Fish Testing

My father has grade 3 superficial bladder cancer. He has just finished his round of six bcg treatments. I read and article in The Journal of Urology about a FISH test. I will be asking our doctor to perform this test while doing his biopsy this week. It states that this test is a pretty accurate test in determing which tumors will spread into the muscle and which wont. Does anyone have any more information on this test?