Jessica, I have not had experience with coumadin or similar with bladder cancer biopsies, but have with other more invasive surgeries. It is standard procedure to take the patient off blood thinners (even aspirin) prior to anything that could bleed. Your father's physicians are aware of the issue and will act and advise accordingly. It should not cause problems.
Sara Anne
Diagnosis 2-08 Small papillary TCC; CIS
BCG; BCG maintenance
Vice-President, American Bladder Cancer Society
Forum Moderator