Cryotherapy is the controlled destruction of tissue (e. g. the prostate gland) by repeated freezing and thawing. This triggers two different processes that destroy the cells. On the one hand, this involves cell dehydration caused by extracellular icing with an accompanying increase in the intracellular concentration of salts, and on the other hand, intracellular icing. Nowadays, cryotherapy is carried out using argon and helium gases in cold and heat cycles. Similar to brachytherapy, cold probes (needles with a diameter of 1.47 mm) are transperally positioned into the prostate using a hole grid template. In the probes, argon and helium can then circulate alternately, whereby icing leads to the formation of ice through a gas expansion (the so-called Joule-Thomson effect; pressure drop causes heat loss; for example, the balloon, which is quickly emptied) at the needle tips. Due to the use of many of these very thin needles, the temperature sensors, the good adjustability of the cold and heat supply as well as the ultrasound monitoring of the freezing process, a largely even temperature distribution within the prostate can be achieved with a good separation from the surrounding tissue.
Cryotherapy, like radical surgery and brachytherapy, is a so-called local therapy and is therefore only suitable for locally limited prostate carcinomas. Some studies show that therapy successes in the short follow-up period are similar to or worse than those of surgery and radiotherapy (1,2). The disadvantage of cryotherapy is the relative frequency of urinary incontinence (up to 4.8%) and the absolute frequency of impotence (erectile dysfunction 80% after 18 and 76% after 24 months) (3.4). Due to this side-effect profile, we believe that cryotherapy is currently only suitable for secondary treatment of recurrent prostate carcinoma.
- Pisters LL et al. Salvage cryoablation: initial results from the cryo on-line data registry. J Urol. 2008 Aug;180(2):559-63
- Ng CK et al. Salvage cryoablation of the prostate: followup and analysis of predictive factors for outcome. J Urol. 2007 Oct;178(4 Pt 1): 1253-7
- Jones JS et al. Whole gland primary prostate cryoablation: initial results from the cryo on-line data registry. J Urol. 2008 Aug;180(2):554-8
- Asterling S et al. Prospective evaluation of sexual function in patients receiving cryosurgery as a primary radical treatment for localized prostate cancer. BJU Int. 2008 Sep 12. (Epub ahead of print)