High-intensity focused ultrasound in prostate cancer: Today's outcomes and tomorrow's perspectives

Abstract

High-intensity focused ultrasound (HIFU) is a minimally invasive therapy applied for prostate cancer that capitalizes on the coagulation necrosis that occurs at temperatures greater than 60°C. Owing to a lack of long-term follow-up data the procedure is still considered experimental treatment. As primary therapy, HIFU is indicated in patients aged ≥70 years with clinical organ-confined disease, although it has also been used, with encouraging results, as first line salvage therapy after definitive treatment, and in locally advanced (T3-4) and non-metastatic hormone-resistant prostate cancer. Morbidity associated with this treatment method appears to be low and includes urinary retention (1-9%), urethral stricture (4-14%), incontinence (1-15%), erectile dysfunction (13-53%) and rectourethral fistulae (0-3%). The risk of complications increases with repeated treatments. A few studies have recently been published on HIFU as focal therapy. HIFU technology can be enhanced using means such as ultrasound microbubble contrast agents for assessment of therapy efficacy, magnetic resonance imaging to guide the enhancement of heat rate, and localized drug and gene delivery.

Urologic cancer in Taiwan

“…The complications of cryotherapy are common but modest, mainly lower urinary tract obstruction and erectile dysfunction. The complication of HIFU included urine retention, need for subsequent TURP and urethral stricture (19). This technology still needs more research and long-term data to show its clinical efficacy and therapeutic role.…”

Multimodal imaging in focal therapy planning and assessment in primary prostate cancer

“…Others have reported similar data [42]. Palermo et al reported the following adverse events, urinary retention in 1-9%, urethral structure in 4-14%, urinary incontinence in 1-15%, erectile dysfunction in 13-53% and rectourethral fistulae in 0-3% of patients [43]. A multicenter prospective investigation has also been designed as a medium-term (36 months) follow-up trial (The INDEX study) for assessment of biopsy outcomes to focal HIFU therapy in men with low-intermediate prostate cancer (PSA<15 ng/ml, Gleason <7, T2cN0M0)[44].…”

Ultrasound for Drug/Gene Delivery

“…Nanoparticle delivery has been shown to augment gene expression in a sitespecific manner in preclinical studies for a variety of tumors, including brain cancer [86], prostate cancer [87], hepatocellular carcinoma [88], pancreatic cancer [89], and kidney cancer [90]. Viral vectors are efficient but have undesired biolocalization problems.…”