Optional Treatments


Cryotherapy is the use of extreme cold produced by liquid nitrogen or argon gas to destroy a targeted tissue. It is based on the Joule-Thompson effect when high pressure Argon is allowed to flow through the cryoprobe [hollow needle] (picture 65), as it expands at the tip, it generates an extremely cold temperature and an ice-ball (picture 66). Cryotherapy has 3 main effects: 1) intracellular ice formation (protein denaturation), 2) extracellular ice formation and 3) ischemia (picture 67). The combination of these 3 effects leads to a tissue necrosis. Cryotherapy has various applications in the medical field from painkiller to muscular spam, oncology and Parkinson.

Picture 65 : The Joule-Thompson effect

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Picture 66 : The production of iceball at the tip of cryoprobes

Picture 67: Biological effect of cryotherapy on cells and targeted tissue


Under ultrasound-guided vision, cryoprobes are placed transperineally into the prostate under general anesthesia. Once all the needles in place, the ablation protocol consists on a Freeze-thaw cycle as follows : 10mn freeze / 10mn thaw / 10mn freeze / 10mn thaw for a total ablation time of 40 minutes (picture 68). The whole procedure is monitored in real-time with a complete control of the freezing process. The goal is to reach – 40°C in the targeted zone to ensure ablation and above 0°C in zones with sensitive structures to ensure their preservation. To avoid complications the use of an urethral-warming catheter and intra-rectal warming source is necessary. The success of a procedure depends on nadir temperature, freezing duration, number of freeze-thaw cycles, and rate of thawing. In terms of safety/accuracy of the procedure the blurred lines of cooling/heating between the cryoprobes on one side and the warming disposables on the other side are one of the technical difficulties to improve in the treatment of localized prostate cancer.

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Picture 68 : Sagittal view of a cryotherapy procedure with intraprostatic iceballs


As for HIFU, the indications of cryotherapy in prostate cancer are mainly low-risk and intermediate-risk but also selected high-risk patients (see “Clinical Scenarii”) are treated either focally or radically. Cryotherapy is proposed to naïve prostate cancer as well as in salvage situation after a radiotherapy or an HIFU failure.


One of the most recent well-conducted study on a midsize population (n=122) of mainly Intermediate Risk (89%) and Low Risk (10%). At 3 years follow-up 10% of the patients needed to convert to a radical treatment, none were using pads and 84% conserved the erectile function when the patients were potent before. In this study they were no results regarding the negativation of the biopsies in the targeted area [33]. In the COLD registry published by J. Ward in 2011 on a population of 1160 patients based on a sampling of 14% of the total population who underwent prostate biopsies control 6 months after cryotherapy 74% of the patients had negative biopsies [34].