Login to Access Video or Poster Abstract: V8-01
Sources of Funding: Medtronic Navigation, Inc. via Physician-Sponsored Research Agreement with Regents of University of California and National Cancer Institute (R01CA158627).

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.

Conclusions

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).