Biocompatible gold nanoparticles designed to convert near-infrared light to heat have been shown to safely and effectively ablate low- to intermediate-grade tumours within the prostate, according to a study conducted at the Icahn School of Medicine and published in the journal Proceedings of the National Academy of Sciences.

This treatment could offer patients a targeted therapy option that would preserve critical structures within the prostate, thus avoiding side effects associated with whole-gland treatment such as prostatectomies.

Prostate cancer is the second leading cause of cancer deaths in men in the United States.

11 percent of men will be diagnosed with the disease in their lifetime.

Removal or other whole-gland treatment of the prostate carries risks of urinary incontinence and erectile dysfunction.

However, technological advances have provided clinicians with options for focal therapies with fewer complications.

The Principal Investigator and lead author, Ardeshir Rastinehad, DO, Associate Professor of Urology, and Radiology, at the Icahn School of Medicine at Mount Sinai, invented the technique used in the clinical trial to target and treat the prostate cancer cells using a custom-built MR US fusion guided platform in collaboration with Philips Healthcare. 

The therapy uses gold-silica nanoshells (GSN), particles Dr. Halas invented that are composed of a silica core and a gold shell with a diameter of 150 nanometers.

The nanoshells are designed to absorb energy from near-infrared light and convert it to heat, resulting in selective hyperthermic cell death, without affecting adjacent non-tumorous tissue.

The treatment was effectively demonstrated in previous cell studies and animal models.

Following treatment, the particles are cleared through the liver, while some remain sequestered in the liver and spleen.

There are no known side effects.

Sixteen men aged 58 to 79 with low- to intermediate-grade prostate cancer (Gleason score of 4 3) received GSN infusion.

All were diagnosed and treated at The Mount Sinai Hospital using a targeted biopsy technique called magnetic resonance-ultrasound fusion imaging, which uses MRI technology to extract a tissue sample directly from the tumour.

Patients underwent GSN infusion and high-precision laser ablation, and received an MRI of the prostate 48-72 hours after the procedure, MRI-targeted fusion biopsies at 3 and 12 months, and a standard biopsy at 12 months.

Patients were discharged on the same day as the procedure after several hours of monitoring.

GSN-mediated focal laser ablation was successful in 87.5 percent of lesions treated at one year of follow-up.

The goal of researchers was to find an eradication of cancer cells during biopsy.

"Gold-silica nanoshells infusion allows for a focused therapy that treats the cancer, while sparing the rest of the prostate, thus preserving a patient's quality of life by reducing unwanted side effects, which could include erectile dysfunction and/or the leakage of urine," said Dr. Rastinehad.

"Mount Sinai's interventional urology program is research-driven and offers patients minimally invasive treatment therapies that improve quality of life," said Ash Tewari, MBBS, MCh, Chair of the Department of Urology at the Mount Sinai Health System and the Kyung Hyun Kim, MD Professor of Urology at the Icahn School of Medicine at Mount Sinai. "Dr. Rastinehad's gold nanoparticle research shows that patients are not only benefiting from this treatment, but also experiencing minimal side effects."

Source: The Mount Sinai Hospital / Mount Sinai School of Medicine