Cryotherapy Freezes Out Tumors, Leaves Rest of Prostate
Daniel J. DeNoon
WebMD Health News
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Reviewed By Louise Chang, MD
The suggestion comes in a presentation to this week's meeting of the Society of Interventional Radiology by Gary M. Onik, MD, director of the Center for Safer Prostate Cancer Therapy and professor of radiology at the University of Central Florida, Orlando.
It's not exactly a new technique. Onik has been exploring its use for more than a decade in men whose prostate cancer has not spread beyond the prostate gland. Now he's collected data on 120 men with prostate cancer who underwent the procedure up to 12 years earlier.
"We've reached a tipping point," Onik says in a news release. "Treating only the tumor instead of the whole prostate gland is a major and profound departure from the current thinking about prostate cancer."
In this way, the technique is similar to lumpectomy for breast cancer. Doctors at first scoffed at the idea that anything short of total mastectomy would be an appropriate cancer treatment. But with careful patient selection and better tumor mapping, lumpectomy has become the treatment of choice for many women with breast cancer.
"I think it is time for men to consider this," Peter Nieh, MD, director of Emory University's Uro-Oncology Center. Nieh reviewed the Onik study for WebMD but was not involved in the study.
Nieh says the idea of leaving prostate tissue behind is so different from standard treatment that it seems "crazy" at first. But it makes sense, he says, when one considers that there are very few cancers in which the entire organ is removed.
"The technique is still not mainstream. You'll hear the criticism that it's not appropriate for all patients," Nieh says. "But when you see how many patients get radical prostate surgery, and multiply that by the 40% who would never die of prostate cancer, that is a lot of patients getting over-treated for what they have."
Onik's data are compelling. Of the 120 patients, 93% are cancer-free an average of 3.6 years after treatment.
The most feared side effects of radical prostatectomy and radiation therapy are incontinence and sexual dysfunction. In Onik's study, none of the men became incontinent and 85% of patients remained sexually potent.
Yet, Nieh says, long-term data on focal cryotherapy remains skimpy. That's reflected in the American Urological Association's 2008 "Best Practice Policy Statement" on cryotherapy.
"This procedure may fill a void in the therapeutic options available to men ... However, current data are insufficient to determine the incidence or consequence of treatment failure," the statement notes.
One advantage to cryotherapy is that if prostate cancer returns, the procedure can be repeated. That's usually not an option after surgery or radiation therapy.
Better Biopsy for Prostate Cancer?
Onik says that one of the keys to successful cryotherapy is a new technique that allows doctors to pinpoint the location of prostate tumors.
That's important for focal cryotherapy, which uses thin needles that inject tumors with freezing gas.
Onik's technique piggybacks on a technique used for brachytherapy, a prostate cancer treatment option in which radioactive beads are implanted in the prostate. Onik places a grid similar to that used in brachytherapy over the perineum -- the area between the scrotum and the anus -- and takes up to 50 tiny needle samples of the prostate.
This technique is less likely to cause infection than the most common prostate biopsy technique, in which doctors approach the prostate through the rectum.
In his conference report, Onik says his trans-perineal biopsies found things that would have been missed by the trans-rectal approach in 70% of patients.
Nieh says the trans-rectal approach is more accurate than Onik makes it sound. But he agrees with Onik that the newer technique is less likely to result in infection. And, given the increasing rate of antibiotic-resistant infections in patients undergoing prostate biopsy, Nieh says this is a major advantage to Onik's approach.
SOURCES: 34th Annual Scientific Meeting of the Society of Interventional Radiology, San Diego, March 7-12, 2009. News release, Society of Interventional Radiology. Peter Nieh, MD, associate professor of urology and director, Uro-Oncology Center, Emory University, Atlanta. American Urological Association, Journal of Urology, November 2008; vol 180: pp 1993-2004.
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