Gold nanoshell-localized photothermal ablation of prostate tumors in a clinical pilot device study

Significance Prostate cancer is the most common nonskin cancer in the United States, where approximately 1 in 9 men will be diagnosed in their lifetime. The prostate is near several vital structures, such as the urethra and neurovascular bundle, and whole gland treatments for prostate cancer can disrupt normal urinary, bowel, and sexual functioning. Here we report the initial results of a clinical trial for nanoparticle-based photothermal cancer therapy. The trial was designed to perform ultrafocal photothermal ablation of cancerous tumors within the prostate. Gold-silica nanoparticles designed to absorb near-infrared light at wavelengths of high tissue transparency provide a highly localized light-based strategy for the treatment of prostate cancer, with substantially reduced risks for deleterious treatment-related side effects. Biocompatible gold nanoparticles designed to absorb light at wavelengths of high tissue transparency have been of particular interest for biomedical applications. The ability of such nanoparticles to convert absorbed near-infrared light to heat and induce highly localized hyperthermia has been shown to be highly effective for photothermal cancer therapy, resulting in cell death and tumor remission in a multitude of preclinical animal models. Here we report the initial results of a clinical trial in which laser-excited gold-silica nanoshells (GSNs) were used in combination with magnetic resonance–ultrasound fusion imaging to focally ablate low-intermediate-grade tumors within the prostate. The overall goal is to provide highly localized regional control of prostate cancer that also results in greatly reduced patient morbidity and improved functional outcomes. This pilot device study reports feasibility and safety data from 16 cases of patients diagnosed with low- or intermediate-risk localized prostate cancer. After GSN infusion and high-precision laser ablation, patients underwent multiparametric MRI of the prostate at 48 to 72 h, followed by postprocedure mpMRI/ultrasound targeted fusion biopsies at 3 and 12 mo, as well as a standard 12-core systematic biopsy at 12 mo. GSN-mediated focal laser ablation was successfully achieved in 94% (15/16) of patients, with no significant difference in International Prostate Symptom Score or Sexual Health Inventory for Men observed after treatment. This treatment protocol appears to be feasible and safe in men with low- or intermediate-risk localized prostate cancer without serious complications or deleterious changes in genitourinary function.