Focal laser ablation safe for low-risk prostate Ca

Focal laser ablation is safe and can be performed without the troubling complications associated with more aggressive therapies for low-risk prostate cancer, results of a small phase I study indicate.

None of the nine men treated in the study had a significant side effect. Six months after therapy, seven of the nine patients (78%) no longer had evidence of cancerous tissue in biopsies of the treated area.

"This experimental approach appears to combine the most attractive element of treatment, eradication of the cancer, with the most appealing element of active surveillance, maintaining quality of life," said first author Aytekin Oto, MD, of the University of Chicago Medicine, who worked on the study with Scott Eggener, MD, and colleagues. "These early safety results are promising, but we definitely need longer-term data."

For the study, which was published online in Radiology (Feb. 25, 2013), the authors enrolled nine men with biopsy-confirmed, low-risk prostate cancers (Gleason score 6 or 7, less than 12 mm of cancer) with magnetic resonance imaging of the prostate showing a small area of cancer. Patients were treated under conscious sedation while lying in an MRI scanner. After injecting a local anesthetic, the physicians inserted a small catheter across the perineum and used it to guide a tiny optical fiber, the laser, and a cooling device into the prostate.

Under MRI guidance, the laser was positioned within the cancer and used to heat the area to a temperature that would kill cancer cells. The team checked the temperatures outside the treatment region every 5 seconds to protect healthy tissue, especially those near critical structures such as the urethra and rectal wall.

The entire procedure took less than 4 hours. That decreased to 2.5 hours as the team gained experience. The actual heat treatment averaged 4.3 minutes. All patients left the hospital the same day.

No patient had a major complication or a serious adverse effect. Average scores for urinary or sexual function were not significantly different 1, 3, or 6 months after treatment. No patient had symptoms of rectal wall damage.

Biopsies of the treated areas 6 months after the procedure found no evidence of prostate cancer in seven of the nine patients (78%). The other two patients had small (2.5 mm and 1 mm) remaining cancers.

These are preliminary results, the authors caution, following a small number of patients for a short time. It will take much longer follow-up, the authors say, to fully evaluate this approach.

A phase II trial of this procedure, sponsored by the National Institutes of Health, is now under way at the University of Chicago Medicine. The physicians hope to enroll 27 patients.

The University of Chicago Medicine has received grants from Visualase and Philips Healthcare.