Welcome to our little corner of the internet! Glad you found us and hopefully you will stick with us for a while...We are at all stages with the disease, from those who are newly diagnosed to our "old timer" 20 year survivor!
I had always heard that soy is a phytoestrogen (plant based estrogen) and that since they tell us to stay away from hormones, we should stay away from phytoestrogens too. I do not go out of my way to avoid it in small quantities, but I do not use the milk or other soy based dairy products. I would ask the oncologist about it, and perhaps consult a nutritionist at the cancer center for recommendations. I would think that any amount of soy you had was pretty small and insignificant, but please ask the doc or RN.
Also, be careful what you read on the internet. There are a lot of folks selling snake oils and such. Try to stick to websites that have .org, .gov or .edu to remain with reputable ones.