My mother has lung cancer. we were told her kidneys are shrinking. does this mean kidney failure?

Kidney size: Smaller kidneys typically means scar is setting into the kidneys. The diagnosis of kidney insufficiency or kidney change in function requires blood testing of serum creatinine level, which is routine. Ask the doctor to measure serum creatinine value as soon as possible. It should be less than 1.2.

I would guess...: ...that too, but "shrinking kidneys" is not a term I would use. Some physicians try hard to explain a situation in lay terms (and with the best of intentions) but I personally think we can help patients understand while still being accurate in our explanations. Don't walk away from a doctor's visit with questions. If u don't understand what he/she said, ask for clarification. Best to you both.