Briefly in regard to study participation:
pros: they pay--not you/you MAY get the very latest therapy, the best there is at the time
con:that's the nature of a study-they have to compare the investigational drug against something, either another drug, or perhaps no drug. For it to be a well-designed trial, neither the patient or the doctor should know who's getting (or not getting ) what. Everyone in a clinical trial is a volunteer. No one is pressured to participate. Nobody wants the placebo, but someone has to for it to be a valid trial. Also, some trials compare two drugs, or two dosages. Or some other variable. Not all involve placebos.
A surgeon will often say they "got it all", but that means they got it all they can find. If there's a met hiding somewhere else, it's going to be a problem later. Suggestion: definitely go to an experienced kidney cancer oncologist. Surveillance CTs necessary to check for recurrence. We are in this for the long haul.
Good luck.
Bob