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Cryotherapy, or freezing tissue to destroy tumor cells, was first developed in the 1960's. During this period, the use of "cold probes," or cryoprobes, was explored as a method to kill prostate tissue without resorting to radical surgery. Although effective in killing cancer cells, the inability to control the amount of tissue frozen during the procedure prevented broad use and development of cryotherapy for prostate cancer. These initial limitations in the application of cryotherapy continue to contribute to a lack of widespread acceptance of the procedure today.
In the late 1980's, progress in ultrasound imaging allowed for a revival in the use of cryotherapy. Using ultrasound, the cryoprobe may be guided to the targeted tissue from outside the body through a small incision. The physician activates the cryoprobe and uses ultrasound to monitor the growth of ice in the prostate as it is occurring. When the ice encompasses the entire prostate, the probe is turned off. This feedback mechanism of watching the therapy as it is administered allows the physician more precise control during application. Published studies suggest that cryotherapy may be able to deliver disease-free rates comparable to radical surgery and radiation, but with the benefit of lower rates of incontinence and mortality, shorter recovery periods and relatively minimal complications.
We developed our proprietary Cryocare technology to allow the urologist to treat prostate cancer in a minimally-invasive manner. We designed the Cryocare CS to freeze tissue much faster and with more control than previous systems.
The Cryocare CS incorporates enhanced control mechanisms to minimize the risk of unintended damage to tissue surrounding the prostate. The argon gas-based cryoprobes stop freezing instantly. During cryotherapy procedures, six to eight temperature probes are selectively placed in the prostate near the rectal tissue, sphincter muscles that control continence, and neurovascular bundles that control potency. These temperature probes enable the physician to monitor temperatures of tissue adjacent to the prostate in real-time.
To date, the majority of our cryotherapy procedures have been performed in medium to high risk patients. In these procedures, the urologist intentionally ablates the neurovascular bundles to prevent the recurrence of cancer, typically resulting in impotence. We have developed a nerve-sparing procedure for lower risk patients through a combination of early detection and improved surgical techniques. Several clinical studies are in process to determine the disease-free rates that are attainable with this procedure.
Cryoguide ultrasound planning and mapping software is a significant advancement in targeted cryoablation of the prostate. The Cryoguide software allows physicians to visualize the prostate in three dimensions and uses a grid system to facilitate the precise placement of our cryoprobes in the optimal position in the prostate. Our Cryoguide software incorporates a visualization and planning process allowing the surgeon to simulate cryoablation of the prostate. This simulation allows validation of the positioning of the cryoprobes prior to initiating treatment and tailoring the iceball formation for individual patients, thus improving patient outcomes. The Cryoguide software creates a standardized repeatable procedure and decreases procedural time.
Our proprietary cryoprobes are engineered to consistently produce sculpted ice conforming to the unique anatomy of the prostate. Our efficient argon gas-based system delivers lethal ice in a controllable and repeatable fashion. We have also developed a percutaneous access device, named FastTrac, which allows a simplified one-step insertion of our cryoprobes to significantly reduce procedure time.
We are regularly evaluating and implementing technology that will refine and improve the Cryocare Surgical System. In April 2003, we unveiled the next generation of our Cryocare technology, the Cryocare CS. The Cryocare CS is a fully integrated cryosurgical planning, placement and treatment system designed to simplify our FDA-cleared Targeted Cryoablation of the Prostate TCAP procedure. It consists of the AutoFreeze, a computer-controlled automated freezing mechanism that utilizes optimal power settings based upon target endpoint temperatures and continual feedback from the thermocouple tips. Along with AutoFreeze, Cryocare CS includes new Integrated Ultrasound technology that provides internal visualization of the prostate gland and patented CryoGuide planning software that assists physicians in determining optimal treatment of the entire gland as well as targeting specific cancerous areas of the prostate. The new system also includes a new Urethral Warmer, along with the highly successful vacuum-insulated Direct Access CryoProbes and CryoGrid, a brachytherapy-like grid fixed to the ultrasound stepper.
The Cryocare System has been cleared for marketing by the FDA. We commercially launched the Cryocare System in July 1999 following the initiation of national Medicare coverage for cryotherapy procedures as a primary treatment alternative for localized prostate cancer.
Cryotherapy is the first minimally invasive procedure that urologists can perform themselves. With radiation therapies, urologists must refer the patient for treatment to a radiation oncologist. Cryotherapy offers the urologist both the opportunity to maintain continuity of patient care and to generate additional revenue.
Our Cryocare CS System provides the following significant clinical advantages relative to other principal treatment options for prostate cancer:
Therapeutic alternatives for patients with prostate cancer have been both limited and unattractive. Current treatment options include radical surgery, radiation therapy, hormone or other ancillary therapies, "watchful waiting," and cryotherapy. These options are evaluated using a number of criteria, including the patient's age, physical condition and stage of the disease. Due to the slow progression of the disease, however, the decision for treatment is typically based upon the severity of the condition and the resulting quality of life.
Radical prostatectomy has been used for over 30 years and is most often the therapy of choice due to the surgeon's high degree of confidence in surgically removing the cancerous tissue, particularly for patients having less advanced stages of the disease. The procedure is dependent on the skill of the surgeon and is often associated with relatively high rates of impotence and incontinence and can result in operative mortality.
Radiation therapy for prostate cancer includes both external radiation beam and interstitial radioactive seed therapies (brachytherapy). External beam radiation therapy emerged as one of the first alternatives to radical prostatectomy; however, studies have shown that the success rate of this procedure is not comparable to that of radical prostatectomy. Interstitial radioactive seed therapy, also referred to as brachytherapy, is the permanent placement of radioactive seeds in the prostate. Brachytherapy has been shown to be most effective for localized tumors caught in the early stage of disease development.
Ancillary therapies, primarily consisting of hormone therapy and chemotherapy, are used to slow the growth of cancer and reduce tumor size, but are generally not intended to be curative. Ancillary therapies are often used during advanced stages of the disease to extend life and to relieve symptoms. Side effects of hormonal drug therapy include increased development of breasts and other feminine physical characteristics, impotence and decreased libido. In addition, many hormone pharmaceuticals artificially lower PSA levels in patients, which can interfere with the staging of the disease and monitoring its progress. Side effects of chemotherapy include nausea, hair loss and fatigue. Drug therapy and chemotherapy require long-term, repeated administration of medication on an outpatient basis.
"Watchful waiting" is recommended by some physicians in some circumstances based upon the relatively low risk level and slow growth rate of the disease, as well as the age and life expectancy of the patient. The aim of watchful waiting is to monitor the patient, treat some of the attendant symptoms and determine when more active intervention is required. Watchful waiting has gained popularity among those patients refusing treatment due to side effects associated with primary treatment. Watchful waiting requires periodic physician visits and PSA monitoring.
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