Focal cryo vs. focal HIFU: Similar oncologic outcomes

London-Oncologic outcomes are similar using focal cryotherapy and focal high-intensity focused ultrasound (HIFU) for treatment of localized prostate cancer, French urologists reported at the World Congress of Endourology and SWL in London.  

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Their study analyzed prospectively collected data from patients who were followed for at least 1 year after being treated with focal therapy through the Paris-based Institut Mutualiste Montsouris (IMM) department of urology. Control biopsies were obtained routinely at 1 year in all patients and then after 2 or 3 years, regardless of PSA, according to the treating physician’s discretion.

There were 91 men who had undergone focal cryotherapy and 58 who had focal HIFU. Median follow-up was 22 months for the cryotherapy group and 19 months for HIFU patients. Any positive follow-up biopsy was considered treatment failure, and it was found in 43 men (47%) who had cryotherapy and 18 of the men (31%) who had HIFU. The difference in rates was not statistically significant.

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In the cryotherapy and HIFU groups, the positive biopsy was ipsilateral in 14 (15.4%) and eight (13.8%) men, respectively; contralateral in 14 (15.4%) and seven (12.1%) men, respectively; and bilateral in 15 (16.5%) and three men (5.2%), respectively. Fifteen men in the cryotherapy group and four in the HIFU group had a Gleason 7 positive biopsy and underwent salvage radical prostatectomy. Thirteen cryotherapy patients and three HIFU patients had one ipsilateral Gleason 6 positive biopsy. Of those 16 patients, nine underwent repeat focal therapy and seven chose active surveillance.

Next: "Our experience indicates that failure rates are comparable after focal cryotherapy and focal HIFU."

“Although an increasing number of men with prostate cancer are opting for active surveillance, less than 8% of those with even low-risk prostate cancer who would be candidates for active surveillance are choosing that option. Focal therapy has emerged as a halfway measure between active surveillance and radical treatment, and may particularly be of interest for men who would rather have some form of treatment,” said first author Youness Ahallal, MD, a urologist at IMM.

“There are currently four energy modalities for performing focal therapy. Our experience indicates that failure rates are comparable after focal cryotherapy and focal HIFU. However, the results need to be interpreted with the understanding that men were not randomized to treatment, we were not able to control for tumor volume, and follow-up is still short-term,” Dr. Ahallal said.

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The 149 men included in the analysis were identified from among the 277 patients with prostate cancer who underwent some form of focal therapy at IMM between January 2009 and July 2014. Diagnostic biopsies are performed with a transperineal grid-guided technique and include at least 20 cores, depending on the size of the prostate. Transrectal ultrasound and MRI-targeted biopsies are performed for follow-up after focal therapy.

If a follow-up biopsy is positive, focal therapy is carried out if there is only one positive biopsy in the same lobe. Otherwise, the French team opts for active surveillance, androgen deprivation therapy, or salvage robot-assisted radical prostatectomy, depending on the disease characteristics.

Next: Majority of patients had Gleason 6 disease

Majority of patients had Gleason 6 disease

In the cohort analyzed for this study, mean age at the time of the focal treatment was 65 years for the cryotherapy group and 64 years in the HIFU group. The cryotherapy and HIFU groups were also similar in baseline disease characteristics. Mean PSA was about 6.3 ng/mL, and the majority of patients in the cryotherapy and HIFU groups had stage T1c (86% and 82%, respectively) and Gleason 6 (3+3) disease (82% and 91%, respectively). Median serum PSA nadir values after treatment were 2.9 ng/mL in the cryotherapy group and 3.6 ng/mL among the men who had HIFU.

Responding to a comment about the high proportion of patients in the HIFU group who had Gleason 6 disease (91%), Dr. Ahallal noted that many of the men in the study were enrolled early when focal HIFU was first being used, and at that time clinicians were being very cautious in selecting patients for focal versus radical therapy.

“In our initial experience, men were considered candidates for focal therapy if they met D’Amico criteria for being low-risk and their disease was unilateral with three or fewer positive biopsy cores,” he said.

“Our aim now is to try to expand the indication for focal therapy to patients with higher volume Gleason 6 disease or Gleason 7 (3+4) prostate cancer that might be less likely to be referred for active surveillance.”

The investigators have previously published data on the morbidity of all forms of focal therapy for localized prostate cancer (Eur Urol 2013; 63:618-22). They reported a <2% rate of major complications and no apparent differences in treatment-related complications between focal cryotherapy and focal HIFU.

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