Study: Partial Prostate Cancer Freeze Therapy Effective

But others worry the technique will miss some malignant tissue

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HealthDay Reporter

FRIDAY, April 1 (HealthDay News) -- Doctors may soon be able to treat prostate cancer more effectively and with fewer side-effects by using a new, non-surgical technique that freezes and destroys the tumor while sparing the remaining healthy gland, preliminary research suggests.

The treatment -- known as focal cryoablation -- requires inserting extremely cold gas directly into the tumor with a small needle, while the patient is under general anesthesia.

Presenting his findings Friday at the Society of Interventional Radiology's annual meeting in New Orleans, lead researcher Dr. Gary Onik referred to the treatment as a "male lumpectomy."

According to Onik, the director of surgical imaging at Florida Hospital Celebration Health, preserving much of the surrounding healthy prostate tissue and nerves means patients may avoid the sexual dysfunction and urinary incontinence that often accompanies traditional therapies, such as surgical removal, freezing and/or radiation of the entire prostate.

"These treatments have been so bad in terms of the complications they cause," Onik said. "But a majority of patients don't need their whole gland treated, so what we've finally done is give patients a middle ground. And I think the implication for men who have prostate cancer is really very profound."

Other experts weren't so optimistic about the procedure, however, concerned that focal cryoablation could leave stray malignant tissue intact within the prostate.

According to the Prostate Cancer Foundation, more than 230,000 American men are diagnosed with the disease each year, making it the most common malignancy among males in this country. While the disease is very curable if caught early, more than 30,000 men still die of the illness each year.

Onik pointed out that up to 35 percent of prostate cancer cases involve just a single, localized tumor, making pinpoint treatments like focal cryoablation feasible for many patients.

Onik's team used cryoablation to treat 42 prostate cancer patients between the ages of 55 to 75.

The men underwent the freezing technique as out-patients, typically resuming normal activities within a one-to-two-week period. Each patient was screened periodically for an average of four years after treatment.

Onik and his colleagues report that 95 percent of patients remained cancer-free upon follow-up. Additional cancer was found in a non-treated area of the prostate in three patients, who were again treated with focal cryoablation in this secondary area. All three were subsequently determined to be cancer-free at follow-up.

The Florida team also note that none of their patients experienced incontinence as a result of localized freezing, and 78 percent retained erectile function.

In contrast, Onik said his review of the available scientific literature suggests that surgical removal of the entire prostate (prostatectomy) triggers incontinence in 10 percent of patients, and sexual dysfunction in as many as 75 percent.

The Florida group plans to undertake new larger-scale studies into focal cryoablation over the coming year, while at the same time exploring a new, more accurate prostate cancer screening method designed to catch cancers currently going undetected.

Onik expressed enthusiasm that the new research would further confirm the apparent benefits of targeted freezing, in a wider group of patients.

"Focal cryoablation isn't confined to low-risk patients, so even patients with aggressive disease are eligible for this treatment," he said. "And you're not precluding using additional treatments options down the road."

He stressed that the science behind cryoablation of the total prostate is already well-established. In fact, for the past five years, Medicare has approved freezing of the entire prostate gland as both a primary and secondary treatment for prostate cancer.

"A lot of patients want the most tried and true method," he acknowledged. "But this is what I would choose if I was a patient. Not that this is not going to be controversial -- I think it will be as controversial as breast lumpectomy once was."

One of those taking issue with "male lumpectomy" is Dr. Thomas Polascik, an associate professor of urologic surgery at Duke University. Polascki expressed deep skepticism that localized freezing could be safely utilized to treat prostate cancer patients.

Onik's localized attack on prostate cancer depends on knowing exactly how widespread the cancer is, and where it is in the prostate, Polascik said. Doctors simply don't have the technology today to make those types of judgments, he added.

"The location of the biopsy doesn't necessarily correlate to where the cancer is, and the reality is that we can not predict with accuracy where the man's cancer is before treatment -- we just can't," he said. "Everyone agrees that in the future we hope to do what he's doing -- target prostate cancer and spare all the side affects. But I just dont think that we're there yet."

Dr. James McKiernan, assistant professor of urology at Columbia University Medical Center, described Onik's work as "intriguing," but he agreed with Polascik that localized freezing would most probably end up missing a lot of diseased tissue.

"With breast cancer mammograms, we have a high degree of accuracy. But prostate cancer does not have an excellent imaging technique to determine with certainty where the cancer is," McKiernan said.

"All of these cancers are microscopic -- these are not cancers that you can see or feel," he added. "I don't want to come across as overly pessimistic. I'm all for new things, and everyone wants to find a non-total treatment. But a non-total treatment needs to be totally effective. So here the side effects are lower, which is great -- but the efficacy will be lower as well."

More information

To learn more about prostate cancer, visit the Prostate Cancer Foundation.

SOURCES: Gary Onik, M.D., director, surgical imaging, Florida Hospital Celebration Health, Celebration, Fla.; James McKiernan, M.D., assistant professor, urology, Columbia University Medical Center, New York City; Thomas Polascik, M.D., associate professor, urologic surgery, Duke University, Durham, N.C.; April 1, 2005, presentation, annual scientific meeting, Society of Interventional Radiology, New Orleans.

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