Five persistent myths about the causes of breast cancer
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.