HIFU Study Makes Case for Role in Prostate Cancer Subgroup

Pascal Rischmann, MD, PhD

Treatment with unilateral high-intensity focused ultrasound (HIFU) led to eradication of all clinically significant cancer in the treated lobe for 94% of patients with early prostate cancer, according to findings presented at the 2016 American Urological Association meeting.

HIFU resulted in complete ablation of all cancer in the treated lobe for 87 of 101 cases (86%) and absence of any cancer in the whole prostate (including untreated areas) in 68 cases (67%). After 2 years of follow-up, 89% of the patients remained alive without radical therapy (95% CI, 81.0-93.8). Almost 100% of patients had resolution of urinary incontinence at 12 months, and almost 80% of the men had preserved erectile function.

“HIFU hemiablation achieved excellent local control. HIFU was associated with a low morbidity profile and an acceptable rate of complications. We confirmed preservation of quality of life,” said lead investigator Pascal Rischmann, MD, PhD, chair of urology at Rangueil University Hospital in Toulouse, France. “HIFU hemiablation for localized prostate cancer provides a reliable alternative to whole-gland radical treatment for selected patients with intermediate-risk cancer.”

The findings came from multicenter trial aimed at demonstrating an intermediate role for HIFU in low- and intermediate-risk prostate cancer. Radical therapies have questionable benefits for that subgroup of patients and carry the risk of potential functional consequences, said Rischmann. Additionally, in this setting, active surveillance does not completely address the men’s needs, since there is a risk of understaging, undergrading, psychological stress, and delayed treatment.

“Partial treatment of the gland may fill the gap between active surveillance and radical treatments,” said Rischmann. “Hemigland ablation limits the risks of morbidity and may be amenable to the approximately 20% of patients who have unilateral disease.”

Investigators at 10 French centers enrolled patients older than 50 years with stage T1C or T2 disease, PSA level <15 ng/mL, unilateral tumor, Gleason grade &le;7, a maximum of two consecutive sextants involved, and &ge;5 mm distance from the tumor apex to the urethra by multiparametric MRI. Follow-up PSA measurements occurred at 3, 6, 12, and 24 months, MRI-guided biopsy at 6 to 12 months, and functional-quality of life assessments at 3, 6, and 12 months.

The primary endpoint was absence of clinically significant cancer in the treated side, defined as Gleason score >6, more than two positive biopsy cores, or cancer-core length >3 mm, regardless of grade. Secondary endpoints included absence of any cancer on biopsy, biochemical response, functional results, and quality of life.

Investigators enrolled 111 patients who had a mean age of 64.8 (&plusmn;6.2), mean PSA value of 6.2 ng/mL (&plusmn;2.6), and mean prostate volume of 31.6 cc (&plusmn; 12.3). Three fourths of the patients (74%) had tumors that were Gleason grade &le;6. The volume of the treated area of the prostate averaged 16.1 cc (&plusmn;5.1).

No patients were lost to follow-up, but two patients died of causes unrelated to the prostate cancer. Overall, 101 patients had follow-up biopsies and were available for the efficacy analysis, Rischmann.

During 2 years of follow-up, eight patients had repeat HIFU treatments, six had radical prostatectomy, three had external beam radiotherapy, and 16 patients enrolled in active surveillance. Three patients had second-line treatment: One underwent radical prostatectomy and two had radiation treatment. None of the additional treatments was associated with complications.