A paper on line in the journal Radiology offers some of the earliest, formally published data from a major academic medical center on the clinical use of focal laser ablation in the treatment of low-risk prostate cancer.
One can argue over whether actually treating men with such low-risk disease in this way is a good or a less good thing to be doing. However, at least the team at the University of Chicago seems to have set out to do this according to good scientific research practice!
Oto et al. set out to assess the feasibility and safety of magnetic resonance (MR) imaging-guided, laser-based thermotherapy in men with clinically low-risk prostate cancer and an evident, concordant lesion at biopsy and on MR imaging.
The research team carried out a Phase I clinical trial in which they conducted transperineal, MR imaging-guided focal laser ablation on just 9 patients with a Gleason score of 7 or less in three or fewer cores limited to one sextant and obtained under transrectal ultrasonography (TRUS)-guided biopsy and a concordant lesion at MR imaging. The team collected an extensive range of data before, during, and after patient treatment, specifically including the International Prostate Symptom Score (IPSS) and the Sexual Health Inventory for Men (SHIM) score.
Here are their results:
- Treatment was successfully completed in all 9 patients
- The duration of the procedure ranged from 2.5 to 4.0 hours.
- The overall time to complete the procedure dropped with surgeon experience
- The average time for actual laser ablation of the tumor was just 4.3 min.
- Immediate, contrast-enhanced, post-treatment MR imaging showed a hypovascular defect in 8/9 patients.
- No patient appears to have had a major complication or side effect of treatment.
- Self-resolving perineal abrasion (a wearing away of some skin on the perineum) occurred in 1/9 patients.
- Focal paresthesia (“pins and needles”) of the glans penis also occurred in 1/9 patients.
- The average (mean) IPSS score at baseline was 5.8 ± 5.3.
- The average (mean) SHIM score at baseline was 19.0 ± 8.0.
- Short-term follow-up was conducted at 3 and 6 months post-treatment.
- Average changes in the IPSS and SHIM scores were not significantly different from zero during patient follow-up (P = 0.18 to 0.99).
- MR imaging-guided biopsy of the ablation zone showed no cancer in 7/9 patients (78 percent) and Gleason grade 6 cancer in 2/9 patients (22 percent).
The research team concludes that transperineal, MR imaging-guided, focal laser ablation appears to be a feasible and safe form of focal therapy for the treatmenmt of clinically low-risk prostate cancer.
Some additional information is available in a media release issued by the University of Chicago Medicine. According to that media release, a phase II trial of this procedure is now underway, and the research team intends to enroll a further 27 patients. Details about this Phase II trial are available on the ClinicalTrials.gov web site.
The “New” Prostate Cancer InfoLink would point out that it is arguable whether all of the patients in this trial were strictly “low-risk.” Apparently at least a couple of them had Gleason 7 disease. We assume that these were patients who had small amounts of Gleason 3 + 4 = 7 disease, however, and there is good reason to believe that such patients could be treated successfully with focal therapy. What is more worrying about this study is that 2/9 patients were still found to have some Gleason 6 disease at short-term follow-up. If this type of treatment is to become routine, one should be able to expect that efficacy should be well over 90 percent, with a very low risk for side effects.