This treatment depends upon a number of technologies and these have achieved excellence in recent years. Transrectal ultrasound allows the prostate to be visualized so that the Cryo probe can be placed to allow precise delivery of super-cold temperatures, which in cryosurgery destroy prostate cancer and prostate tissues while preserving adjacent structures.
This SeedNet system consists of Cryo probes that are quite small, seventeen gauge needles that allow the delivery of the cold temperature using Argon gas, this is known as a cryogen.
This cryogen causes development of a field of cold temperature that forms an ice ball and the majority of this ice ball contains lethal ice.
This delivery system includes a template that is integrated with a template on the ultrasound screen.
The site of entry of the Cryo probes is through the perineum, or “bottom” of the patient, the needle placement using this system correlates directly with the image on the ultrasound monitor.
Argon gas passing through the needles creates the super-cold temperature at the tip of the needles and these, of course, have been precisely placed within the prostate …
the freeze as it occurs can then be monitored by observing the ultrasound image.
This is represented at it’s beginning in the image below.
An ultrasound view of the ice formation when the freeze is completed is demonstrated here.
This delivery system is precise because of advanced cryosurgical technology that is computer driven.
Cryosurgery can be used in high-grade prostate cancer and as long as the disease is confined to the prostate there clearly is potential for cure. Cryosurgery is unique in that it can be applied to patients who previously had radiation, but unfortunately the radiation failed to eliminate the cancer. This situation can usually be defined by a rising PSA, demonstrated by biopsies that are positive for cancer. Patients who are treated for failed radiation therapy are clearly at a higher risk for potential complications and failure of Cryo therapy, however cryosurgery has the potential to cure patients who have this problem. Cryosurgery can be used for patients who are poor candidates for other treatments; this includes consideration of patient age, general health, prior pelvic radiation or other concurrent diseases that make the patient a poor risk for radical prostate surgery.
Cryosurgical ablation of the prostate was first utilized in the late 1960’s, but in a format close to it’s present one since the late 1980’s. It’s availability in it’s current third generation form has been approximately four years. July 1, 1999 HCFA, the government agency that administers the Medicare program, approved the targeted cryoablation for primary prostate cancer and in December 2000 approved coverage for use of this treatment in patients who had failed prior radiation treatment for this disease.
The decision to cover cryoablation of the prostate followed studies done by Dr. Long, Bahn, Lee, and Chinn.
In the study published by Dr. Long in the journal Urology 2001, volume 57 pages 518-23 "975 patients were treated at five institutions". Comparative analysis of cryosurgery with current published data on radiation was studied, and it was determined that cryoablation was equal to or better than radiation therapy in selected patients that can be classified as low risk, medium risk and high risk.
Thermo sensors are a device that can measure temperature at the site where freezing occurs has been the latest addition to the cryoablation for prostate cancer. These sensors give accurate readings of the temperature in critical areas, for instance in the region of the shut off valve of the bladder or external sphincter. By preventing freezing in this area, we avoid problems such as loss of urinary control.
This image below demonstrates placement of the thermo censor’s Cryo probes and the subsequent freezing process that occurs during cryoablation.
Temperature monitoring is important as very cold temperatures -40 degrees centigrade are necessary for cell death, which is what we are trying to cause in the area of problem and prevent in the adjacent tissues which are important to preserve. The temperature of –40 degrees occurs inside the outer rim of the ice ball and therefore monitoring the temperature is important because the front or progressing line of freeze is not at -40 and we need to know what the temperature is in this zone.
Dr. Riemenschneider has worked with cryosurgery as it is applied it to the diagnosis of prostate cancer since 1994.There have been many technological improvements in the last eight years. The most important have been discussed, that is precise ultrasound monitoring of the freeze in measurement of the temperatures. The current technology also uses helium gas and this can be circulated through the Cryo probes to stop the freeze very precisely.
Dr. Jeffrey Cohen and Ralph Miller at Pittsburgh Allegheny General Hospital have accumulated data for the longest time period, approximately 12 years. This data clearly indicates that the cure is durable in many of the patients treated with cryosurgery for prostate cancer. The treatment can be applied in a way that allows the patient to have an easy, fast recovery and with the current technology the side effects of incontinence and rectal injury are extremely rare. Dr. Riemenschneider’s experience with this technology is not as long as some of the other experts in the field, Dr. Cohen and Dr. Miller, but after eight years of experience it is clear that this technology can be used safely and efficiently, and it does cure prostate malignancy.
The information referenced in this program was presented to the Riverside Prostate Cancer support group January 10, 2002. If you desire more information or a video reproduction of that program, please contact us at Riverside Urology, Inc. (614) 442-3000 or through this website.
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