Advanced clinical states in prostate cancer.

The classification of clinical disease states within advanced prostate cancer is set apart from other solid tumors largely through measurement of prostate-specific antigen in the blood. This testing has allowed the distinction between the castration-sensitive and the castration-resistant states, to complement radiographic distinction within advanced prostate cancer. This has paved the way for advances in prognostication and treatment of patients within a heterogeneous disease group. Currently used clinical classifications have limitations and continue to evolve. The authors define the current disease states and discuss implications for prognosis and treatment decisions, as well as the limitations of existing classifications and emerging discoveries.