Hi David
This is Kathy from BCNA's Policy Team. Di has asked me to reply to your questions about deodorant and breast cancer risk.
As you have found, there is no conclusive evidence that using anti-perspirants or deodorants can increase a woman’s risk of developing breast cancer. The US National Institutes of Health, which is the US government's principal agency for cancer research and training, has a fact sheet available on its website which talks about this issue. That is the best information I can point you towards.
If you are interested in reading more about breast cancer risk factors, you might like to look at the Breastcancer.org website. This is a US-based website which we often refer to. It provides reliable, quality information. It also finds there is no scientific evidence that deodorants increase breast cancer risk.
David, like so many others who have responded to your blog, I would like to extend to you my sympathies on Nonie's passing.
Kathy