It is important to keep in mind that the overarching issue is with the patient population and the study design, and not the focused ultrasound technology. Pragmatically, the burden is very high for a clinical trial to demonstrate an improvement in outcome in patients with low risk prostate cancer, whether the treatment is focused ultrasound, cryotherapy, radiotherapy, etc. As noted by a panel member, thousands of men would have to be followed for 30 years to prove efficacy. In addition, EDAP had significant difficulty recruiting for the cryotherapy control arm, having to change their study plans after five years of trying to enroll patients.
The problem confronting the urological community is that there are a substantial number of patients who are not comfortable with the watchful waiting paradigm after they are diagnosed with low-grade prostate cancer. An increasing number of these patients who have the financial wherewithal are seeking treatment outside of the United States. The vexing issue is how to reconcile the disconnect between the desire of patients to be treated with a lack of availability of the technology in the US due to regulatory hurdles.
Similarly, women with low-risk breast cancer frequently opt to have it treated aggressively, despite the benefits still being actively debated in the medical community. The difference is that these women are able to determine their own benefit risk equation and have options available to them. At the Panel meeting, the Foundation encouraged the FDA to take patients’ voices into consideration around risk benefit, particularly with a noninvasive approach like focused ultrasound.
What this dilemma highlights is the tremendous need to have a diagnostic that can differentiate those patients with low grade prostate cancer that need treatment to avoid disease progression versus those with more indolent tumors that do not require definitive treatment.
This fall, an FDA panel will review Sonacare’s Sonabalate device for recurrent prostate cancer. We hope that their data on more advanced patients will be compelling to the panel.
Neal F. Kassell, MD