Focal therapy for localized unifocal and multifocal prostate cancer: a prospective development study using real time MR guided focused ultrasound

To assess safety and feasibility of non-invasive high intensity 3T MR guided focused ultrasound (MRgFUS) treatment of localized prostate cancer in an exploratory designed study. Men aged 45-80 years were eligible for this prospective study if they had low-risk localized prostate cancer (prostate specific antigen [PSA] ≤10 ng/mL, Gleason score ≤ 3 + 3), with no previous androgen deprivation or treatment for prostate cancer, and who could safely undergo multiparametric MRI (Discovery 750, GE; Gd-Bopta, Bracco) and have a spinal anesthetic. Patients underwent focal therapy using real time MR guided high intensity focused ultrasound (MRgFUS), delivered to all known cancer lesions, with a margin of normal tissue. Primary endpoints were adverse events (serious and otherwise) and urinary symptoms and erectile function assessed using patient questionnaires. 8 men were recruited between June 2011 and June 2012. After treatment, one man was admitted to hospital for acute urinary retention. Another patient had self-resolving, mild, intermittent dysuria (median duration 5.0 days). Urinary tract infection was not reported. Urinary debris occurred in 6 men (75%), with a median duration of 12 days. Median overall International Index of Erectile Function-15 (IIEF-15) scores were similar at baseline and at 6 to 12 months (p=0.060), as were median IIEF-15 scores for intercourse satisfaction (p=0.433), sexual desire (p=0.622), and overall satisfaction (p=0.256). There was an improvement in lower urinary tract symptoms, assessed by International Prostate Symptom Score (IPSS), between baseline and 6 to 12 months (p=0.026). All 8 men with no baseline urinary incontinence were leak-free and pad-free by 9 months. No histological evidence of cancer was identified in 7 of 8 men biopsied at 6 months (87,5%); overall, the entire population (8 patients) was free of clinically significant cancer and had no evidence of disease on multi-parametric MRI at 6 to 12 months. MR guided Focused Ultrasound focal therapy of individual prostate cancer lesions, whether multifocal or unifocal, leads to a low rate of genitourinary side-effects and an encouraging rate of early absence of clinically significant prostate cancer.