Can pretty smelling pits cause cancer?

There has been a rumor out there since I was in elementary school that antiperspirants and deodorants caused breast cancer, and many people that I know still live and die by that statement.  I have always thrown caution to the wind with this one, as an athlete and as someone who sweats a lot, to keep my friends and people close to me happy and smelling nothing but goodness!

First of all, there is a difference between deodorant and antiperspirant: deodorant merely covers the scent of sweat, whereas antiperspirant prevents the amount of underarm sweat.  Both preparations are absorbed through the pores in the skin, and specifically in women, the theory is that these preparations can be absorbed in larger amounts through possible cuts in the skin from shaving, also that certain ingredients (mainly aluminum gets the most press) can be absorbed so close to breast tissue which is said to increase the risk of breast cancer.  But is it?  The aluminum based products clog the sweat pore up, not allowing sweat to come out, and possibly be absorbed and have estrogen-like effects (some breast cancers are hormone sensitive and grow bigger with higher levels of estrogen).  (from the Journal of the National Cancer Institute 2000, Journal of Applied Toxicology 2003, and Journal of Inorganic Biochemistry 2005).

So what are the results??
In shocking news: the results are mixed!!!  In a 2002 study by the National Cancer Institute, which was a study performed on around 1600 women in the US, and found no correlation between use of antiperspirant and deodorant or shaving using a regular razor or electric.

In 2003,  a study from the European Journal of Cancer, looking at 437 breast cancer survivors found that the age of breast cancer diagnosis was much earlier in women who used antiperspirants/deodorants and shaved frequently, and in those that started using these products under the age of 16.

A study in 2006 in the Eastern Mediterranean Health Journal found that in around 100 subjects there was no association with breast cancer and antiperspirant/deodorant use but it was related to family history (which is undoubtedly true) and oral contraceptives (needs further investigation but there is a very weak link).

What does Nurse Bridgid say?
These studies are all pretty weak, they are based on interviews with subjects after the fact, and the first two studies don't really take other exposures and family history into account.  If this is something that you are really worried about, you can try all natural deodorants or powders that don't contain aluminum.  If you have a strong family history for breast cancer, then you should take every precaution and talk to your HCP about ways to prevent breast cancer and get BRCA1-2 testing done (genetic testing for risk of breast cancer).  Otherwise, I say deodorant and antiperspirant it up!!  No need it make others smell your pits if they don't need to!!  So keep up the good hygiene!!

Yours in Good Health
B