Biophysiologic considerations in cryoablation: a practical mechanistic molecular review.

Cryotherapy techniques date back as far as the mid-1800s, when James Arnott demonstrated the effectiveness of salt/ice mixtures in palliation of breast, uterine, and skin cancers. Subsequent advances saw the use of liquid air and solid carbon dioxide in the treatment of various conditions, particularly benign dermatologic lesions (1). Cooper and Lee introduced the first automated cryosurgical apparatus cooled by circulating liquid nitrogen in 1961 and initially used it for treating neuromuscular disorders (2). Liquid nitrogen probes were soon being used in the treatment of benign prostatic hypertrophy and prostate cancer, though complications were quite common, resulting in the procedures falling out of favor until the 1990s, when intraoperative ultrasound techniques were developed, allowing more accurate monitoring of the freezing process (1). The advent of "third-generation" argon and helium gas probes in 2000 and preoperative computer thermal mapping techniques have allowed even more precise placement, temperature control, and further reduction in post-procedural morbidity (3). Cryosurgical techniques are currently used to treat a wide variety of conditions, but significant urologic indications include treatment of low and intermediate risk prostate cancer and renal cell carcinoma < 4 cm in diameter.