A couple of weeks ago, a Facebook friend posted a link to a web article claiming a recent study showed use of deodorant was linked to breast cancer. The website touted ‘natural’ products and ‘holistic’ approaches to health and wellness. Guessing their conflict of interest in peddling ‘natural’ and ‘holistic’ deoderants might have skewed their take on the research, I looked up the original journal article. “Measurement of paraben concentrations in human breast tissue at serial locations across the breast from axilla to sternum” by L. Barr et al. in the Journal of Applied Toxicology.
I read the paper and realized the holistic website did WAY overstate the conclusions, told my friend it was bogus, and went on my merry way.
Then today, what headline do I see on Yahoo News? “Study proves my 80-year-old grandfather correct: Deodorant may promote breast cancer” by Summer Banks, a Yahoo Contributor. According to her bio, Summer has 4 years of college nursing eduction, but isn’t a nurse, she’s a medical assistant. While I’m sure that makes her more knowledgable than your average woman on the street when it comes to medical expertise, it apparently does not make her capable of reading and comprehending primary research papers. Alternatively, she may be spinning the results for a shocking headline that Yahoo will pay her for or to promote the brand name products she mentions in the ‘news article.’
So thanks to Yahoo and Summer, I now feel it necessary to address this paper and share what researchers actually did, what they actually found, what they actually concluded, and what it actually tells us about deodorant and breast cancer.
In a nutshell:
What the researchers actually did was collect human breast tissue from 40 mastectomies performed on patients with breast cancer. They tested these samples for the presence, amount, and type of parabens (a component of deodorants, but also found in other stuff too, click the link for more info).
What the researchers actually found was that 99% of the samples had detectable levels of at least one paraben and 60% had detectable levels of all five of the parabens they tested for.
What they actually concluded was that, “The results of the current study confirm and expand our previous work (Darbre et al., 2004) and indicate that intact paraben esters can be measured in human breast tissue.” (Not exactly the headline Summer was going for.) “The current study has provided a larger sample size (160 rather than 20), and multiple sampling at four serial locations across the breast (axilla, lateral, mid, me- dial) has enabled study of the distribution of parabens across a single breast for the first time.”
Now, for what the researchers did NOT do/find/conclude…
The researchers did NOT compare breast tissue from patients with breast cancer to those without. Thus, for all we know, the levels of parabens might be equally high in both cases, meaning that the presence of parabens isn’t the whole story, or that parabens aren’t correlated with breast cancer. This failure to compare tissue from patients with and without cancer is a major stumbling block for this research paper. I was actually surprised the authors were able to get it published without that comparison. I’m guessing that the reason they were only able to conclude that parabens were detectable- and not make a single conclusion about breast cancer and parabens- is because they lacked this crucial comparison.
The researchers did NOT find a correlation between the paraben levels and the presence of cancer in a region of breast tissue. Meaning paraben levels were similar in regions in which tumors were found and in cancer-free regions.
The researchers did NOT find a correlation between use of deodorant and levels of parabens, meaning there is no link between parabens in breast tissue and use of deodorant (I guess Summer must have missed that because her headline says the exact opposite of this).
The researchers did NOT conclude that there was a causal link between parabens and breast cancer. They did NOT conclude that the parabens present in breast tissue came from deodorant. They did NOT conclude that the levels of parabens found were sufficient to stimulate tumor growth.
OK. Now that we have that out of the way- let’s break it down and see how well Summer’s reading comprehension is.
Summer Banks wrote (as the headline!): “Deodorant may promote breast cancer.”
The researchers wrote: “The finding of similar concentrations of parabens in the breast tissue of women who reported to be current, past or nonusers of underarm cosmetics suggests the parabens to have originated from a source other than underarm cosmetic application.”
So, it’s not the deodorant! Summer is wrong.
The researchers also wrote: “The presence of a chemical in the breast cannot be taken to imply causality per se…”
So they didn’t prove any causes! Summer is wrong. (Although half-credit since she did say “may cause breast cancer”)
Summer Banks wrote: “The study went on to reveal that paraben levels were high enough to cause estrogen-based cancers, like breast cancer, to grow faster.”
The researchers wrote: “Although oestrogen is an acknowledged component in the development of breast cancer (Miller, 1996), it remains to be established as to whether environmental chemicals with oestrogenic properties [like parabens] contribute a functional component to the disease process (Darbre and Charles, 2010).”
So, the parabens aren’t causing cancer to grow faster! Summer is totally wrong here. The study performed no such experiments and drew no such conclusions. Actually the study didn’t even show a single piece of data about the growth of cancers AT ALL.
Summer Banks also wrote: “There are no medical studies, including this study, that prove parabens cause breast cancer…”
Why then the headline that deodorant may cause breast cancer?
Perhaps it has to do with the products Summer mentions as safe alternatives to traditional deodorant? Hawking products is always a red flag that a source isn’t reliable and may have a conflict of interest that means it cannot be trusted. See here for how to spot a reputable information source.
I really cannot believe how inaccurate Summer Banks’ article is. I hope she sees this post and either corrects the article’s blatant inaccuracies or withdraws the article entirely. The last thing we need is misinformation being passed off as news.