Cryotherapy is a technique by which tissue is frozen in order to treat certain conditions. It is most commonly employed to destroy (ablate) tumors and therefore, is usually referred to as cryoablation. The process is based on scientific findings that freezing cells to -40° C/F * causes those cells to die. In urology, genital warts have been treated for years with this technique. In the last 15 years, cryoablation has been used to treat prostate cancer and kidney cancer.

Cryoablation of the prostate was first used in the 1970’s as a “salvage” therapy for men who had failed radiation as a primary treatment of their prostate cancer. Since then, the technology has changed greatly and cryoablation of the prostate is now considered one of several first-line treatment options for men with localized prostate cancer. The technique is performed under anesthesia using needles passed through the skin of the perineum (the area below the scrotum and above the anus). Each needle has the ability to freeze or thaw tissue. The goal of cryoablation of the prostate is to freeze the entire prostate from base to apex, top to bottom, and right to left. The only portion of the prostate which is spared is the urethra passing through the middle of the prostate. The urethra is actually warmed during the procedure with a warming catheter. Typically, 6 to 8 freezing probes (needles) are passed into the prostate and then 5 to 6 smaller temperature probes placed strategically around the prostate to ensure that the desired temperatures are achieved. Two complete freeze/thaw cycles are employed to increase the chances that every last cancer cell has been treated. The cells die and are reabsorbed over the subsequent months. The body usually does this in a “non-inflammatory” way which means there is typically no pain associated with the process. The residual prostate is much reduced in size and often is difficult to feel on rectal exam. The beauty of cryoablation of the prostate is that there is little collateral damage to the surrounding tissue (i.e. bladder and rectum) since structures within millimeters of a lethal freeze are subjected to a non-lethal freeze. The significant down-side to cryoablation of the prostate is that the nerves that allow a man to have erections are injured almost 100% of the time as they course along the prostate, resulting in erectile impotence. The size of the prostate is generally the limiting factor as to whether cryoablation can be performed. If the prostate is too large it will be obscured by the boney pubic arch which limits the placement of the needles.

Cryoablation of the kidney is a relatively new treatment option for tumors of the kidney. For smaller lesions, destroying the tumor by freezing allows for preservation of the unaffected portion of the kidney. The procedure is typically done laparoscopically (using small incisions to pass scopes and instruments into the body cavity) or percutaneously (passing the probe through the skin into the tumor directed by CT scan). Most cryoablations of kidney tumors utilize a single probe although larger tumors can require several probes to get an adequate freeze. Because neither the extent nor the temperature of the freeze can be determined exactly, cryoablation is not considered the “gold standard” for treatment of renal tumors unless there are extenuating circumstances such as the patient’s poor health.

* -40° F and -40° C are equivalent