April 3, 1998
--------------------------------------------------------------------------------
Technology
Cryomedical Sciences works to put tumors on ice
by Bob Mentzinger
Behold the malignant tumor.
It likes your body, the cells it produces, the supply of nourishing blood. It especially likes your warm, constant internal temperature.
It should be no surprise, then, that cryosurgery -- the use of extreme cold to destroy cells -- is gaining converts within the medical community for a widening range of cancer treatments.
While cryosurgery has been used for decades to treat external tumors, physicians -- thanks in part to new technologies from Cryomedical Sciences Inc. of Rockville -- increasingly are using it inside the body.
"This is truly the dawn of a new age in the understanding of molecular mechanisms activated during cryosurgery," said John Baust, Ph.D., Cryomedical Sciences's chief scientific officer.
Dr. Reinhardt Schindler, a retinal surgeon at Washington Adventist Hospital in Takoma Park, has used cryosurgical devices like those developed by Baust's company for decades to repair sensitive inner-eye membranes.
"The technology is something that's been around for 20 or 30 years," Schindler said. "But the devices really are getting easier to use."
First proven effective for retinoblastoma (a childhood cancer of the retina) and early-stage skin carcinomas, cryosurgery also is used to treat precancerous skin growths and intraepithelial neoplasia -- a precondition of cervical cancer.
Traditional cryosurgery meant applying liquid nitrogen at a temperature of -320.8 F directly to cancer cells with a cotton swab or spraying device. But inside the body, nitrogen is circulated through a "cryoprobe" placed in contact with the tumor.
Using ultrasound pictures, doctors direct the cryoprobe and monitor cycles of freezing, thawing and refreezing meant to achieve "apoptosis," or controlled cell death.
Cryosurgery's advantage: It's less invasive than traditional surgery, involving only a small incision and insertion of the cryoprobe through the skin. Since physicians can focus their treatment, healthy tissue nearby is spared and fewer complications like pain or bleeding can result.
Cryosurgery also requires a shorter hospital stay and recovery time. The process can be used repeatedly and in tandem with surgery, chemotherapy and radiation. And it offers an option for inoperable or unresponsive cancers. The procedure is done thousands of times per year in hospitals and clinical centers in all 50 states, and in 140 cryosurgical "centers of excellence" that Rockville's Cryomedical helped establish through its research and development.
The major disadvantage of cryosurgery is its uncertain long-term effectiveness. While cryosurgery may be effective in treating visible tumors, it may miss microscopic cancer spread. Because its effectiveness is debated, insurers often balk at coverage.
But research continues, and doctors now are aiming cryoprobes at prostate and liver cancer.
The National Cancer Institute in Bethesda reported cryosurgery can be used in "early-stage cancer confined to the prostate gland," but only when "standard treatments are unsuccessful or impractical." It also posited whether long-term incontinence and impotence can result.
With liver cancer, cryosurgery is an attractive possibility since that organ is a mass of highly vascular tissue that often makes surgical removal impossible or difficult. The side-effects "may be less severe than those associated with surgery or radiation therapy," according to the NCI report, and may be only temporary.
Observers agree the expanding use of cryosurgery for internal tumors has been one of the more promising technological advances in cancer treatment research, made possible, in part, by products like CMS's Cryo-lite, a handheld device that looks a little like a revolver.
The $1,000 device, designed for use in outpatient clinics, uses external "packets" of four supercold cryogen materials -- carbon dioxide, nitrous oxide, argon and liquid nitrogen -- each with different temperatures specific to various clinical applications. An external source allows for extended freeze times.
The company's patented technology "reduces overall procedure time while ensuring optimal tissue destruction," according to Baust. The device's "user-friendly freeze/thaw controls" provide for all-important manipulation of a tumor during treatment cycles.
Where the Cryo-lite is "a low-capacity device for focused, in-office applications," the company has made its reputation by manufacturing and shipping 175 of its "AccuProbe" products, primarily to medical schools and teaching hospitals across the United States, since 1991.
Those units, which sell for $200,000, are found solely in operating rooms and use liquid nitrogen exclusively to provide the "greatest cooling capacity of any device available," Baust said.
Baust credits developments in ultrasound as much as his own technological savvy for the upswing of interest in cryosurgery.
"It's been done since the late '60s or early '70s," Baust said. "But it was a little ahead of its time." At the time, cryosurgery involved surgeons "placing large, bulky probes based on where they thought the tumor was, and then, 'Well! Let's see how we did!'"
But the half-inch probes have been reduced to "the size of a refill of a ballpoint pen," Baust said.
Meanwhile, huge advances in imaging and minimally invasive surgical techniques have allowed surgeons a better look at what they're working on.
"We had a good car, but now we have a good traffic system, a set of eyes that can look into the organ being frozen," he said.
Cryomedical Sciences's staff of 34 conducts all research, development, administration and manufacturing in Rockville, with sales -- about $2.2 million in 1996 -- handled by a network of independent distributors.
--------------------------------------------------------------------------------
HOME | NEWS & VIEWS | ENTERTAINMENT | CLASSIFIEDS | SHOPPING | ARCHIVES | GAZETTE INFO | SITE INDEX
|
