In the study, 42 men underwent focal ablation with high-intensity focused ultrasound (HIFU). Investigators used multiparametric magnetic resonance imaging (MRI) to identify cancerous areas. Almost 90% of men reported having erections satisfactory for intercourse at 12 months post-treatment. All 40 men who were pad-free at baseline were pad-free by three months and maintained pad-free continence at 12 months, according to an online report in The Lancet.
In addition, investigators found no biopsy evidence of cancer in the treated regions in 30 of 39 men who were biopsied at six months; 36 of the 39 were free of clinically significant cancer.
Of 31 men with good baseline function, 26 (84%) “achieved the trifecta status” of having leak-free and pad-free continence, erections sufficient for intercourse, and no evidence of clinically significant disease on multiparametric magnetic resonance imaging at 12 months.
“Focal therapy of discrete areas of cancer, whether unifocal or multifocal, is feasible, safe, and can be delivered in an ambulatory setting,” the researchers, led by Hashim U. Ahmed, MD, of University College London, noted.
With HIFU, tissue destruction occurs as a result of thermal, mechanical, and cavitation effects to produce a clearly demarcated region of coagulative necrosis surrounded by normal tissue on microscopic examination, the authors explained.
The researchers standardized the focal therapy process by setting three broad guidelines: a maximum of 60% of the prostate could be ablated; the edge of the ablation zone had to be at least 10 mm from a neurovascular bundle (the ablation zone had to be at least 5 mm from both neurovascular bundles if disease was bilateral); and untreated areas could not have any histologic evidence of cancer. High-grade prostate intraepithelial neoplasia and atypical small acinar proliferation were permitted.
“Focal therapy could hold promise in mitigating the harms that result from current therapeutic strategies,” the authors wrote.
In an accompanying editorial, Matvey Tsivian, MD, Michael R. Abern, MD, and Thomas J. Polascik, MD, of Duke University Medical Center in Durham, N.C., noted that the new study “represents the first rigorously designed study of the early outcomes of focal therapy.”
Focal therapy, they added, needs standardization, definition of consensual treatment schemes and nomenclature, as well as optimization of patient selection criteria. “With these issues addressed,” they wrote, “focal therapy could potentially become a mainstream therapy for localized prostate cancer that would offer personalized treatment tailored to the patient and his disease characteristics as opposed to conventional, stereotypes, whole-gland treatment.”