April 17, 2012 -- An experimental treatment zaps prostate tumors while leaving healthy prostate tissue intact.
The treatment, under development by Hashim Ahmed, MD, and colleagues at London's University College Hospital, uses high-intensity focused ultrasound (HIFU) to blast away small patches of cancer cells. This "focal therapy" is intended to reduce the serious side effects common with standard treatments for prostate cancer.
In standard therapy, the whole prostate is treated with radiation or removed surgically. Both types of treatment can lead to significant problems. These include:
- Urinary incontinence in 5% to 20% of patients.
- Erectile dysfunction in 30%-70% of patients.
- Bowel toxicity, including incontinence, diarrhea, and anal bleeding, in 5% to 10% of patients.
Ultrasonic Waves Blast Prostate Tumors
Ahmed and colleagues treated 41 men with focal ultrasound therapy. The men had early prostate cancer: no more than stage II cancer, PSA levels no higher than 15, and a Gleason tumor score no higher than 7.
MRI imaging identified small areas of cancer cells to be treated with ultrasonic waves, delivered by a probe to generate heat in the cells to be destroyed.
After 12 months, none of the men in the trial had urinary incontinence and almost nine out of 10 men (89%) could attain satisfactory erections.
The researchers also found that 95% of the men who underwent biopsies were cancer-free after a year, although four had needed retreatment with the focal therapy.
"Focal therapy of individual prostate cancer lesions ... leads to a low rate of [genital and urinary] side effects and an encouraging rate of early freedom from clinically significant prostate cancer," Ahmed and colleagues report in the journal Lancet Oncology.
Focal Ultrasound for Prostate Cancer: Further Studies Needed
The researchers note that their pilot study, while encouraging, does not yet prove that focal ultrasound therapy is ready for prime time. Larger studies are now needed to confirm their initial findings.
Commenting on the study, Owen Sharp, chief executive of the U.K.'s Prostate Cancer Charity, said, "We welcome the development of any prostate cancer treatment which limits the possibility of damaging side effects such as incontinence and impotence. These early results certainly indicate that focal high-frequency ultrasound has the potential to achieve this in the future."
He adds in a statement: "However, we need to remember that this treatment was given to fewer than 50 men, without follow-up over a sustained period of time. We look forward to the results of further trials, which we hope will provide a clearer idea of whether this treatment can control cancer in the long term whilst ridding men of the fear that treating their cancer might mean losing their quality of life."