October is breast cancer awareness month, and a perfect time to set the record straight about some commonly held misconceptions regarding this disease. Impacting about 12 percent of women at some point during their lifetimes, breast cancer is the most common cancer among U.S. women (except for skin cancer).
The American Cancer Society estimated that nearly 230,500 new cases of invasive breast cancer would be diagnosed in women in 2011, and another 57,650 would be diagnosed with carcinoma in situ (CIS), which is the earliest, non-invasive form of breast cancer.1 While breast cancer is the second leading cause of cancer deaths among women (second to lung cancer), there are over 2.5 million breast cancer survivors in the United States, and when detected early, the five-year survival rate is 96 percent.2
So breast cancer is often very much a disease that can be overcome, and in many cases prevented entirely. Getting the facts straight about the real risk factors of this disease is one of the best ways to be proactive about prevention. We urge you to not only get informed about these misconceptions yourself, but also share them with your friends and family as well.
Breast Cancer Risks: What’s Real and What’s Not?
The notion that deodorant and antiperspirant can cause breast cancer has been widely circulated on the Internet and specifically states that when you shave, tiny cuts in your underarms allow cancer-causing chemicals to be absorbed. There are, however, no epidemiologic studies showing this association to be true.
According to the American Cancer Society, one 2002 study of 813 women found no link between antiperspirant use and breast cancer. And as for a 2003 study that found women diagnosed with breast cancer at a younger age reported shaving their underarms earlier and more often than women diagnosed when they were older, the study design did not include a control group of women without breast cancer and could not identify a causative effect.3
However, it’s important to be aware that there are certain chemicals commonly used in deodorants and antiperspirants that have, in fact, been linked to cancer. This includes parabens, which can mimic the hormone estrogen, an increase of which has been linked to an increased risk of breast cancer. One study found parabens in every sample of tissue taken from 20 breast tumors.4
Another substance of concern in antiperspirants is aluminum, which has also been found to have estrogen-like effects that may play a role in cancer.5There is evidence that aluminum from antiperspirant is absorbed and present in breast tissue. Researchers have concluded:6
“We have confirmed the presence of aluminum in breast tissue and its possible regional distribution within the breast. Higher content of alumiium in the outer breast might be explained by this region’s closer proximity to the underarm where the highest density of application of antiperspirant could be assumed. There is evidence that skin is permeable to aluminum when applied as antiperspirant.”
Avoiding environmental chemicals as much as possible is a smart choice to minimize your risk of all types of cancer, so choosing a chemical-free, natural deodorant is a sensible option.
2. Breast Size
Breast size is not a strong indicator of breast cancer risk, although there is some research indicating that lean women with larger breasts may have a higher risk.
One study found premenopausal women with a BMI under 25 and a bra cup size of “D or larger” had a significantly higher incidence of breast cancer than women who reported “A or smaller.”7 Separate research also revealed a link among postmenopausal women, with those reporting a chest size under 34 inches and a cup size B or C at a higher risk compared to a cup size smaller than B.8 These associations appear to be limited to those who were especially lean as young women.
That said, obesity is a risk factor for breast cancer, and obese women tend to have larger breasts. If you’re overweight, losing even 5 to 10 percent of your total weight can be beneficial. Further, women with dense breast tissue, meaning you have more glandular tissue and less fatty tissue, have a higher risk of breast cancer as well. Dense breast tissue has nothing to do with breast size, and can be revealed with a mammogram.
If your mom, grandmother or sister had breast cancer, does it mean you will too? In a word, no. By making positive lifestyle choices, including healthy diet and exercise, you can help your genes express in a way that helps prevent diseases like cancer.
That said, if you do have a close relative (mom, sister, daughter) with breast cancer, it may be even more important for you to adhere to a healthy lifestyle, as this is estimated to double your risk. If you have two close relatives with breast cancer, your risk increases by about three-fold. Again, this is NOT a guarantee that you will get cancer, just an indication that you may have a higher risk, and should take preventive options, especially healthy lifestyle choices, seriously. You may also want to consult with your doctor regarding assessing the risk and benefits of more frequent mammograms.
It’s also thought that about 5-10 percent of breast cancer cases are the result of genetic defects inherited from a parent.9 Most often this involves a mutation in the BRCA1 and BRCA2 genes, which actually help prevent cells from growing abnormally and leading to cancer. When a mutation is present, this natural cancer prevention is missing and your risk of developing breast cancer increases, sometimes significantly. There are genetic tests available to identify mutations in the BRCA1 and BRCA2 genes, as well as other less common mutations, however the results, and the best steps to take next, are not always straightforward.
Mammograms are x-rays of the breasts intended to detect cancer in its early stages, before a lump can be felt. Because all x-rays expose you to radiation, there has been some concern that regular mammograms may actually increase your risk of radiation-induced cancer. This is a real risk, albeit most likely a relatively small one, so it’s up to you to weigh your options.
According to research in the journal Radiology, annual mammography screening of 100,000 women from age 40-55, and biennial screening after that to age 74, would result in 86 radiation-induced cancers, including 11 fatal cancers, and 136 life years lost. They estimated that in the same group, 497 lives and 10,670 life years would be saved by earlier detection.10
There is also some evidence that women with BRCA 1 and 2 mutations are particularly susceptible to radiation risks, and may increase their risk of breast cancer by more than 50 percent by having a chest x-ray such as a mammogram.11
One way to keep your radiation risks from mammography as low as possible is to wait on annual screening until age 50. Updated guidelines from the U.S. Preventive Services Task Force (USPSTF) recommend that women in their 40s should NOT get routine mammograms, which is a departure from other health agencies, which typically recommend screening begin at age 40.
Does wearing a bra increase your risk of cancer? This myth has been widely circulated online, stating that bras increase your risk of cancer by obstructing lymph flow, however no peer-reviewed scientific studies bear this out.
The rumor stems largely from the book “Dressed To Kill: The Link between Breast Cancer and Bras,” which cited preliminary research that women who wear tight-fitting bras 24 hours a day are 125 times more likely to have breast cancer than women who do not wear bras at all.
However, as Dr. Ted Gansler, director of medical content for the American Cancer Society, explained in the New York Times:12
“The study, never published in a peer-reviewed journal, did not adjust for known breast cancer risk factors that might be associated with bra-wearing behavior, like weight and age. Also, study participants knew the hypothesis before taking the survey.
He [Gansler] and colleagues compared National Cancer Institute data on breast cancer risk for women treated for melanoma who had several underarm lymph nodes removed and those who did not. The surgery, which is known to block lymph drainage from breast tissue, did not detectably increase breast cancer rates, the study found, meaning that it is extremely unlikely that wearing a bra, which affects lymph flow minimally if at all, would do so.”
6. Birth Control Pills
Oral contraceptives like the pill contain female hormones including estrogen, and the increased hormonal exposure has been linked to a slightly increased risk of breast cancer. The risk was found to be highest among women who began using birth control pills as teenagers (and therefore were exposed to the hormones the longest), and the increased risk appeared to taper off 10 or more years after usage stopped.13
Other research has been conflicting — the Women’s Contraceptive and Reproductive Experiences (Women’s CARE) study found no significant association between use of birth control pills and breast cancer14 while a National Cancer Institute study found women who had used birth control pills within five years were the most likely to be diagnosed with breast cancer, compared to those who had used them 5-10 or 10 or more years ago, or not at all.15
If you’re concerned about exposure to synthetic hormones in birth control pills, consider non-hormonal contraceptives instead.
What Can You Do to Prevent Breast Cancer?
For top tips on how to prevent breast cancer, be sure to see the blog posts below; it’s estimated that up to one-third of breast cancer cases are entirely avoidable with healthy lifestyle changes such as exercise, weight loss and healthy eating habits.
1. American Cancer Society, Breast Cancer
2. The Breast Cancer Site, About Breast Cancer
3. American Cancer Society, Antiperspirants and Breast Cancer Risk
4. Journal of Applied Toxicology. 2004 Jan-Feb;24(1):5-13.
5. Journal of Inorganic Biochemistry. 2005 Sep;99(9):1912-9.
6. Journal of Inorganic Biochemistry 101 (2007) 1344–1346
7. International Journal of Cancer. 2006 Apr 15;118(8):2031-4.
8. Cancer Causes and Control. 1999 Apr;10(2):115-8.
9. American Cancer Society, Breast Cancer Risk Factors
10. Radiology January 2011, 258, 98-105.
11. Journal of Clinical Oncology, Vol 24, No 21 (July 20), 2006: pp. 3361-3366
12. The New York Times, Bras and Cancer February 15, 2010
13. Lancet. 1996 Jun 22;347(9017):1713-27.
14. New England Journal of Medicine 2002; 346(26):2025–2032.
15. Cancer Causes and Control 2003; 14(2):151–160.