Urology Times® is celebrating its 50th anniversary in 2022. To mark the occasion, we are high-lighting 50 of the top innovations and developments that have transformed the field of urology over the past 50 years. In this installment, Jennifer A. Linehan, MD, discusses high-intensity focused ultrasound (HIFU) for the treatment of prostate cancer. Linehan is an associate professor of urology and urologic oncology at the Saint John’s Cancer Institute in Santa Monica, California.

Please provide an overview of the development of high-intensity focused ultrasound (HIFU) for treatment of prostate cancer.

We know that prostate cancer breaks into 4 main groups: very low grade, low grade, intermediate ,and high grade. We found that many low-grade prostate cancers did not need to be treated and patients could go on active surveillance and didn’t affect overall survival or affect quality of life. We started to look for ways to treat the cancer that were less invasive, but at the same time allow the patient to maintain as much of their quality of life as possible, as well as their continence and erectile function.

Focal therapies became the middle ground between active surveillance and more radical therapy like surgery or radiation. HIFU is able to ablate and treat the cancer without damaging the surrounding structures, and you can also do this through the rectum in a very effective manner without making any incisions on patients. You can do this in 1 treatment and retreat if needed. It also does not burn bridges if the patient needs radiation or surgery later. Multiple studies have shown its effectiveness over the past 10 years.

It became more and more of a clear option to use the technology to further the treatment of prostate cancer and provide options to patients who didn’t want or could not have surgery or radiation.

Were there other focal therapies available at the time that you looked at HIFU?

Yes. Technically, there are 8 different energy sources you can use for focal therapy: HIFU, irreversible electroporation , cryotherapy, photodynamic therapy , focal laser ablation or laser interstitial thermotherapy, radiofrequency ablation, and focal brachytherapy.

Focal therapy with HIFU was attractive because, no. 1, there were fewer side effects for patients and the technology to use the energy modality was the most advanced and “surgeon friendly.” That’s why it is such an attractive option for surgeons and for patients.

What are some of the other innovative treatments that have become popular in recent years?

There are other focal options that we’ve have explored for prostate cancer, like cryotherapy or brachytherapy, but a lot of the targeting is done through cognitive fusion, which can be difficult at times. You can treat the tumor inside the MRI, using MRI to target the lesion and delivering radiofrequency ablation or cryotherapy was another method but it often required the patient to actually be inside the MRI machine, which could take up to 4 hours.

The Tulsa procedure, like HIFU, uses ultrasound energy. The probe goes into the urethra and requires a cooling method for the urethra. We know that most cancers are in the peripheral prostate, so for me, it always made sense to treat transrectal. Focal One and HIFU have made it really easy to target and treat the lesion. I think for some patients, rectal access to the prostate cancer causes fewer symptoms like burning and dysuria.

What new innovations are on the horizon for treatment of prostate cancer?

The true innovation is finding better ways to do focal therapy that decreases the side effects for the patients and still treats the lesion effectively. I think that although active surveillance has been a great option for many patients, it does fail in some patients and many patients have anxiety with it. Some men don’t like the idea of just waiting and not doing anything about the cancer. So that’s where focal therapy comes in.

With the Focal One, we have that ability to do the fusion of the MRI images and the ultrasound for guidance to the lesion. You know you’re treating the specific area and the patient’s going to get better results when you target in real time. To be very frank, I think the energy source is less important than the technology you use to deliver the energy source. That is the real innovation.

What would you say is HIFU’s legacy in the history of prostate cancer treatment and management?

HIFU’s legacy is that you’re able to treat prostate cancer with minimal side effects to the patient in a way where you’re able to distinctly target the lesion and not treat any other tissue that you don’t want to treat or nerves or arteries or anything that’s in the vicinity of the prostate that’s going to affect the patient’s overall urinary function or their erectile function. Urologists and doctors always worry about any transrectal therapies, and the small risk of creating fistula tracks or other issues in the rectal wall. The biggest benefit of HIFU is that the technology allows you to actually see where the rectal wall is and you can divert the energy so that it’s not going to affect the rectal wall or surrounding tissues. HIFU has always been special in that it treats where you want and not where you don’t. I always recall talking to my surgical oncology friend, who uses it for liver cancer because you can literally treat tissue that is next to the vena cava or portal vein without injury.