Debbie, PJ is right. Your situation is not typical, and you may need to go beyond usual cancer treatments. The treatments for kidney and breast cancer are not necessarily the same, so you need specialists who can figure out how to balance the treatments for your different conditions. I have read about some people whose cancer metastasizes to an unusual place, so it is possible, though not likely, that you have kidney cancer cells in your breast, or breast cancer cells in your kidney. Again if that is the case, a comprehensive cancer center or research hospital is the best place to deal with this unusual situation.
Debbie, so far as I know, kidney cancer can't spread to the breast. And breast cancer can't spread to the kidneys. So if it's true you have both, they've developed independently of one another. Sounds like you might have a complicated diagnosis going on here; I'd suggest, if at all possible, you ask for a second opinion at a Comprehensive Cancer Center, which are cancer centers around the country the government has designated "best in class." They see a LOT of cancer patients, and thus have great experience dealing with all kinds of situations. I wish you all the best as you go through this- PJH