SAN DIEGO – A minimally invasive prostate cancer treatment called focal cryoablation may replace traditional approaches such as radical prostatectomy and radiation treatment, experts said during the 34th annual scientific meeting of the Society of Interventional Radiology (SIR; Fairfax, Virginia), being held here this week.
But the new approach may face resistance due to "economic forces," according to Gary Onik, interventional radiologist and director of the Center for Safer Prostate Cancer Therapy in Orlando, Florida.
While radical prostatectomy and radiation have become major profit centers for many hospitals, doctors can only make about $1,200 off a focal cryoablation, Onik said during a Monday press conference. Even so, if emerging data on focal cryoablation are reproduced and validated by the medical community, it "changes the game completely" and "essentially removes" the more serious treatments from the equation, he said.
While the idea of cryoablation in prostate cancer is not new, focal cryoablation – which Onik calls a "male lumpectomy" – involves using a new 3-D diagnostic approach to pinpoint the tumor and then applying freezing gas administered through an image-guided needle in a targeted manner that spares as much of the prostate gland and its neurovascular bundles as possible.
Data presented at the conference showed that 112 of 120 patients (93%) treated with focal cryoablation had stable levels of prostate-specific antigen (PSA) with no evidence of cancer after a median follow-up time of 3.6 years, despite the fact that 72 of the patients were judged to have a medium to high risk for recurrence.
Additionally, all patients maintained their continency and 85% maintained their potency – problems common after more serious prostate cancer treatments.
Onik also noted that the focal cryoablation approach provided superior treatment of extra-capsular extension, can be utilized in patients who have failed radiation, can be repeated if needed, and is both less invasive and less expensive than other approaches.
While focal cryoablation offers a middle ground between "watchful waiting" and more severe whole-organ treatments, he noted that it is not just for patients with mild disease. He presented a case study of a hormone-resistant patient with a Gleason score of 10 and PSA level of 200 ng/mL who responded to the approach.
Focal cryoablation is made possible thanks to a new imaging technique known as 3-D transperineal mapping, which Onik also highlighted at the conference.
The current gold standard for prostate cancer diagnosis and staging, transrectal ultrasound or TRUS, is not accurate and leads to inappropriate treatment decisions, Onik said. The new 3-D approach, which allows the removal of about five times as many biopsy cores and precisely maps each, reveals the location of the tumor and allows for better staging and grading, he added.
To back his claims, Onik presented data from 180 prostate cancer patients who had undergone TRUS and were then re-tested with the 3-D approach. While TRUS had shown that all patients had unilateral prostate cancer, the 3-D scan revealed that 61% actually had bilateral disease. Additionally, 23% of patients were assigned a higher Gleason score after 3-D mapping.
Overall 70% of patients would have chosen a different course of treatment given the new information provided by the 3-D approach, he said.
"This should become a standard staging procedure for prostate cancer," Onik said.
Another potential prostate cancer diagnostic advance was published last month in Nature. A team from the University of Michigan (Ann Arbor), Pennsylvania State University (State College), and Metabolon (Durham, North Carolina) published data identifying the amino acid sarcosine as a biomarker that could potentially separate aggressive from indolent cancers. Their findings may one day lead to development of a urine test that could determine which patients can get by with "watchful waiting" and which require treatment.