Procedure involves freezing tumor rather than removing entire gland
A new procedure for prostate cancer that destroys only the part of the gland that is cancerous results in fewer side effects than surgery or radiation therapy, a new study finds.
The so-called “male lumpectomy” is a minimally invasive procedure that freezes part of the prostate. The study suggests that it might prove especially beneficial for men who have local prostate cancer or those for whom radiation has not worked.
“This is a new paradigm where instead of treating the whole gland, you just treat the cancer,” said study author Dr. Gary M. Onik, director of the Center for Safer Prostate Cancer Therapy in Orlando, Fla. “We have shown that you have the same advantages in the local treatment of prostate cancer that women have found with local treatment of breast cancer.”
In most cases, Onik said, just the cancer — not the entire prostate gland — needs to be removed. “You will get as good, if not better, results with a fraction of the complications,” he said.
And the procedure virtually eliminates incontinence and impotence, Onik said.
An American Cancer Society representative, however, questions whether the method has been sufficiently studied to recommend it as a treatment.
The results of the study were presented Monday at the Society of Interventional Radiology’s annual meeting in San Diego.
For the study, Onik used the freezing technique, called cryoablation, to treat 120 men with prostate cancer. In the procedure, a probe is inserted through the skin, and a doctor uses imaging to guide the needle to the tumor. Once at the site of the tumor, the probe circulates cold gas to freeze and destroy the cancerous tissue.
During an average follow-up of about 3½ years, 112 men showed no recurrence of cancer, though 72 of the men were at high risk of having their cancer recur, Onik said. None of the men reported incontinence, and 85 percent of the men who were potent before the procedure maintained that potency, he noted.
The best candidates for the procedure, Onik said, are men with minimal disease who usually don’t receive treatment but are monitored. In addition, men who have failed radiation treatment are good candidates, as are men with more severe localized cancer, he said.
Dr. Durado Brooks, director of colon and prostate cancer prevention programs at the American Cancer Society, expressed concern that the freezing technique has not been studied enough to recommend it as a treatment for prostate cancer.
The men who underwent cryoablation were only followed for a few years, he noted. “A lot of the problems, particularly the recurrence of cancer, are in a five- to 10-year window,” Brooks said, adding that data are needed on how many of the men treated with cryoablation see a recurrence of their cancer.
“The study does lend some additional credence to the potential value of cryoablation, as long as men recognize that there are significant limitations,” Brooks said. “The main one being, we don’t have as nearly as long a history on cryoablation as we do on either surgery or radiation treatment.”
Also at the meeting, Onik was expected to present the results of another study that used a 3-D biopsy method to identify the extent and grade of prostate cancer. The 3-D method is a correlate to the “male lumpectomy,” because it proved to be more accurate in locating the exact site of the tumor, he said.
In the study, 180 men who’d had a standard biopsy underwent 3-D biopsy. The study found that 70 percent of the men would have their prostate cancer treatment changed by the information gleaned from the 3-D procedure.
For example, more than 50 percent of the men whose standard biopsy found prostate cancer on one side of the prostate also had cancer on the other side of the prostate, which was found only by the 3-D biopsy.
For the procedure, a grid is placed over the skin between the rectum and the scrotum, allowing a doctor to accurately map the location of each biopsy core that is removed. The grid is more precise in determining the exact location of cancer, Onik said.
Brooks said that, of the two procedures, “the 3-D prostate mapping biopsy is probably closest to having a clinical impact.”
“It makes you wonder,” Brooks added, “if these findings are replicated by other studies, how many men are being significantly under-treated?”