V8-01: Focal Laser Ablation: Path to a clinic treatment for prostate cancer
Video
INTRODUCTION
Focal therapy of prostate cancer (CaP) is of keen interest, but data obtained via clinical trials are scarce. In this video, a path from targeted prostate biopsy to focal laser ablation (FLA) is demonstrated in 4 ensuing chapters: (1)Targeted Biopsy, (2) Preliminary Studies, (3) MRI-guided In-bore FLA, and (4) In-clinic FLA. Clinical trial data are included to support each step along the path.
METHODS
The path started with targeted biopsy via MRI/US fusion (Artemis), now performed in >1500 men at UCLA since 2009; these data laid groundwork for FLA. Preliminary studies using interstitial laser energy (in vitro and in vivo) were then assembled. After that, FLA in-bore was performed in 8 men, using direct MRI guidance for targeting and MR thermometry for temperature monitoring. Then, FLA was performed in-clinic in 10 men using (1) the fixed arm of the Artemis device for stabilization of the intra-prostatic laser fiber, (2) MRI/US fusion for tumor localization and targeting, and (3) direct thermal probes for safety monitoring during treatment. In-clinic FLA was performed using local anesthesia + midazolam.
RESULTS
Initial work with targeted biopsy showed that index CaP lesions could be accurately defined and other serious lesions ruled out in >80% of cases (Filson, CA, 2015). Preliminary studies showed that interstitial laser energy could ablate prostate tissue safely and effectively. Then, In-bore FLA was shown to be safe and effective in 8 men (Natarajan, J.Urol., 2016), but was cumbersome and expensive. Ultimately, the path led to an FDA-approved Phase I trial of out-of-bore (in-clinic) FLA in 10 men, all with intermediate-risk CaP. Short-term results were similar to those obtained in-bore, but simpler (3 vs 6 personnel), quicker (minutes vs hours), and less expensive (thousands vs tens of thousands of dollars). In-clinic FLA resulted in prostate-confined ablation zones averaging 4.3 cc (range, 2.1-6.0 cc); no man incurred incontinence or ED; and at 6-month targeted biopsies, successful ablation of intermediate-risk CaP was found in 6/10 men. Defining adequate margins of treatment remains a challenge.
CONCLUSION
A path from targeted biopsy to focal laser ablation of prostate cancer was followed; the potential for safe and effective treatment of intermediate-risk CaP ---under local anesthesia in a clinic setting---has been established.
Funding: Medtronic Navigation, Inc. via Physician-Sponsored Research Agreement with Regents of University of California and National Cancer Institute (R01CA158627).