Science, risks and data behind focal therapy for prostate cancer

When dealing with most localized solid tumors, surgeons often aim to preserve as much of the affected organ as feasible, removing only the cancerous area along with a margin of healthy tissue to prevent further spread. However, in prostate cancer cases, treatment usually involves either complete removal or irradiation of the entire gland, unless the disease is low-grade and unlikely to become life-threatening. Such approaches can lead to significant long-term side effects, including urinary incontinence and erectile dysfunction. 

A less aggressive treatment approach, known as focal therapy, has been garnering interest among patients and physicians for several years, despite being considered experimental in treatment guidelines. Focal therapy specifically targets lesions detectable on MRI scans and employs various technologies to destroy cancer cells through heating, freezing, burning, or even electrocution. These treatments are usually completed in a single session and can sometimes be administered in a doctor’s office, which enhances their attractiveness. 

Although focal therapy technologies have existed since the late 1990s, interest has surged in recent years as MRI technology has improved, allowing for more precise identification of cancerous lesions. This topic was prominently discussed at the recent annual urology conference. 

Urologic oncologists are divided over the advantages of focal therapy compared to traditional surgery or radiation. Those who offer focal therapy found support from a recent U.K. study that reported that 10 years post-treatment, only 0.1% of patients who underwent focal therapy had died from prostate cancer, a survival rate comparable to standard treatments. Patients reported higher satisfaction and experienced fewer side effects. However, many specialists are calling for more long-term data and randomized trials to compare focal therapies directly against standard treatments. 

The American Urological Association still labels focal therapy as experimental. While acknowledging it as an option for intermediate-risk cancer, the association advises that it should only be used within studies and registries. A recent paper noted that half of the patients receiving focal therapy had either higher-risk or lower-risk cancers, including those that guidelines suggest should be monitored through active surveillance.

Nonetheless, many prominent cancer centers and independent practitioners offer focal therapy, with patients expressing high levels of satisfaction, despite the lack of commercial insurance coverage. 

“I’m super happy with it. I have zero side effects,” said Chris Brosseau, a 48-year-old from Denver with a family history of aggressive prostate cancer. He opted for focal therapy, spending about $17,000 out of pocket, as many commercial insurers do not cover it, although Medicare does. “I realize it can come back because I didn’t treat my whole prostate,” he said. “If it comes back on the other side, I wouldn’t hesitate to do this again.” 

What is focal therapy?

Focal therapy involves a range of FDA-approved technologies designed to eradicate cancerous tissue. The most widely used methods include cryotherapy, laser ablation, and high-intensity focused ultrasound (HIFU), each with a long history. The choice of method typically depends on the characteristics of the lesion. Notably, localized radiation is not considered part of focal therapy.

Cryotherapy, which uses extreme cold delivered via a probe, was once the most popular, accounting for nearly 80% of procedures in 2010; by 2023, its use had dropped to 20%. Laser ablation accounted for about 45% of treatments, while HIFU, which employs high-frequency sound waves to destroy cells with heat, became the fastest-growing method, making up 35% of procedures in 2023. 

According to AUA guidelines, focal therapy is suitable for about 10% to 20% of prostate cancer cases within studies, particularly for patients with intermediate-risk cancer—whether favorable or unfavorable. Despite this, uptake remains low, with recent data indicating that only 1.3% of prostate cancer patients in the U.S. received focal therapy.

Providers who advocate for focal therapy highlight its advantages over other treatments. Prostatectomy, the surgical removal of the prostate, involves a longer recovery period and can cause initial incontinence in nearly all patients; while most regain bladder control within a year, 5% to 10% may suffer permanent incontinence. Additionally, more than half of the men undergoing surgery experience erectile dysfunction in the medium to long term. Radiation therapy, although associated with fewer long-term side effects, can still result in temporary incontinence and erectile dysfunction and typically requires several weeks of daily sessions. 

Conversely, focal therapy is generally a single-session treatment lasting between 40 minutes to a few hours. Some patients may need a catheter for a period afterward, though the side effects are usually minimal unless the lesion is near sensitive areas prone to erectile dysfunction. 

“There are times you go and treat someone with focal therapy and you know with a pretty darn high likelihood there’s going to be close to zero chance of side effects,” said Scott Eggener, a professor of urology at the University of California, Los Angeles. However, he cautioned that “there’s other areas of the prostate near the nerves or the sphincter where … there’s a real risk of side effects that [patients] might encounter.” 

Post-treatment, patients are monitored through blood tests, MRIs, and sometimes biopsies. If cancer reappears in other parts of the prostate, additional focal therapy sessions may be appropriate, but if it recurs in the treated area, radiation or surgery is usually recommended.

“In my experience of doing this, and I’ve been doing it for 10 years, greater than 95% of the patients when they’re eligible for focal choose focal therapy,” said Abhinav Sidana, a urologic oncologist and the director of focal therapy at the University of Chicago School of Medicine. Though he also performs prostatectomies, he understands the choice: “An average-skilled surgeon doing focal therapy will end up having better functional outcomes than sometimes even the most skilled prostatectomist,” he said. 

An experimental treatment

Consulting with providers who do not offer focal therapy reveals a contrasting perspective. Skeptics question the thoroughness of the data on its effectiveness in treating cancer, the occurrence of side effects, and the results of different technologies. 

“Focal therapy hasn’t been evaluated carefully and robustly,” said Tyler Seibert, an associate professor at the University of California, San Diego. He argues that it should be directly compared with established treatments to determine if it provides better outcomes or equivalent results with more favorable side effects. “The only way to know that is to do a head-to-head randomized trial, and that’s just what we’re missing with focal therapy,” he said. 

He acknowledges the significant challenges in conducting such trials, especially since “patients who are excited about focal therapy are sometimes reluctant to be randomized,” which he sees as a communication failure. “That means that we’ve messaged poorly, because why are the patients so sure that they want this thing that those of us looking at the data objectively are saying, ‘Well, we don’t know’?” Seibert said. 

Eggener, who has researched focal therapy, believes more data is essential, particularly because it remains unclear which method is most effective. “As far as which technology, there’s no direct comparisons, it’s all conjecture on which might be better than the other.” 

This lack of clarity is a concern even for some focal therapy providers, who lament that most registries lump all focal therapy methods together, making it difficult to determine which has superior outcomes or fewer side effects. “It’s focal therapy no matter how you did it,” said Samuel Peretsman, a urological oncologist and the chief medical officer of HIFU device-maker Sonablate. “We’re just going to call it all focal therapy so we can scale up the amount of data to analyze it. But the reality is all those tools do have varying outcomes, varying side effects, varying cure rates.” 

In response, Sonablate has initiated its own registry, though not all focal therapy providers see the need to differentiate between tools. “We should club all of them together,” said Sidana, emphasizing that the concept of ablation itself should be the focus of evaluation. 

Providers who support focal therapy dismiss the notion that more data is needed before it receives official approval. “When they say that focal therapy is experimental, I say: ‘Which bit?’” remarked Mark Emberton, a professor of Interventional oncology at University College London who has been using focal therapy for at least 20 years. 

“We have plenty of data for focal therapy,” Sidana stated, noting that many medical procedures rely on the clinical judgment of physicians. He pointed out that other technologies, such as robotic surgery or brachytherapy (where radioactive seeds are implanted in the prostate), were less studied when first introduced. The only real unknown with focal therapy, he said, is whether it impacts the potential lifespan of patients compared to prostatectomies or radiation therapy. 

U.K. data indicates that for patients monitored over 10 years, survival with “focal therapy is not inferior to radical surgery, however, it is much better in terms of quality of life,” Sidana said. “When patients look at that data, they’re like, ‘OK, 10 years is enough. I don’t care if 20-year outcomes of prostatectomy are going to be better than focal therapy.’” 

He acknowledged the possibility that focal therapy might not offer the same life expectancy, but argued it shouldn’t be the sole metric for evaluation. “A lot of these patients want to live in the present; they don’t want to lose their sexual function today so that they live one year longer at the age of 90 versus being sexually active for the next 10 years.” 

This perspective resonated with Brosseau. “I’m relatively young and I get that there might be another spot that comes up someday, and I’m OK with that,” he said. “The insurance would cover removal or radiation, and neither of those really appealed to me.”

The danger of overtreatment 

Critics of focal therapy also warn of the risk of unnecessary treatments. “The problem with focal therapy is many of the people who do well with focal therapy would have done well with observation,” said Otis Brawley, professor of oncology and epidemiology at Johns Hopkins University. 

Recent research published in JAMA highlighted that focal therapy is frequently used in cases that fall outside the urology association’s recommendations: 51% of treatments were performed on cancers classified as either higher or lower risk than intermediate. For patients with low-risk cancer, there was a 4% likelihood of receiving focal therapy when guidelines suggest active surveillance. 

“Some [patients] get surveillance fatigue. Some get surveillance anxiety. And you’re still being tested, you’re getting MRIs, you’re getting biopsies — there’s a burden of surveillance,” Peretsman said. Until recently, intervention involved risks and side effects, but focal therapy shifts the balance, he said. “[Patients] look at that balance a little differently, like ‘I can take care of this anxiety and be out the door in 40 minutes, have sex in three days and never use a pad’ — they are reassessing the risk-benefit [profile],” he said.

While some doctors are willing to treat patients to alleviate stress, others view it as overtreatment and a missed chance to demonstrate the value of active surveillance. “There are a host of patients who, emotionally and mentally, just can’t handle the fact they have cancer and we’re going to watch it,” Brawley said. “Now, for those people, I’m not … going to recommend that we give them a half-proven treatment so that we can allay their fears, and in my mind, focal therapy is a not fully proven treatment. It may be a good treatment, but it’s not fully proven.”

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