HIFU Non-Inferior to Prostatectomy for Localized Prostate Cancer

SAN ANTONIO — A comparison of high-intensity focused ultrasound (HIFU) and radical prostatectomy (RP) found that HIFU was non-inferior to surgery as primary treatment for localized prostate cancer, according to a French trial.

At a follow-up of 30 months, patients treated with HIFU had a significantly higher salvage treatment-free survival rate than patients who underwent RP (89.8% vs 86.2%, HR 0.76, 95% CI 0.61-0.96, P=0.008), reported Pascal Rischmann, MD, PhD, of Toulouse Academic Hospital in Toulouse.

Results were similar when adjusted for age and other covariates at baseline, including BMI, American Society of Anesthesiologists physical status score, Prostate volume, PSA level, and grade group (HR 0.71, 95% CI 0.52-0.97, P=0.03).

Moreover, patients treated with HIFU had better functional results regarding urinary continence and erectile function, Rischmann observed.

This is the first prospective study comparing HIFU and RP as a primary treatment for localized prostate cancer grade group 1 and 2, Rischmann said during a plenary session at the American Urological Association annual meeting. “Salvage treatment-free survival after HIFU was not inferior compared to radical prostatectomy.”

The HIFI study was a non-inferiority, prospective, non-randomized study performed in 46 centers across France from April 2015 through September 2019. The trial included a total of 3,328 patients, 1,967 of whom were treated with HIFU and 1,361 underwent RP.

Patients were eligible for the study if they had low- or intermediate-risk prostate cancer (PSA <15 ng/ml, Gleason score ≤3+4, and clinical stage T1-2 NxM0), a maximum of four sextants invaded out of six on multiparametric MRI, a minimum age of 70 for HIFU patients, and a life expectancy of 10 years for RP patients.

HIFU was delivered using the Focal One device, with treatment limited to 70% of the prostate gland.

Patients in the HIFU arm (n=1,967) had a median age of 74.7, while those in the RP arm (n=1,361) had a median age of 65.1. The median baseline PSA was 7.1 in the HIFU arm and 6.93 in the RP arm. Most patients had intermediate-risk disease (60% in the HIFU arm, 63% in the RP arm), and the two cohorts were evenly split between patients classified as grade group (GG) 1 and those >1.

Overall survival was 97.7% in the HIFU arm and 99.5% in the RP arm, but there was no significant difference between the two groups after adjusting for age (HR 2.53, 95% CI 0.95-6.73, P=0.064).

Cancer-specific survival was 100% in both arms, and no deaths were attributed to treatment.

Of those patients in the HIFU arm, 10% eventually underwent salvage treatment, 5% underwent second HIFU, and 2% went on active surveillance. In the RP arm, 13% underwent salvage treatment and 2% went on active surveillance.

Regarding safety, complications greater than IIIa were reported in 2.7% and 2.1% of patients after HIFU and RP, respectively.

As for functional results, urinary incontinence and erectile dysfunction “were significantly lower after HIFU,” Rischmann reported.

Specifically, at 12 months, 64% of patients who underwent HIFU had a stress incontinence score of 0 (indicating the patient had no or very mild urinary continence symptoms) compared with 48% of patients in the RP group (risk ratio 0.76, 95% CI 0.70-0.83, P<0.001).

At 30 months, 62% of patients in the HIFU arm had normal to moderately impaired erections compared to 42% of patients in the RP arm. “So there was significantly less degradation for erectile function after HIFU,” Rischmann observed.

International Prostate Symptom scores were in the mild range for both HIFU and RP, and despite the difference in age between the two groups, there was no statistical difference in quality of life scores.

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