Cryosurgery uses liquid nitrogen or argon gas to freeze and kill prostate cancer cells. Guided by a Transrectal Ultrasound (TRUS), the doctor places needles in pre-selected locations in the prostate gland and then dilates the needle tracks to insert thin, metal cryoprobes through the skin of the perineum into the prostate. Liquid nitrogen in the probes forms an ice ball that freezes the prostate cancer cells. As the cells thaw, they rupture. 

During cryosurgery, a warming catheter inserted through the penis is intended to protect the urethra and preserve continence. However, because the overlying nerve bundles usually freeze, most men who have cryosurgery become sexually impotent. Moreover, while cryosurgery is less invasive than radical prostatectomy, doctors know much less about its long-term effectiveness.

The most common application is localised recurrence of disease following Brachytherapy (radioactive seeds).
(The role of high-intensity focused ultrasound and cryotherapy has not yet been established and their “long term” results are uncertain).