If the records are lost, I'm not sure what else they can really do.
However, I would suggest that you request a copy of your records that they do have AND that you request a copy of the Dr. notes for every subsequent appointment you have in additionl to a copy of every pathology, culture, scan, and whatever other test/procedure gets done from now on.
Keep all the records well organized, check them for accuracy, and consider creating a summary. I found the summary to be quite helpful when I went for second and third opinions. I started from my very first Uro visit and listed symptoms I had that got me referred to the Uro in the first place. I just listed the date, the procedure and the notable differences from norm. Stuff that was normal, I just said normal or negative or whatever made sense in the particular instance. Tests that had results that had some things normal and some things not, I just listed the ones that were not.
You don't need all of the things the doctor told you during discussions in your summary. Just the facts. Diagnosis: blah blah blah.
With the summary, you have a better chance of ensuring that any subsequent doctor has all of the relevant information.
Almost forgot, I did list relevant medical history. For example, an appendectomy is relevant. Some surgeons like to use the appendix for a conduit in the case of an RC. I didn't want them hunting for it since it was already gone. Other things, Like surgery for a deviated septum I left off my summary because they aren't really relevant to bladder cancer or any of its potential subsequent treatments.
Mike