'Focal Therapy' Means More Precise Prostate Cancer Treatment

Prostate cancer treatments once ranged from wait-and-see (or active surveillance) for low-risk cases to invasive radiation or surgery, which often came with side effects, for severe cases.

In 2007, a middle-ground approach to treatment, known as focal therapy, became available and has continued to grow in implementation and effectiveness since. Most common in people ages 65 and older, and in Black men, prostate cancer affects about 1 in 8 men during their lifetime, according to the American Cancer Society.

Let's break down the ins and outs of focal therapies, including the benefits, potential side effects and who this treatment can help.

What is focal therapy?

Calling focal therapy a "type" of prostate cancer treatment isn't accurate because it's more of an umbrella term than a specific treatment. This less invasive approach can encompass therapies including high-intensity focused ultrasound (HIFU), cryotherapy and others.

"Focal therapy is a minimally invasive approach that precisely targets and destroys only the cancerous tumor in the prostate, which in some cases, can be as small as a grain of rice," said Mehran Movassaghi, M.D., a urologist with Providence St. John's Health Center in Santa Monica, California. He further explained that similar to a lumpectomy for breast cancer, it's not necessary for urologists to remove the entire prostate to ensure the cancer is gone.

Focal therapy comes in many varieties. Movassaghi specifically mentioned HIFU, irreversible electroporation, cryotherapy, photodynamic therapy, focal laser ablation or laser interstitial thermotherapy, radiofrequency ablation and focal brachytherapy. Here, the focus will be on HIFU, laser ablation and cryotherapy, three of the more common treatments.

How does focal therapy work?

"Focal therapy is a treatment for localized prostate cancer," said George R. Schade, M.D., a urology specialist with the University of Washington Health's Seattle Cancer Care Alliance. "[It's] less invasive than other treatments, meaning it does less harm to healthy tissue."

One benefit of focal therapy is it's an effective treatment whether there is one tumor or several.

"In men with a single tumor, it targets that tumor, while in men with multiple tumors, focal therapy may be used to treat the most aggressive 'index' tumor," Schade explained. "Though many prostate cancer cases have more than one tumor site, research indicates that the index lesion is what drives and predicts how any cancer will progress. If focal therapy can control the growth of the index lesion, the concept is that the cancer can be managed safely and effectively while minimizing side effects."

What exactly are the three common types of focal therapy and what do they entail?

HIFU

High-intensity focused ultrasound is an outpatient procedure that destroys cancer cells with ultrasound, or sound waves.

"[With the patient] under anesthesia, an ultrasound probe is inserted into the rectum and the sound waves heat up and destroy the targeted tissue, killing just the cancer cells while causing no effect on the tissue surrounding the treatment site," Schade explained, adding that no incision is required because the probe goes into the rectum.

Cryotherapy

Cryotherapy freezes cancer tissue by sending gas into the prostate with metal probes inserted under the skin.

"Typically, we will consider cryotherapy in someone who's had radiation therapy already but they had a recurrence after radiation therapy that's localized," said Brian McNeil, M.D., the chief of urology at University Hospital of Brooklyn in New York.

He added that cryotherapy is not considered a first-line treatment.

MRI fusion

HIFU or laser ablation, which uses precise laser radiation energy to burn away cancer cells, is often paired with magnetic resonance imaging (MRI). This allows the urologist a close, real-time view so they can be extremely specific in targeting tumors.

Advantages of focal therapies

The biggest advantage of focal therapies is they don't cause the same potential side effects, such as bowel symptoms, urinary incontinence and penile shrinkage, as more invasive treatments.

"If you remove someone's prostate, there are complications that happen after surgery, whether it's temporary incontinence, leakage of urine or erectile dysfunction," McNeil said, adding that some men who have their prostate removed lose the ability to ejaculate, which is an issue for men who want to have kids.

Unlike the wait-and-see technique, focal therapies target cancer and feel proactive. Plus, the procedures are performed on an outpatient basis and don't require a disruption of life.

Potential side effects of focal therapies

The good news concerning the side effects involved with focal therapy is that they usually subside on their own, and quickly.

In the short term, Schade said frequent urination, a burning sensation during urination and difficulty urinating are potential side effects immediately after HIFU.

"Additionally, HIFU has a small risk of urinary leakage and can cause retrograde ejaculation and decreased erections," he said.

Retrograde ejaculation occurs when semen collects in the bladder instead of coming out of the penis, though climax still occurs.

Unlike with surgery, over time there is the risk that a new tumor can develop in the untreated portion of the prostate, and it is possible to undertreat the site of focal therapy.

"Such undertreatment can carry a risk of disease progression, and thus, careful follow-up for men undergoing these treatments is critical," said James S. Wysock, M.D., a urologic oncologist at NYU Langone Health in New York City. "One aspect of focal therapy, however, is that if new disease is detected on surveillance, multiple options for treatment remain available, including repeating focal therapy."

The right candidates for focal therapy

A Gleason score or grade is a rating system used specifically for prostate cancer; it indicates how quickly cancer may spread. It's measured on a scale of 1 to 10, with 1 meaning the tumor looks like normal prostate cells.

"Men with Gleason scores of 7 or less and who have early-stage [localized] cancer that has not spread beyond the walls of the prostate are typically good candidates," Movassaghi explained. "Most doctors will also take into account the patient's health, size and location of the tumor, and risk of spreading. An MRI, ultrasound and/or biopsy are the modalities for diagnosing the grade and state of prostate cancer."