I had both cancers. I had my thyroid removed and 10 weeks later I had a severe pain in my back and my husband rushed me to the hospital. I had a tumor on my kidney bigger than a fist. Needless to say I had my kidney was removed. The doctors say they were unrelated. That my kidney cancer was growing longer. I only had papillary thyroid cancer not advanced.
I went to an oncologist and she said that they are unrelated but it makes you wonder.
Sorry I couldn't be of more help.