When is a little treatment too much treatment? That curiosity was the foundation of a new study out of McGill University Health Center in Montreal.[i] The research team followed 157 patients who had been diagnosed with unilateral prostate cancer (cancer on one side of the gland only) and followed by repeat biopsy for a median of 5.4 years. The average patient age at diagnosis was 67, and all of them went on active surveillance (AS). The majority (92%) had a Gleason score < 6. The researchers used repeat biopsies to assess whether any of the patients were developing unfavorable disease features (UDF), meaning their PCa was worsening to a point where treatment should be considered. At the heart of the study was the question: What is the probability that a hemiablation at the outset (following diagnosis) would be of greater benefit than AS?
While the researchers speak of hemiablation as if it were a “focal” treatment, it is not. Hemiablation comes from two words: hemi means half, and ablation means destruction. In other words, the half of the gland containing PCa is destroyed. It is usually done by cryotherapy, or freezing, under ultrasound guidance. Because of the iceball size needed to destroy half the gland, hemiablation destroys the nerve bundle, which controls sexual function, on that side. It can also affect urinary function if the ice is applied close to the apex, where it can damage the very small muscle that regulates urination. In comparison to radical prostatectomy, when done by an expert it has a lower side effect profile, but it is not a treatment that targets just the tumor.
What the research team found was that fewer than half of the patients developed UDF. In fact, depending on the various ways they defined UDF (variables included PSA, number of biopsies taken, and maximum cancer percentage on any biopsy core) anywhere from 10-47% of patients were considered to be at greater risk. The team concluded that “careful patient selection for focal therapy should be performed to avoid subjecting patients to unnecessary treatment.”
I agree with the conclusion, especially if the alternative to AS is hemiablation. The team rightly sees it as overtreatment, especially if there’s only a single small focus of disease. Many of our patients who have been diagnosed elsewhere were told that they were candidates for AS. However, they were not willing to live with a cancer, however small, that could potentially develop UDF. They preferred to nip it in the bud, so to speak, with focal laser ablation—a truly focal therapy. The practice of monitoring AS patients by means of repeat biopsies is loaded with risks: developing scar tissue that can confound imaging, infection, complications, and pain. Focal laser ablation can take a load of fear off a patient’s mind. Perhaps hemiablation can, too, but at what potential price? For the right patient, our laser ablation offers minimal risk with maximum benefit.
[i] Barayan GA, Aprikian AG, Hanley J, Kassouf W, Brimo F, Bégin LR, Tanguay S. Outcome of repeated prostatic biopsy during active surveillance: implications for focal therapy. World J Urol. 2014 Nov 12. [Epub ahead of print]
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