Study: 'Male Lumpectomy' Measures Up
Gary Onik, MD
SAN DIEGO—Focal cryoablation of prostate cancer—the so-called male lumpectomy—is associated with oncologic outcomes comparable with those achieved using more radical treatments, according to a study of patients who underwent the procedure and had up to 12 years of follow-up.
Focal cryoablation can be considered first-line treatment for men of all risk levels and particularly for patients who have failed radiation treatment, said study investigator Gary Onik, MD, professor of interventional radiology at the University of Central Florida and director of the Center for Safer Prostate Cancer Therapy in Orlando.
“Our data show that focal cryoablation is as good for prostate cancer control as any other treatment, including surgery, radiation, and hormone therapy. But it is less invasive and traumatic for patients, preserves sexual and urinary function, and has no major complications,” Dr. Onik said. “Instead of removing, freezing, or using radiation on the entire prostate, interventional radiologists can find out where the cancer is and just destroy the cancer.”
With cryoablation, a probe is inserted through the skin. Using imaging to guide the needle to the tumor, the probe circulates extremely cold gas to freeze and destroy the cancerous tissue. This minimally invasive treatment targets only the cancer itself, sparing healthy tissue in and around the prostate gland rather than destroying it as traditional approaches do.
“Patients can go home on the day of the procedure, and the treatment can be repeated, if needed, in later years,” said Dr. Onik, who presented findings here at the Society of Interventional Radiology's 34th Annual Scientific Meeting.
“Any risks are fewer and lesser in intensity than with surgery. So, if you have the equivalent chance of the cancer's being cured with far less chance of complications, why wouldn't you choose it?”
Dr. Onik and his colleagues studied 120 men who had focal cryoablation during the past 12 years. Over a mean follow-up of 3.6 years, 112 patients (93%) had no evidence of cancer recurrence, even though 72 of these men were at medium to high risk for such recurrence.
“There were no local recurrences in the areas we treated, and with the ability to re-treat the 7% of patients who developed a cancer at a different site in the gland, cryoablation was 100% effective in local control of the patient's disease,” Dr. Onik said.
Additionally, 85% of the 120 men retained sexual function. Among patients who did not have previous prostate surgery, all remained continent.
According to Dr. Onik, an important component of focal cryotherapy is 3D transperineal mapping biopsy. Earlier detection of smaller tumors increases the likelihood that a small tumor can be treated using cryoablation. Using the 3D approach, Dr. Onik re-staged 180 patients who had previously undergone transrectal ultrasound (TRUS) mapping biopsies.
“When we re-staged the men, we found that 22% of them had a higher Gleason score, meaning that they had a more aggressive cancer than was first thought from their original biopsy. The 3D mapping biopsy provided lifesaving information,” Dr. Onik said. “The data are unequivocal.”
Using 3D mapping, more than 55% of men who were diagnosed with cancer on only one side of the prostate gland with a TRUS biopsy were found to have undetected cancer on the other side.
With 3D mapping, a grid placed over the perineum allows a clinician to accurately map the location of each biopsy core removed. The cores are taken through the skin rather than through the rectum, allowing many more cores to be removed, about 50 compared with 10-12 during a TRUS biopsy. The mapping grid enables clinicians to get a more precise fix of a tumor's location.
“Based on our results, it is now the obligation of the urological community to carry out prospective randomized trials comparing focal therapy with robotic radical prostatectomy and radiation.” Dr. Onik said. The American Urological Association recently issued a best practice statement indicating that cryotherapy is an option for men who have clinically organ-confined prostate cancer of any grade and no metastases.