Cryotherapy

Cryotherapy is a method to ablate tissues by the local induction of extremely low temperatures, and has recently attracted considerable attention as an alternative, promising treatment of localized prostate (P) cancer. This paper describes fundamentals, clinical applications and future aspects of the method in the P cancer treatment in the following order: History of the therapy; Cryobiology; Cryotherapy equipment; Patient selection; Preoperative considerations; Procedure and follow-up; Complications; Outcome and prognosis; and Future development and controversies. The current, 3rd generation cryogenic machine like SeedNet (Galil Oncura) uses liquid argon as a cryogen and has needle-shaped cryo-probes to be placed in P to make conformal freezing. The salvage treatment is an alternative therapy in patient selection for those previously undergone with other treatment like radiation. In the cryotherapy procedure, the transrectal US probe is firstly inserted for guidance of the cryo-probes and other sensors. Most frequent complication involves impotence and incontinence. In reports in 1999-2007 of the primary cryotherapy, biochemical (i.e., the prostate-specific antigen (PSA) level) disease-free survivals (bDFS, in %) are 69-84, 71-89, and 45-89 in low, intermediate and high risk groups, respectively, and local recurrence (%), 10-38. For the salvage therapy in 1997-2004, bDFS are 34-72% and the recurrence, 0-23%. It seems likely that cryosurgery will play a more important role in prostate cancer management in future. (R.T.)