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October 28, 2008
Antiperspirant and Breast Cancer
Breast cancer is the most common cancer among women. As life spans have increased in the United States, the prevalence of breast cancer has risen. Many women are concerned with the possibility of getting breast cancer at some point in their lives. This concern is amplified by the fact that there is no exact one cause for breast cancer, only a genetic component and a correlation with a wide variety of environmental factors and health behaviors.
In the midst of this fear of the disease, many claims about possible causes of breast cancer are made. Some are carefully researched and proved valid, while others are simply a product of speculation and rumors. Antiperspirant has been accused of being a cause of breast cancer. For the millions of women that apply antiperspirant daily, this sort of claim could increase anxiety and become an incentive to change personal hygiene habits if proven valid.
So let's take a deeper look for all those women (and men) who use antiperspirant daily, after showering, before a workout, or on a particularly hot day: should we sweat it?
BREAST CANCER BACKGROUND
About the Disease
Breast cancer is cancer found in the ducts or lobes of the breast, referred to as ductal or lobular carcinomas, respectively. These tumors are most common in the ducts, the tissue that is responsible for carrying breast milk to the nipple. Lumps can form every month, as a developed woman's breasts experience slight changes as a result of menstruation. Many of these lumps are nothing to worry about, but occasionally the lump can become cancer.
Tumors in the breast start out small and localized. Many are benign, and do not spread to other tissue. Others, called malignant or cancerous, invade other tissues in the body. The larger the tumor, the most likely the cancer is to spread, as cancerous cells are swept into the bloodstream or lymphatic system.
Figure 1. The Female Breast
Cancerous cells are different from normal cells. Cancerous cells divide uncontrollably and do not follow the normal cell life cycle. This uncontrollable division leads to the formation of tumors in the body tissue. Cancer becomes a more serious problem if the tumor metastasizes, or spreads, to tissue in other parts of the body.
Figure 2. Breast Cancer Cell
There is no exact known cause of breast cancer, but many risk factors have been identified. It is important to remember that having many risk factors does not guarantee you will get breast cancer, while many women with no risk factors will get the disease. Research suggests there is a genetic component. Risk increases as number of family members with the disease increases, especially if they are immediate family members. BRCA1 and BRCA2 have been indentified as breast cancer genes, and are present in approximately 10% of all cases. The other major factor is age. Research now links the sex hormones progesterone and estrogen to breast cancer; hormones dependent on pregnancy and menstrual cycle. Increased rates of cancer are found in women whose menstrual cycles began earlier or ended later than usual, as well as women who have their first child after the age of 30. (http://www.webmd.com/breast-cancer/guide/what-causes-breast-cancer) Beyond that, a variety of health behaviors and environmental factors have been linked to breast cancer, including diet and exposure to carcinogens.
Who it Affects
Figure 3. Women Walking for Breast Cancer Research
In the year 2008, it is predicted that over 180,000 women will be diagnosed with breast cancer (http://www.cancer.gov/cancertopics/types/breast). This disease can be found both men and women, although it is most common in women over the age of 50. Regardless, breast cancer affects everyone. Almost everyone is, at some point, a friend, coworker, or family member of someone with breast cancer. There are many support groups for patients and their loved ones, and tons of literature available online for those suffering. The widespread effects of this disease motivate us to continue research in hopes of better treatments, prevention methods, or a cure.
ANTIPERSPIRANT: THE SUSPECT
In recent years, a rumor began that antiperspirant is a leading cause of breast cancer. This rumor, much like a cancer, spread far and wide, thanks to the internet and a growing interest in natural and organic body products. Women became concerned; worried that what they considered a daily hygiene habit had the ability to cause breast cancer.
Around 1999, a chain e-mail circulated around the internet, forwarded from person to person. This e-mail named antiperspirants as the primary cause of breast cancer. The e-mail's author claimed that the proximity of the underarm (the common location of antiperspirant application) to the breasts was one piece of evidence. The author also claimed that by preventing sweating in the area, harmful toxins built up, and were then deposited in the lymph nodes near the breast, leading to mutations and then cancerous cells.
*****CLICK HERE TO READ THE SPAM EMAIL*****
Of course, e-mail chains are in no way a valid source of information. The motivation of the e-mail's author is unknown. He or she might have been a legitimately concerned individual, or someone who wished to spread a computer virus through a attention-catching e-mail. This e-mail alone offers no real scientific evidence or cites any sort of research. What it does do, however, is spread the rumor and get people thinking. Breast cancer is a scary subject, and fear is one of the greatest manipulators of the human mind. So when a household object as common as antiperspirant is suddenly claimed to be the cause of a major cancer, people take notice.
As the rumor was perpetuated, it began to become a subject of discussion on many internet websites and chats. Alternative health sites and women's health sites began to label antiperspirants and dangerous. As the rumor spread, the reasoning became more advanced and more plausible.
Antiperspirant works by blocking sweat glands and neutralizing odors. The active ingredient in antiperspirants is an aluminum-based compound. Common compounds include aluminum chloride, aluminum zirconium trichlorohydrex glycine, aluminum chlorohydrate, and aluminum hydroxybromide. The aluminum cations (Al3+) are taken into the top layer of the skin, taking water in with them in an osmotic process. As water (sweat) is absorbed back into the skin, the cells swell and the sweat ducts are effectively closed to a certain degree. (http://health.howstuffworks.com/question627.htm).
Figure 4. Skin Layers with Sweat Glands
The general claim is that aluminum compounds are absorbed into the skin, where they can act as toxins and build up. These sources link aluminum compounds to toxicity in the body, and therefore claim that the aluminum build up will cause breast cancer in that nearby area. Underarm shaving may cause nicks and cuts through which the aluminum compounds can enter the body. The fact that the upper outer breast is a common location for tumor growth is used as evidence by these sources. These health websites also name parabens, chemical compounds that may mimic estrogen in the body, as cancer-causing ingredients. (http://www.bellaonline.com/articles/art5651.asp) These websites tend to protect themselves by stating that there are no conclusive research studies that link antiperspirant use to breast cancer, but that it is always better to be safe than sorry.
The "better safe than sorry" attitude is understandable, but is it justified in this case? The hyperlink in the paragraph above leads to a prime example of this sort of website. It links to a short article written by the alternative health writer of a website targeted toward middle-aged women. It should be noted that this website also has pages that provide astrology profiles, internet games, and movie reviews. The credibility of this website as a source of accurate health information is questionable. Stereotypically, alternative health advocates tend to idealize the use of organic and natural products over chemically based products, regardless of effectiveness and actual harm to health. The main point to take away is that no conclusive evidence is presented here, only suggestions as to why antiperspirants might be cancer-causing products.
SHOULD YOU SWEAT IT?
Figure 5. Girl using Antiperspirant
What exactly are we trying to decide?
So is there need for concern? All of these rumors got people talking, and more explanations for why antiperspirants might be carcinogenic appeared. So let's review the claims we want to investigate:
● Antiperspirants cause breast cancer
● Aluminum from antiperspirants seep into skin through cuts in the skin caused by shaving
● Antiperspirants contain aluminum compounds and parabens
● Parabens cause cancer
● Aluminum compounds cause cancer
Let's take a look at the current research!
Internet Says: NO
The NIH's National Cancer Institute has complied a fact sheet online that deals specifically with the claim that antiperspirants cause breast cancer (http://www.cancer.gov/cancertopics/factsheet/Risk/AP-Deo#r5). This fact sheet uses researchers at the National Cancer Institute and NIH as experts to report on this claim. Step-by-step, the NCI examines the accusations made against antiperspirant and reports their findings based on current research, using a easy to read question and answer format.
The first point simply states that the NIH/NCI is unaware of any conclusive evidence that points to antiperspirant as a cause of breast cancer. They reference the U.S. Food and Drug Administration to state that the active ingredients in antiperspirants are not known to cause cancer.
The second point reports on the ingredients found in antiperspirants. Aluminum based compounds are used to form a "temporary plug within the sweat duct that stops the flow of sweat to the skin's surface". The site looks at a study that has suggested a link between aluminum compounds and estrogen-like effects, the problem being an increased level of sex hormones is considered a risk factor for cancers. Parabens have also been shown to act like estrogen in vivo, but most US products no longer contain these compounds. One study the NIC looked at claims that parabens can build up in the breast tissue, but this experiment did not study levels of parabens in other tissues as a comparison. This site also listed 4 studies, three of which found no link between antiperspirant use and breast cancer, and one that suggested there may be a relationship between underarm shaving and antiperspirant use and earlier diagnosis of breast cancer.
The NIH and NCI were established to improve the health of the nation through research and developing programs. Their focus on health shows their motive to be providing the public with accurate information about current health matters. This website also provides links to additional websites that may be useful to those dealing with a breast cancer diagnosis.
Another website called AntiperspirantsInfo has a page dedicated to the myths and facts about the link between antiperspirants and breast cancer (http://www.antiperspirantsinfo.com/english/index.php). It includes pages that list the ingredients in antiperspirants as: perfume, skin conditioner, oils/triglycerides, and aluminum salts. This site explains the function of each ingredient and claims aluminum salts are safe for use according to the US Food and Drug Administration.
The "myths & facts" page references the chain e-mail that first started the rumor regarding the link between antiperspirant and breast cancer. To address the e-mail's claim that blocking sweat glands leads to toxin build up, the site responds by saying the liver and kidneys perform this function. To refute the claim that the aluminum salts present in antiperspirant products cause the development of breast cancer, AntiperspirantsInfo references a study published by the Journal of the National Cancer Institute that finds no correlation.
Although this website contains useful information in an easy to navigate format, we must realize that there may be ulterior motives at hand. AntiperspirantsInfo is published by Unilever, one of the largest antiperspirant manufacturing companies in the world. This funding has an economic incentive to refute the link between antiperspirants and breast cancer. The site is helped by its references to the FDA and legitimate scientific journal articles, but it's important to keep in mind that information could also be withheld for Unilever's purposes!
Let's take a look at the current research literature and scientific journal articles ourselves and see what this information looks like without any sort of bias…
Research Literature Says: NOT NOW
1. One primary research report was entitled "An earlier age of breast cancer diagnosis related to more frequent use of antiperspirants/deodorants and underarm shaving" (McGrath, 2003). This report looked to see if a lifetime habit of using underarm antiperspirant and shaving was correlated with an earlier diagnosis of breast cancer. The author hypothesized that an earlier age at the time of breast cancer diagnosis would be correlated with a higher intensity and/or a earlier start of underarm shaving and antiperspirant use.
McGrath used a sample population of 437 female breast cancer
survivors to investigate his claim. His experimental design was a retrospective study where the female subjects were asked to remember and describe their past underarm shaving and antiperspirant application behaviors. The subjects were then divided into groups by intensity/starting age of usage. McGrath controlled for variables like family history, number of childbirths, age of first menstrual cycle, diet, estrogen use, exercise, and alcohol consumption.
His results show a significant correlation between age of breast cancer diagnosis and usage of antiperspirants and underarm shaving. His discussion focuses on past research that shows aluminum to have an adverse effect on biological processes. He states that hygiene habits play a direct role in depositing aluminum near the breast tissue, to support his findings. Aluminum is known to be capable of DNA alterations and epigenetic effects. Although his findings may be statistically significant, it is important to examine the validity of his methods. A retrospective study is a flawed method of determining causation. At best, significant findings with these studies suggest a need for further study of the impact of intensity of use and application of antiperspirants. Past long-term habits like underarm hygiene are especially difficult to recall accurately for a study of this nature. Subject selection involved self-response, meaning only those people who returned the questionnaire were included in the study, which may skew the data. Additionally, no non-breast cancer patients were included in the study as a control group to compare against.
2. A second study focused on the estrogen-like effects of parabens (Guadarrama, 2008). This study simulated these parabens in a simplified system that included a complex formed between estrogen receptors Arg, Glu, and His amino acids and 17beta-estradiol. Essentially, this study shows that methylparaben, the most paraben found most commonly in extracted tumors, was the most active paraben in this simplified model. The conclusion that may be drawn from this study is that methylparaben is found in tumors because of its likeness in function to estrogen, which is suggested to cause cancers in large amounts.
Assuming the simplified models are a reasonable approximation of the estrogen-binding system in the human body, it is safe to say that methylparaben exhibits some estrogen-like behaviors. Drawing from the studies that show a link between sex hormones and the development of breast cancer, parabens may prove to be a concern. This study does not, however, investigate how parabens may enter the skin of the underarm as an ingredient in an antiperspirant product. Fortunately, most antiperspirants sold in the United States do not contain parabens. It would be wise to check antiperspirant products for parabens under listed ingredients before use.
3. A third study published in the Journal of Inorganic Biochemistry, focused on aluminum as an active antiperspirant reagent (Darbre, 2005). This study was conducted because its author felt that sufficient information about the genotoxicity of aluminum was known, as well as the possibility of aluminum interacting with oestrogen (an established breast cancer risk factor) to affect its function in terms of ligand binding and gene expression, which would label aluminum as a metalloestrogen. This study was divided into 3 basic laboratory experiments that looked at: aluminum interference with oestrogen binding to the endoplasmic reticulum in cells, effects of aluminum growth of MCF7 human breast cancer cells, and effects of aluminum on oestrogen-regulated gene expression. Darbre's study references other studies that show aluminum's ability to be taken up through human skin. His aim is to see the short term effects of aluminum compounds in cells.
His first experiment shows that aluminum chloride can interfere
with binding to the endoplasmic reticulum in the cytoplasm of cells. He states that the mechanism for this potential interaction is as yet unknown, and the mechanism may not involve the ligand binding that would be expressed by oestrogen.
His second experiment shows that MCF7 cells (a line of breast cancer cells) proved to be resilient to aluminum compounds over a period of 2 weeks. This experiment suggests aluminum is not a cause of breast cancer; but also is not conducted for a long enough period of time to properly mimic the long term use of antiperspirant.
The third experiment shows that aluminum is able to increase oestrogen-regulated gene expression, as is oestrogen (the breast cancer risk factor). Darbre suggests that this display of metalloestrogenic properties requires further research.
In conclusion, this study focuses on the short term behaviors of aluminum in the body's cells, specifically as it relates to breast cancer cells and oestrogen's functions. Darbre's study suggests the need for long-term studies of aluminum's effects in the body, because of potential connections with the function of estrogen.
4. A fourth article (Namer, 2008) gives us a review of 59 separate reports that hypothesize a link between antiperspirant/deodorant use and breast cancer development. The 59 reports were found in the PubMed database. All of the 59 reports were reviewed by the team of researchers, and 19 of these were selected for in-depth analysis. Studies focusing on parabens were disregarded, as parabens are very rarely present in deodorants or antiperspirants. The remainder of these studies are considered methodologically unsound or irrelevant to the question at hand. Overall, the review paper found no evidence supporting a link between breast cancer and antiperspirant use. This review paper could be considered slightly objective, but the large number of studies of diverse methodologies gives it clout.
5. The last article we look at was published in the Journal of the National Cancer Institute (Mirick, D). This population based case-control study compared 813 case patients with 793 age-matched control subjects. An in person interview was the method used to collect information about antiperspirant use and frequency of use. Two-sided statistical tests were performed to evaluate any correlation between the behavior and the development of breast cancer. The study was limited to western Washington State. It included women aged 20-74 years. The in person interview dealt with a large number of suggested risk factors, antiperspirant uses being some of them. The study explored regular antiperspirant use, exclusive antiperspirant use (vs. deodorant), and application time relative to underarm shaving time. Odds ratios were calculated to determine whether antiperspirants were a risk factor.
This study found no significant link between underarm antiperspirant application and breast cancer. This study, rather than being of a chemical or biological nature, was epidemiological. It is important to remember than when dealing with people, there is always the possibility of misreporting or human misjudgment. There is also the chance that this study is too broad to catch any subtle or detailed link between the antiperspirant's ingredients and an increase in breast cancer risk. This study does, however, provide us with an overall view of the severity, or lack there of, of using antiperspirant and developing breast cancer as a result.
So what's the deal?
Many people have suggested antiperspirant use as a potential risk factor for developing breast cancer. Currently, there is no proven link between breast cancer and antiperspirant use. The ingredients in antiperspirants have been proven to have the ability to affect biological function and possibly mimic the effects of risk factor estrogen. However, there are no studies that discuss a direct link of these active ingredients to breast cancer. The epidemiological studies do not show antiperspirant use as a risk factor among the general population. These large-scale studies are the best, most relevant studies we have on the matter today.
What should researchers do now?
The general consensus seems to be that there is no current link between antiperspirant use and breast cancer development. There is research that suggests aluminum and parabens, two active ingredients that are potentially present in antiperspirants, have biological effects in high concentrations. Luckily, parabens are no longer found in antiperspirant products sold in the United States, so it becomes a non issue. The next logical step for researchers would be to examine the effects of the aluminum compounds in the long-term. Another potential area of research is the mechanisms by which these compounds interact in the human body. Answering both of these questions would help advance breast cancer research, as well as various other areas of biological research.
What should I do now???
Your health is your own personal choice, and it is important to form your own opinions and make your own decisions. Hopefully the opinions expressed by these articles will help you to decide whether you think antiperspirant use is for you. It is impossible for us to know what discoveries could be made in the future regarding this matter, but for now, you can feel ok about including antiperspirant in your hygiene routine. Antiperspirants are not definitively proven as breast-cancer causing agents, so there is no official reason to fear. In other words, don't sweat it! If you are concerned about breast cancer, maybe because of your environmental circumstances or a family history, the most important thing you can do is focus on maintaining a healthy lifestyle. I hope you decide to take a proactive stance on your personal health!
And Where You Can Go to Learn Some More!
Darbe, P.D. (2005). Aluminum, antiperspirants, and breast cancer. Journal of
Inorganic Chemistry, 99(9). Retrieved October 8, 2008, from PUBMED database.
Guadarrama, P., Formine, S. Salcedo, R., Martinez, A. (2008). Contruction of
simplified models to to simulate estrogenic disruptions by esters of 4-hydroxy benzoic acid (parabens). Biophysical Chemistry, 137(1). Retrieved October 8, 2008, from PUBMED database.
McGrath, K.G. (2003). An earlier age of breast cancer diagnosis related to more
frequent use of antiperspirants/deodorants and underarm shaving. European Journal of Cancer Prevention, 12(6). Retrieved October 8, 2008, from PUBMED database.
Mirick, D.K., Davis, S., Thomas, D.B. (2002). Antiperspirant Use and the Risk of
Breast Cancer. Journal of the National Cancer Institute, 94. Retrieved October 8, 2008 from PUBMED database.
Namer, M., Luporsi, E., Gligorov J., Lokiec, F., Spielmann, M. (2008 Oct 1). The
use of deodorants/antiperspirants does not constitute a risk for breast cancer. Bull Cancer, 95(9). Retrieved October 8, 2008, from PUBMED database.
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