Prostate Cancer Cryosurgery
Cryosurgery (also known as cryotherapy or cryoablation) for prostate cancer treatment is typically done when the prostate volume is 50 grams or less in size. If the prostate is larger than 50 grams, the urologist may elect to downsize the prostate prior to treatment. Three to six months prior to the prostate cryotherapy treatment, the patient may be placed on hormone therapy to block production of male hormones, therefore causing prostate to shrink. Following hormone therapy, the prostate typically will be smaller thus improving the success of the cryotherapy treatment to freeze the entire prostate.
During the minimally invasive cryotherapy procedure, multiple cryoablation needles are inserted into the prostate through the perineum (the area between the anus and scrotum). This is done with the patient under general or local anesthesia, with general anesthesia being less common choice. An ultrasound probe is inserted into the rectum to view the prostate and the entire freezing process during the cryosurgical treatment.
Cryotherapy in Prostate Cancer Patients
During cryosurgery for prostate cancer, the patient is placed in the dorsal lithotomy position. This position places the patient so that his legs are opened and lifted to a 90-degree angle. The perineum is placed over the edge of the operating table. The dorsal lithotomy position gives the doctor a clear view of the insertion for the ultra thin cryoablation needles.
While the prostate cancer cryosurgery patient is anesthetized the doctor uses ultrasound to view and as a monitor to guide the insertion of the 17g (1.47mm) cryoablation needles through the perineum into precise locations within the prostate gland. A warming catheter is used to protect the urethra from freezing since the urethra passes through the prostate gland. MTS™ (Multi-point Thermal Sensor) and thermal sensor needles keep monitor of the temperature within and around the prostate to ensure that the prostate is being frozen to temperatures less than -40⁰ Celsius while the adjacent areas of the rectum and other organs are not frozen. The use of the MTS needles to monitor temperatures of the entire prostate and surrounding tissues dramatically lowers the chance of incontinence, rectal fistulae or other side effects.
When the cryoablation needles and temperature sensors are in place, a freezing agent, argon gas, is circulated through the cryoablation needles to create temperatures of negative 40 degree Celsius or colder. Circulating the extremely cold argon gas through the cryoablation needles creates a lethally cold iceball that freezes the prostate and the cancer cells in it. Once the targeted area is frozen, the thawing is employed. The thawing process ruptures and kills the cells in the prostate gland. This is called the freeze-thaw process. This process is repeated to ensure all cancerous cells are destroyed and help stop future prostate cancer recurrence.
Throughout the cryoablation procedure, temperature sensors are used to allow physicians to determine when target temperatures have been reached. The cancer tumor and its blood supply are destroyed and the dead tissue is re-absorbed or remains in the body as harmless scar tissue.
When the freeze-thaw process is finished, the warming catheter is removed and a urinary catheter is inserted in place to help with any temporary urinary incontinence. The urinary catheter is typically removed after two or three days; unless incontinence persists.
Cryosurgery results for prostate cancer are similar to radical surgery and radiation. Read more about cryosurgery treatment success rates.