk), while other studies found no association between pills and cancer whatsoever. "This suggests that birth control-related breast cancer risk may not be the same for all women," says Susan Love, MD, a breast cancer surgeon and founder of the Army of Women, "which is why we need the Army of Women to help figure out whether subgroups have different risks."
Myth: Young women don't get breast cancer. Fact: While it's true the disease is more common in postmenopausal women, breast cancer can affect people of any age. In fact, women under 50 account for 25% of all breast cancer cases, and they tend to have higher mortality rates. This may be partly explained by the fact that younger women tend to have denser breasts, which makes it harder to spot lumps during mammograms. Because of this, it's a good idea to perform monthly self breast exams starting at age 20, have a clinical exam by a doctor every 3 years, and start mammographic screening at age 40. If you have a family history of breast cancer, ask your doctor about also getting a breast MRI: Younger women who get breast cancer are more likely to have a mutation in the BRCA 1 or 2 genes than older women are, and one study found that MRI picked up 77% of cancers in these women, compared with 36% by mammography. If your doctor says you have dense breasts, request a digital mammogram, which found 15% more cancers than standard mammograms in women under 50 and 11% more in women with dense breasts in a 2005 study.
Myth: Deodorant and antiperspirants cause breast cancer. Fact: Skipping these toiletries won't keep your breasts cancer free. One email rumor claimed that antiperspirant prevents you from sweating out toxins, which can then accumulate in the lymph nodes and cause breast cancer. But in 2002, researchers at the Fred Hutchinson Cancer Research Center in Seattle conducted a study to address this rumor—and found no link between deodorant or antiperspirant and breast cancer. A second rumor speculated that certain chemicals in antiperspirants, such as aluminum and parabens, may cause breast cancer because there is a lower prevalence of the disease in developing countries where women don't use these products. However, toxins are not usually released through sweat, and in Europe, where antiperspirants are not widely used, the rate of breast cancer is higher than it is in the United States. Finally, although a 2004 study found parabens in the tissue of breast cancer tumors, so far no studies have shown that these or any other chemicals in deodorants and antiperspirants cause breast cancer.
Myth: Wearing a bra increases your cancer risk. Fact: There is no good scientific or clinical basis to support the claim that plain or underwire bras cause breast cancer. This rumor appears to have started after a book called Dressed to Kill suggested that bras obstruct toxin-laden lymph fluid from flowing out of the breast. However, this was speculation based on a survey and no scientific evidence. Since then, major medical institutions, such as the National Cancer Institute and the ACS, have refuted the claim. If nonbra wearers do get breast cancer less often, it's probably because they tend to be thinner; obesity is a known risk factor.
Myth: Drinking from a plastic water bottle left in a hot car can cause cancer. Fact: This rumor falsely claims that dioxins—a group of toxic chemicals associated with an array of health problems, including breast cancer—leach from the heated plastic into the water.
Plastics do not contain dioxins, and the sun's rays are not strong enough to create them, says Michael Trush, PhD, deputy director of the Johns Hopkins Center for Urban Environmental Health.
Most single-use beverage bottles sold in the United States are made from polyethylene terephthalate (PET), a substance tested extensively for safety. There is some evidence that heat can cause bisphenol A (BPA), a compound that's been shown to have estrogenic effects in animal studies, to leach from plastic bottles into the water. (The "estrogenic effects" are thought to impact cancer risk.) However, most single-use water bottles sold in the United States are made from BPA-free plastic. And there's no proven link to breast cancer in women anyway. To be safe, drink from a reusable plastic bottle labeled "BPA free," or choose water bottles with a "1," "2," "4," or "5" in the recycling symbol on the bottom.
Myth: I had a normal mammogram, so I don't need to worry about breast cancer. Fact: Mammograms offer our best means of early detection—current guidelines still recommend them annually for women 40 and older—but they're not perfect. Research shows they can miss up to 20% of breast cancers in women who don't have any symptoms. Mammography reduces a woman's risk of dying from breast cancer by only 16%, according to the Dr. Susan Love Research Foundation. And just because one exam comes back normal doesn't mean breast cancer won't develop later—which is why current guidelines call for mammograms annually. To be safe, do self breast exams, paying particular attention to any changes in how your breasts look or feel. Women under 40 should have a clinical exam done every 3 years. Women 40 and older should get one yearly, along with a mammogram. Ask your doctor about the latest screening technology: Digital mammograms detected 15% more cancers in women under age 50 and 11% more in women with dense breasts, according to one study, and digital MRIs picked up 77% of cancers in women with a genetic mutation, compared with 36% detected by mammography. An MRI should be used in conjunction with, not instead of, a mammogram, according to the ACS.
Myth: Breast cancer is preventable. Fact: Although you can certainly address certain risk factors like obesity and inactivity, there's not enough information about what causes breast cancer for women to prevent it completely.
"There is a difference between things that are associated with a higher risk of breast cancer, such as obesity after menopause and alcohol, and what actually causes cancer," says Love. "It is likely that these are not the cause but either promote it or are in some way linked with it." A drug called Tamoxifen may reduce the risk of breast cancer in certain high-risk women—although more research is needed for treatments that apply to the general population—and double mastectomies can reduce the risk of breast cancer by more than 90% in women with a very high risk. To prevent breast cancer once and for all, more research is needed—especially studies that examine differences between women who get it and those who don't. By joining the Army of Women, you can help make this research happen.