Focal Therapy for Prostate Cancer

Some men with early stage (localized) prostate cancer who previously had to choose between active surveillance and aggressive treatment with a greater risk for side effects, now have a new option for treatment, focal therapy.

Prostate cancer experts describe focal therapy as being similar in concept to a lumpectomy for breast cancer. Rather than removing the entire prostate, focal therapy is a less invasive way to destroy just the cancer while leaving healthy tissue in place.

Focal therapy is an overall term that refers to several minimally invasive treatments that target only the parts of the prostate gland where cancer is located. The goal of the treatment is to ablate, or destroy, small tumors within the prostate while leaving the remainder of the gland intact.

Focal therapy is based on the concept that, although prostate cancer can present as multifocal disease within the prostate gland, some patients may have a significant single index intraprostatic lesion. This index lesion may be associated with the most aggressive nidus of cancer within the gland and may be the most appropriate target for treatment. A prerequisite for focal therapy involves advanced mapping of lesions within the prostate. This can be done with a saturation biopsy or, more commonly, with MRI imaging with focused biopsy or a 3-dimensional transperineal mapping biopsy to identify appropriate patients with clinically significant disease, to provide an appropriate index target, and to provide an appropriate target for follow-up scanning and biopsies.

Potential Benefits of Focal Therapy for Early-Stage Prostate Cancer

• Lower risk for side effects such as urinary incontinence, impotence and decreased bowel function, as compared to surgery or radiation therapy.
• Minimally invasive, outpatient procedure.
• If necessary, focal therapies can be repeated in the future.
• Unlike some prostate cancer treatments, focal therapies do not limit the option to have radiation therapy or surgical treatment at a later time.
• Quick recovery, it is an outpatient procedure and patients can return to work the following day.

Patient Selection for Focal Therapy

When focal therapy for prostate cancer first began to be used in about 2007, it was only as an alternative to active surveillance in very low-risk patients. Since then, the use of focal therapy has expanded to include some intermediate and even high-risk patients.

Although there are no set rules about determining the best candidates for focal therapy, patients with overall low or intermediate-risk disease, and who have biopsy-proven cancer localized to a single area of the prostate, are usually the best choices for this type of treatment.
In each case, the treating physician will consider the patient’s general health and psychological outlook, the size and location of the tumor, and their chances of disease progression. Use of tests such as MRI, transrectal ultrasound, and biopsy (tissue samples examined by a pathologist) can help decide if a patient will benefit more from focal therapy or from conventional treatments.

Types of Focal Therapy

Focal therapy uses ablation, which is the use of extreme temperatures to destroy tumors. In focal ablation, the area of the prostate that contains the most serious cancer is targeted, rather than treating the entire prostate gland. Focal ablation techniques include:

Cryotherapy — Use of very cold gases passed through needles to freeze and destroy cancer tissue.

High intensity focused ultrasound (HIFU) —The use of high-frequency sound waves directed at the tumor through an ultrasound probe inserted into the rectum. The high intensity waves heat and destroy the diseased tissue.

Photodynamic therapy — A drug called a photosensitizer is injected into the bloodstream. This drug then absorbs light rays directed at the tumor and produces an active form of oxygen that destroys cancer cells.

Laser ablation — The use of laser radiation energy pinpointed to a very small area to burn away cancerous tissue. Laser ablation has the advantage of being able to be performed at the same time as magnetic resonance imaging (MRI), allowing very specific targeting and also real-time views of results.

What can be Expected after Treatment with Focal Therapy

Focal therapy is a relatively new concept, but initial evidence supports that most men receiving the treatment remain potent and only a very small percentage become incontinent (lose the ability to control their urine flow). Impotence and incontinence are considered the two most common complications associated with any prostate cancer treatment.

It is important that patients understand that focal therapy may only be a temporary solution. Because focal therapy focuses on a specific area of the prostate, at least half of the gland will go untreated. This may mean that small, developing tumors are not destroyed.
All patients undergoing focal therapy should have very regular follow-up care to carefully monitor any changes. If a tumor is found in the future, the patient will need to undergo additional treatment.

Focal therapy does not exclude any treatment options for the future – including a repeat focal therapy or conventional therapy. The patient will likely enjoy an uninterrupted quality of life from the first treatment to possible further treatment if required. Recovery from focal therapy, including the time needed to keep a urinary drainage catheter in place after the procedure, is a matter of just a few days.