Cryosurgical ablation of the prostate for prostate cancer: Background, technique, and results

A number of efforts are underway to expand the armamentarium available for the treatment of cancer beyond the traditional three pillars of surgery, chemotherapy, and radiation. One area of active investigation involves an old idea, namely the destruction of tumor tissue using the cytotoxic effects of extreme cold. The therapeutic use of the application of extreme cold for the treatment of disease may be generally termed cryotherapy. Cryosurgery is a form of cryotherapy that focuses on the destructive response to cold and is based on using freezing temperatures to elicit necrosis in tissues exposed to a severe cryogenic injury. Cryodestruction is thought to occur on two levels, causing cellular injury as well as vascular injury and large-scale injury.Mechanisms of immediate, direct cell injury caused by freezing include protein and lipid stress; failure of cell metabolism; shifts in osmolality; formation of crystal ice, which disrupts organelles and membranes; cell shrinkage and expansion; thermomechanical shear stress; and recrystallization during thawing and membrane rupture. On the macroscopic level, delayed injuries occur secondary to vascular damage, microthrombi and tissue ischemia, and increased capillary permeability, which become apparent in tissue 4 to 10 days postsurgery.