Expert Discusses Optimizing HIFU and Other Strategies in Prostate Cancer

Timothy J. Daskivich, MD

Although High-intensity focused ultrasound (HIFU) is only approved in the United States for prostate tissue ablation, it has demonstrated efficacy as a treatment for patients with prostate cancer, says Timothy J. Daskivich, MD.

Daskivich noted, however, that HIFU must be used in the proper setting to avoid overtreatment. “We need to be careful with who we treat with upfront focal therapy. We shouldn't overuse HIFU for very low-risk tumors, or the majority of low-risk tumors because they should be managed with active surveillance,” said Daskivich.

“Select intermediate-risk tumors are the ones we can capture with HIFU; that’s the best use of the technology. As far as imaging goes, multiparametric MRI is going to become the standard of care for patients on active surveillance. It may even become the standard of care for identifying disease in patients with elevated prostate-specific antigen,” Daskivich added.

OncLive: When will we see the widespread adoption of HIFU?

What are other imaging modalities that are used?

In an interview during the 2018 OncLive^® State of the Science Summit™ on Genitourinary Cancers, Daskivich, an assistant professor of surgery at Cedars-Sinai Medical Center, discussed optimizing the use of HIFU and other treatment strategies in the prostate cancer armamentarium.Daskivich: HIFU has been FDA approved since October 2015 for the treatment of prostate tissue. It’s now used by many academic centers across the United States for treatment of patients with prostate cancer. It's been used in Canada, Mexico, and Europe for the last 20 years to treat prostate cancer, so there's a track record elsewhere. We’re going to see more use of focal therapy as experience in the United States evolves.Multiparametric MRI is an excellent modality for identifying high-grade tumors. It has a 20% miss rate. The beauty of it is that it ignores low-grade tumors. Low-grade tumors, such as Gleason 6 tumors, are ones we now watch and don't treat aggressively. Often, we don't want to find them in older men because that can lead to harmful overtreatment. Cedars-Sinai Medical Center has developed a platform for high-resolution MRI that improves resolution over multiparametric MRI by about six-fold. It identifies 60% of tumors that are invisible to multiparametric MRI.

How can rates of active surveillance be improved to avoid overtreatment?

PET-MRI is another modality, but it is only available at a handful of centers across the United States; Cedars-Sinai Medical Center is one of them. Ongoing clinical trials are investigating the use of PET tracers like fluciclovine to identify tumors within the prostate gland.It has to be driven by patient education and physician uptake. In the academic community, everyone believes active surveillance is the way to go for very low-risk prostate cancer and the majority of low-risk prostate cancers. I always tell patients, “The best treatment is no treatment.” That’s how I start every conversation about prostate cancer.

Do you prefer adjuvant or early-salvage radiation therapy for patients?

If you were to predict the treatment landscape 1 year from now, what would it look like?

Will surgery ever become obsolete?

High-grade cancers should be treated aggressively and carefully. The majority of patients in the United States who are diagnosed with low-grade cancers need to be monitored with active surveillance as the primary, preferred strategy in order to maximize quality of life and minimize morbidity.There's no data that suggest that one is better than the other; however, adjuvant radiation therapy is one of the few treatments in urologic care that we have great evidence for. A study showed that it decreases the rate of biochemical recurrence, the rate of local recurrence, and may improve survival. The other study was unpowered to prove it. I would lean toward adjuvant radiation therapy. That's my personal preference, but many physicians do early-salvage therapy. Future studies are going to tell us which one is better. My hope is that active surveillance will be the primary therapy for very low-risk and the majority of low-risk prostate cancers. For select low-risk prostate cancers, HIFU, or other minimally invasive, minimally morbid treatments will be used for those patients who need treatment. For favorable-risk, low-volume, localized, intermediate-risk tumors, HIFU will become the standard of care. For unfavorable, intermediate-risk and above tumors, the evidence suggests that, right now, surgery and radiation are the appropriate therapies; time will tell. As a surgeon, it's hard to know and it's hard to say that you're looking forward to that day. As an advocate for patient welfare, surgery will become less morbid through improvements in techniques and approaches. HIFU represents a change in the care of prostate cancer. It has been shown to improve outcomes. It's a completely different paradigm of focal treatment as opposed to whole-gland treatment. As time goes on and technology improves, we can develop more therapies like this that are still surgical in nature but minimize side effects and maximize cancer control.