Once the physician has determined that a tumor exists, the next step is to clarify the tumor's status. Fortunately, a number of systems have been developed to answer these questions. A biopsy is removed and sent to a histopathologist for examination under a microscope. The pathologist then assigns a stage and a grade to the tissue sample. The stage refers to the physical location of the tumor within the bladder or, more specifically, the tumor's depth of penetration.
Superficial tumors affect only the bladder lining.
They grow up and out from the lining tissue and extend into the bladder's hollow cavity. Invasive tumors are more dangerous than superficial tumors, since they are more likely to metastasize. The grade is an estimate of the speed of tumor growth as suggested by cell features seen under a microscope. There is a continuing debate about the classification of benign bladder lesions known as papillomas. By contrast, many pathologists and urologists classify papilloma as a Grade 1 TCC because of its tendency to recur and not to invade muscle.