Brian J. Miles, MD
For more than a generation, the notion of lumpectomy instead of radical mastectomy for breast cancer was met with scorn and treated as heresy. Now, it is the standard of care and has saved the physical QoL for many women. Prostate cancer (PCa), which is similar to breast cancer in many ways, has also been considered not amenable to focal therapy as a form of lumpectomy. This is because of the size of the prostate, its relative inaccessibility, the fact that PCa is often multifocal, and concerns that focal therapy may rule out some treatment options if the cancer recurs. However, with the recent FDA clearance of high-intensity focused ultrasound (HIFU) in prostate disease, this therapeutic option has become viable. HIFU has been used for decades in Europe with excellent oncologic control and acceptable AEs.
The potential for prostate lumpectomies expanded notably in June 2018, which is when the FDA cleared the Focal One HIFU device as the first medical apparatus designed specifically for focal treatment of the prostate, although earlier devices made this procedure possible. As with all technological advances, long-term studies and clinical data will ultimately determine whether Focal One distinguishes itself as a uniquely useful instrument. Nevertheless, its arrival is significant due to the degree of precision with which diseased prostate tissue can be ablated while sparing healthy tissue and thus reducing AEs.
The Focal One device provides precision capability to treat the prostate by integrating magnetic resonance and 3D biopsy data with real-time ultrasound imaging—a process known as fusion. This melding of advanced imagery and patient diagnostic data provides a detailed 3D view of the prostate on a large monitor in real time, enabling direct highintensity ultrasound waves to ablate the targeted area within the prostate.
Because this fusion of technologies allows for improved targeting of diseased tissue during treatment planning, the margins around the contours of that tissue can be drawn more concisely than the margin contours required by less-precise procedures used in the past, thus eliminating the need to remove larger volumes of prostate tissue. In addition, this advancement in focal ultrasound prostate tissue ablation enables clinicians to enact a protocol that respects the maxim “right patient, right treatment, right time,” because the focal HIFU therapy can be customized for each patient and for each clinical scenario.
During the procedure the device’s proximity to the rectal wall is constantly monitored for patient safety. The robotic HIFU device automatically readjusts itself and, if necessary, stops transmission of the high-frequency waves anytime they are too close to the rectal wall. This aids in avoiding rectal injury.
Figure 1. German Study: Survival Rates for Patients With Localized PCa Treated With HIFU1
Future long-term studies are hoped to provide data needed to fully analyze the potential of focal HIFU therapy as an alternative to radiation and radical prostatectomy for treatment of localized PCa in the United States. European researchers have published positive peer-reviewed studies of the use of this technology for whole gland ablation.
Here is a brief review of 2 such studies: In 2013, the Journal of Urology
published a German study of 704 patients treated with HIFU, in which co-investigators Stefan Thüroff and Christian Chaussy concluded that long-term follow-up with HIFU therapy demonstrated a high overall rate of cancerspecific survival (99%) and 10-year salvage treatment-free rates of 98% in low-risk, 72% in intermediate-risk, and 68% in high-risk patients. “Advances in HIFU technology and clinical practice, as well as the use of neoadjuvant transurethral prostate resection, allow the complete treatment of any size prostate without inducing metastasis,” the authors wrote.1
The study assessed patients with primary localized PCa (T1-2, N0, M0, and prostate specific antigen [PSA] at first diagnosis <50 ng/mL) and follow-up longer than 15 months. Patients with previous long-term androgen deprivation therapy (ADT), locally advanced PCa, or any therapy influencing PSA were excluded from the study.