Re: kidney removed due to cancer then it came back what know
My husband also had his left kidney removed some years back due to a grade 1 cancerous tumor. Thankfully it was grade 1 and so far all follow-up scans have been clear, and there is no sign of metastasis.
What grade was your BIL's tumor? meaning, was it caught early, or was it already in it's later stages? if it was caught in it's later stages (grades 3 or 4), then that's when there is more chance of it spreading.
Wishing your BIL the very best and hope any future treatment can help him.