Understanding what causes a type of cancer is vital to prevent more cases in the future. But it can feel like we’re being told to avoid a new thing every day because it might cause cancer. A survey in the US found that agreement with the phrase: “It seems like everything causes cancer” is on the increase – even though, thanks to research, we know more about what causes and prevents cancer than ever before.
As it’s Breast Cancer Awareness Month, we’ve examined some common myths around the causes of the disease. More than 1 in 4 cases of breast cancer could be prevented, meaning there are some definite avoidable causes out there (as well as some we sadly can’t avoid). But you might be surprised by what’s missing from the list.
Being sure about what causes cancer isn’t easy. It takes years of research based on huge numbers of people to get a clear picture of what increases or decreases our risk. Most of the evidence tied to these myths isn’t strong enough to suggest they actually cause cancer. And without a clear enough indication that these things could be a genuine issue, it’s not worth investing in more research when that time and money could be used for science that has a real impact.
Often, because of this lack of good evidence, it’s not possible to disprove any potential link entirely, but we can say the research available doesn’t hold up to scrutiny. Essentially, it’s very hard to prove a negative (which may be why the International Agency for Research on Cancer (IARC) has only ever classified one substance as probably not a cause of cancer in people).
But the good news is there’s no reason to be concerned about the deodorants, bras, plastics and milk we encounter every day.
1. Cosmetics and deodorants
Rumours about deodorants and other cosmetics causing breast cancer started as an email hoax. There’s no sound scientific evidence that deodorants cause breast cancer. There aren’t enough good quality studies to rule out a definite link, but the most recent review showed no link. If anything, it actually showed a possible protective effect, suggesting there may be other factors that accompany deodorant use that might be decreasing breast cancer risk, such as regular exercise.
Some of the myths around deodorants claim that aluminium, the active ingredient in most deodorants, causes breast cancer, but a review of the evidence has disputed this. It’s also worth pointing out that all cosmetics sold in the UK are tightly regulated and have to be shown to be safe.
2. Myths about bras aren’t supported
Wearing a bra or keeping a mobile phone in your bra hasn’t been shown to cause cancer. There hasn’t been much research into this because there’s no scientific way that suggests how bras and cancer might be linked. The only relevant study we found on the research database PubMed didn’t find a link between wearing a bra and breast cancer so women don’t need to worry about getting the support they need.
Although we can’t know for sure the potential long-term impact of using mobile phones on other types of cancer, scientists believe a link is unlikely. This has been most closely studied in relation to brain tumours. And it’s something researchers will keep an eye on.
3. What you’re drinking is more important than what the bottle is made of
Most of the concerns around plastic containers focus on whether the chemicals inside the plastic can move into food or drink. There’s some evidence that this might occur, but only in very low levels. And experiments testing plastics don’t necessarily reflect how people use these products so levels are likely to be far below what might be deemed unsafe. You can read more about this myth on our website.
And again, in the UK there are rules in place to make sure the materials used for food and drink packaging aren’t harmful to people.
4. Milk myths
We’ve been asked about milk (or dairy more broadly) a lot lately, including the impact of hormones on breast cancer risk. Lots of studies have looked at how the things we eat and drink might affect our risk of cancer. And the World Cancer Research Fund regularly updates where the consensus lies based on all this research. In a thorough review they found no link between consuming dairy products and breast cancer.
Some studies suggest a potential decreased risk of bowel cancer from consuming dairy products, but the evidence isn’t strong enough to make claims or give people specific advice.
5. Genetics doesn’t play as much of a role as you may think
For some people with a really strong family history of breast cancer the risk tied to inherited faulty genes is important. The most famous of these are the BRCA genes. But the total number of breast cancer cases caused by inherited faulty genes is smaller than you might believe based on the media attention they often receive. It’s actually fewer than 3 in 100 cases of breast cancer that are caused by inherited faulty genes.
So what does affect the risk of breast cancer?
It’s impossible to know for sure what caused each individual breast cancer. But the evidence from years of research has shown there are some things that can help you stack the odds of avoiding breast cancer in your favour. Keeping a healthy weight, drinking less alcohol and keeping active all make a difference, and that is backed by evidence.
There are also some other factors you can’t control, such as getting older. And others may be difficult to avoid. Taking HRT and being exposed to radiation (mostly from necessary medical procedures) also increase the risk of breast cancer – and it’s important women are aware of this when they’re making healthcare decisions. On the other hand, breastfeeding decreases risk, but not everyone is able to and there are other factors that can influence this decision for women.
Not all breast cancer myths focus on supposed causes of the disease. Women may have been told to check their breasts in a particular way, time or place. But they don’t need to. The important thing is getting to know what’s normal for you, and to tell your doctor if you notice any unusual or lasting changes.
As ever, good quality research – rather than hoaxes and anecdotes – is the best way to keep an eye on new potential causes of cancer.
And with clear information available on what people can do to reduce their risk, it’s best to ignore the scare stories.
Nikki Smith is a senior health information officer at Cancer Research UK
Christine Liddell October 30, 2017
your article makes good reading ,but I’m not sure about what you say about families with the BRACA faulty gene ,we have the braca 2 gene in my family ,my parents had 6 children ,5 girls and 1 boy ,of the 6 of us 5 have the faulty gene ,only 1 of my sisters doesn’t have it ,sadly she is suffering from M.S…. , with us the gene came down my fathers side,his mother and sister both suffered Breast Cancer and thankfully survived for a long time after ,I am 1 of 4 sisters who have all had breast cancer,and 1 sister as actually been through it twice, my Dad was diagnosed aged about 80,by which time they could do nothing for him, so we had to watch him suffer ,until he passed away just before his 82nd birthday, and I have to say that when it is said change your diet get more healthy ,will help you to not suffer this awful disease , if you have the faulty gene you are highly unlikely not to get a diagnosis…. this is why my eldest daughter and 3 of my nieces decided to have double mastectomy’s ,and reconstruction,my younger daughter will have the same op as soon as she has completed her family , thankfully I do have nieces that have not got the gene and we all thank God for that….
Nikki Smith October 16, 2017
Hi Cancer Treatment,
Thanks for your comment.
The signs and symptoms of breast cancer can be quite different for each woman, so it’s important to get to know what’s normal for you and see your doctor if you notice any unusual changes. You’re right that fluid leaking from a nipple could potentially be a sign of breast cancer in a woman who isn’t pregnant or breastfeeding. Also a change in the size, shape or feel of a breast, a new lump or thickening in a breast or armpit, skin changes such as puckering, dimpling, a rash or redness of the skin, changes in the position of a nipple or pain in a breast.
Changes are more likely to be something less serious than cancer but it’s best to get checked out.
Nikki, Cancer Research UK
Sydney Ross Singer October 14, 2017
I am a medical anthropologist breast cancer researcher and co-author of Dressed to Kill: The Link Between Breast Cancer and Bras. This article is biased and misleading about the bra-cancer link. There are numerous studies which show a link, which this article ignores. See below for some references. Also, the only reference the article gives is to a study that did not include any bra-free women as a control group. It only included women over 55 who were lifetime bra users. That’s like studying the smoking-cancer link and excluding nonsmokers for comparison. That study was designed to try discrediting the bra-cancer link, since this information is inconvenient for the embarrassed cancer industry.
The fact is that bra-free women have about the same risk of breast cancer as men, while the tighter and longer the bra is worn the higher the risk rises. Tight bras also cause breast pain and cysts, and are the leading cause of breast disease in bra-wearing cultures.
SOME STUDIES THAT SUPPORT THE BRA/CANCER LINK:
1991 Harvard study (CC Hsieh, D Trichopoulos (1991). Breast size, handedness and breast cancer risk. European Journal of Cancer and Clinical Oncology 27(2):131-135.). This study found that, “Premenopausal women who do not wear bras had half the risk of breast cancer compared with bra users…”
1991-93 U.S. Bra and Breast Cancer Study by Singer and Grismaijer, published in Dressed To Kill: The Link Between Breast Cancer and Bras (Second Edition, Square One Publishers, 2018). Found that bra-free women have about the same incidence of breast cancer as men. 24/7 bra wearing increases incidence over 100 times that of a bra-free woman.
Singer and Grismaijer did a follow-up study in Fiji, published in Get It Off! (ISCD Press, 2000). Found 24 case histories of breast cancer in a culture where half the women are bra-free. The women getting breast cancer were all wearing bras. Given women with the same genetics and diet and living in the same village, the ones getting breast disease were the ones wearing bras for work.
A 2009 Chinese study (Zhang AQ, Xia JH, Wang Q, Li WP, Xu J, Chen ZY, Yang JM (2009). [Risk factors of breast cancer in women in Guangdong and the countermeasures]. In Chinese. Nan Fang Yi Ke Da Xue Xue Bao. 2009 Jul;29(7):1451-3.) found that NOT sleeping in a bra was protective against breast cancer, lowering the risk 60%.
2011 a study was published, in Spanish, confirming that bras are causing breast disease and cancer. It found that underwired and push-up bras are the most harmful, but any bra that leaves red marks or indentations may cause disease.
2015 Comparative study of breast cancer risk factors at Kenyatta National Hospital and the Nairobi Hospital J. Afr. Cancer (2015) 7:41-46. This study found a significant bra-cancer link in pre-and post-menopausal women.
2016 Wearing a Tight Bra for Many Hours a Day is Associated with Increased Risk of Breast Cancer Adv Oncol Res Treat 1: 105. This is the first epidemiological study to look at bra tightness and time worn, and found a significant bra-cancer link.
There are more studies, but these show that there is scientific support for this issue. However, I don’t expect this article to correct this misinformation since there is a concerted effort to suppress it by the cancer industry, and this article seems part of that plan.
Cancer Treatment October 14, 2017
Hi Nikki. Interesting article. After the death of one of my relatives due to breast cancer. I am more aware now about this cancer. I’ve read an article about Breast Cancer. Clear or blood-stained discharge from the nipple is one of the typical symptoms of breast cancer. Is it true?