V4-02: Gold Nano-Particle Directed Focal Laser Ablation for Prostate Tumors using US and MR Fusion Technology

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INTRODUCTION

: A growing collective proficiency in multiparametric magnetic resonance imaging (mpMRI) and targeted biopsies for prostate cancer (PCa) screening has given way to an increasing interest in the application of these technologies for targeted therapy. Various targeted therapies have been developed and evaluated; however, these treatments focus energy at a region of the prostate, as opposed to directly at the tumor. Gold nanoparticle (GNP) therapy is a novel treatment that results in tumor-specific ablation, sparing surrounding tissue and structures. Herein, we report the first two cases in the world using gold nanoparticle-directed focal laser ablation of prostate tumors targeted with ultrasound (US) and MR/US fusion technology.

METHODS

Patients were enrolled in a phase II trial, &[prime]A Study of MRI/US Fusion Imaging and Biopsy in Combination with Nanoparticle Directed Focal Therapy for Ablation of Prostate Tissue.&[prime] Treatment and follow up plan are as follows: intravenous infusion on day 0, which allows GNP deposition into the tumors with the goal of achieving a 15.2 µg/cc tumor concentration required for excitation/ablation. On day 1, the patient presents for focal laser excitation of the GNPs. Laser catheters are placed using a combination of US and a transperineal electromagnetic-tracked MR/US fusion device (Invivo, Gainesville, FL). 48 hours’ post-ablation, the patient is imaged, fig 1, followed by re-imaging and MR/US fusion guided biopsy (FBx) at 3 months. All patient demographics, clinical variables, and complications were recorded.

RESULTS

To date, 2 patients have been enrolled in the trial, both with localized Gleason 7 PCa diagnosed using MR/US FBx. Mean age was 67 + 4.3 years and mean prostate specific antigen was 6.1 + 0.06 ng/ml. The mean tumor volume was 0.40 + 0.05 cc with a solitary lesion in each patient. The mean PSA decrease was 3.6 + 0.6 ng/ml, a 40.9% decrease at 1 month. No short-term complications were observed. The first patient underwent a follow up FBx at 3 months with no detectable cancer.

CONCLUSION

Increasing interest in image guidance technologies and focal therapies has sparked a new generation of PCa treatment modalities. We have demonstrated the first safe and effective use of ultra-focal therapy using MR/US fusion technology in concert with GNP directed therapy to treat prostate tumors.

Funding: Funded Trial by Nanonspectra Biopsciences