Focal therapy and imaging in prostate and kidney cancer: high-intensity focused ultrasound ablation of small renal tumors.

The rising incidence of small, incidentally detected renal masses in elderly, infirm patients has raised interest in minimally invasive, energy ablative techniques. High-intensity focused ultrasound (HIFU) delivers ultrasonic energy, resulting in heat and tissue destruction in the targeted tissue at a selected depth. In contrast to radiofrequency ablation and cryoablation, HIFU does not require puncturing the tumor, avoiding the high risk of hemorrhage or tumor spillage. While the extracorporeal approach shows unsatisfactory results, laparoscopic HIFU appears to be a promising alternative treatment option. Problems with respiratory movement and interphases, as seen in extracorporeal HIFU, are avoided when the transducer is brought directly to the target by laparoscopic HIFU. Potential benefits of laparoscopic HIFU are decreased morbidity, shorter hospitalization and convalescence, and preservation of renal function. Nevertheless, further prospective studies have to be performed to define the oncological success of HIFU as an alternative to open and laparoscopic surgery in small renal masses.