Hi there,
I don't have any experience with your condition, but did have carboplatin and paclitaxil for endometrial cancer. I am about to go on hormonal therapy. I too am concerned that it will do any good, and neither does my oncologist. At this point it is the best of all "evils" as far as side FX. If it proves to be useless, or my condition worsens, I'd be put on targeted therapy, which my onc. referred to as "the big guns".
In any event, I strongly suggest you talk to your oncologist about your concerns and learn as much as you can about the treatment s/he is suggesting. In addition, have him/her refer you a kidney specialist to discuss the matter.