The investigators hypothesize that circulating tumor cells (CTC) will be observed in patients with muscle-invasive or metastatic bladder cancer and that CTC will become undetectable, at least transiently, in a fraction of patients after treatment. To investigate this hypothesis, investigators will assess the levels of CTCs both before and after treatment. The feasibility and potential value of fluorescent in situ hybridization (FISH) in the CTCs will be assessed.

The measurement of circulating tumor cells is pursued in several cancers including breast and prostate cancer. The number of cells measured in these cancers has been shown to be prognostic. There is little information on the presence or importance of circulating tumor cells in bladder cancer. This trial is designed to determine if patients with advanced bladder cancer have circulating tumor cells and if these circulating cells are affected by treatment of the cancer.