I sympathize with your anxiety but I believe you will actually feel better once you know what it going on aside from "large tumor". I have known people with larger tumors that turn out to be non-aggressive and non-invasive, bladder tumors come in many different types, shapes and sized. The large majority of bladder tumors are non-invasive, something like 3 out of 4, so the odds are still on your side that this could be treatable with removal only, perhaps no further treatment will be needed if it is a Grade I tumor.
Uros can tell when something is a cancerous tumor, but they can't be sure of the exact grade and stage, which is the most important factor, until the biopsy. Experts are good at judging, according to a research study by Dr. Herr they were right 94% of the time, but....that study was looking at people who had been already diagnosed and had recurrences. So they were making those judgments with previous knowledge of the patient's history etc....so it's not an exact science by any means and biopsies are the backbone of treatment decisions.
Just because the tumor is relatively large doesn't mean it has been around for many years nor that it will necessarily be aggressive, as Joe's was.
Please take care of yourself, try to spoil yourself as much as you can during this difficult time.. Do what ever you need to do to help yourself stay sane until you know the whole story.
Wendy