ANAHEIM, Calif.—Cryoablation is at least as effective external beam radiation therapy (EBRT) for treating localized prostate tumors, according to the first North American randomized clinical trial comparing the two therapies.Five-year survival rates were 89.7% for the cryoablation-treated patients and 88.3% for the men treated with EBRT, investigators reported here at the American Urological Association annual meeting. After 36 months of follow-up, only 6.6% of the cryoablation patients had positive biopsy findings compared with 26.3% of patients who underwent EBRT.

“This study demonstrates that cryoablation is equivalent to external beam radiation when used to treat localized prostate cancer,” said Bryan Donnelly, MD, clinical assistant professor of urology at the University of Calgary in Canada.

“Furthermore, the positive biopsy rates three years after treatment were significantly higher for patients who underwent radiation therapy. Like radiation therapy, cryoablation is a treatment option that should be considered by all patients who are diagnosed with localized prostate cancer.”

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The researchers randomly assigned 244 men (mean age 69 years) with localized prostate cancer to undergo one of the two treatments. Inclusion criteria included histologically proven prostate adenocarcinoma, stage T1, T2 or T3 disease, and no evidence of nodal or distant metastases.

The median duration of follow-up was 82 months (range 47 to 110 months). Six patients were lost to follow up. The primary end point was biochemical failure, radiologic evidence of disease, or initiation of additional prostate cancer treatment 36 months after their procedure.

Fifty-seven men experimented treatment failure, 25 in the cryoablation arm and 32 in the EBRT arm. In the cryoablation arm, biochemical failure occurred in 24 men and radiologic (positive bone scan) in one man.

In the EBRT arm, 21 had biochemical failure, one had radiologic failure, and 10 required additional treatment (salvage cryoablation for eight patients and hormone therapy for two). Overall survival between the two treatment arms was not statistically different.

“This is reassuring news. The findings clearly show that cryoablation is at least as good as radiation. So, there are no reasons why it should not be equally accepted,” Dr. Donnelly told Renal & Urology News. “Cryoablation is easy to do and the cheapest treatment to go through so it could mean a cost savings and less morbidity.”