Cryoablation Shows Efficacy for Prostate Cancer
J. Stephen Jones, MD, FACS
The technique is associated with a low rate of biochemical recurrence and minimal urinary morbidity, based on data from 3,209 patients who underwent primary cryoablation at a number of medical centers nationwide. The data are stored in the Cryo On-Line Database (COLD), which is sponsored by Endocare, a company that makes cryotherapy devices. The registry is overseen by a board of eight urologists with independent control of data and publication.
Maturing data demonstrate disease control comparable to published findings for other forms of therapy, said primary investigator J. Stephen Jones, MD, Chairman of the Cleveland Clinic Health System Department of Urology, Glickman Urological & Kidney Institute, in Ohio.
Patients had a median age of 70 years, and 76% had intermediate or high-risk disease according to the D'Amico risk-classification scheme. Median follow-up was 1.5 years, with more than 300 subjects having follow-up in excess of five years.
The overall five-year actuarial biochemical disease-free survival (bDFS) was 77% using the American Society of Therapeutic Radiology and Oncology (ASTRO) definition of three consecutive rises in PSA after the post-treatment nadir backdated to the midpoint between the nadir and the first rise.
The five-year bDFS was 67% using the Phoenix definition, which is the nadir PSA plus 2 ng/mL. The risk-stratified, five-year bDFS was 80%, 77.5%, and 77% for patients with low-, moderate-, and high-risk disease, respectively, using the ASTRO definition and 82%, 68%, and 54% using the Phoenix definition.
Of 1,848 patients who did not have urinary incontinence at baseline, only 41 (2.2%) reported any urinary leakage at 12 months after treatment. Only 30 (0.9%) of the 3,209 men had urinary retention at 12 months.
Additionally, of 548 patients potent prior to treatment, 181 (33%) were able to have intercourse at 12 months. Only 11 patients in the entire cohort (0.3%) had rectal fistulas between six weeks and 12 months postoperatively.
These results are limited by the retrospective nature of a registry, Dr. Jones observed, but are robust because of the large number of patients and the diverse practice patterns in academic and community settings.
“These data demonstrate that cryotherapy can provide outcomes with disease control and morbidity comparable to surgery and radiation. [The findings] are especially robust regarding morbidity, which is low for all outcomes except sexual function,” Dr. Jones said. He and his colleagues reported study findings here at the American Urological Association Annual Meeting.
He cautioned that disease-control data are limited to about five years' follow-up. Going forward, he said, one of the primary goals in following these men is to learn as much as possible about late outcomes. Pending such long-term data, surgeons today typically use cryotherapy in patients older than 65 years and those for whom sexual function is not a priority.
“Cryotherapy as practiced in 2009 is associated with very low rates of urinary and GI morbidity,” said Dr. Jones, who is a paid proctor for Endocare. For the sexually inactive man, cryotherapy is a reasonable alternative to radiation and essentially has no reported late complications.
He added that focal cryotherapy may overcome the high risk of sexual side effects, and investigators are actively but cautiously exploring its potential.