Cryoablation is a process that uses extreme cold (cryo) to remove tissue (ablation).
Cryoablation is used in a variety of clinical applications using hollow needles (cryoprobes) through which cooled, thermally conductive, fluids are circulated. Cryoprobes are inserted into or placed adjacent to tissue which is determined to be diseased in such a way that ablation will provide correction yielding benefit to the patient. When the probes are in place, the cryogenic freezing unit removes heat (“cools”) from the tip of the probe and by extension from the surrounding tissues.
Ablation occurs in tissue that has been frozen by at least three mechanisms: (1) formation of ice crystals within cells thereby disrupting membranes, and interrupting cellular metabolism among other processes; (2) coagulation of blood thereby interrupting bloodflow to the tissue in turn causing ischemia and cell death; and (3) induction of apoptosis, the so-called programmed cell death cascade.
The most common application of cryoablation is to ablate solid tumors found in the lung, liver, breast, kidney and prostate. The use in prostate and renal cryoablation are the most common. Although sometimes applied through laparoscopic or open surgical approaches, most often cryoablation is performed percutaneously (through the skin and into the target tissue containing the tumor).
Prostate cryoablation is highly effective but, as with any prostate removal process, also can result in impotence. Prostate cryoablation is used in three patient categories: (1) as primary therapy in patients for whom sexual function is less important or who are poor candidates for radical retropubic prostatectomy (RRP, surgical removal of the prostate); (2) as salvage therapy in patients who have failed brachytherapy (the use of implanted radioactive “seeds” placed within the prostate) or external beam radiation therapy (EBRT); and (3) focal therapy for smaller, discrete tumors in younger patients.
Renal cryoablation is highly effective in smaller tumors found in the kidney and adrenal gland. The results are excellent and spare surrounding tissues from ablation.