Prostate-sparing treatment using nanoparticles shows promise

A new technique using gold-silica nanoparticles to perform ultrafocal photothermal ablation of prostate cancer tumors seems feasible, safe, and relatively free of serious complications or life-altering changes in genitourinary function for men with low- or intermediate-risk localized prostate cancer, according to a recent study.

In a pilot device study published in the Proceedings of the National Academy of Sciences (Aug. 26, 2019 [Epub ahead of print]), researchers reported on 16 patients with low- or intermediate-risk localized prostate cancer who had the gold-silica nanoshell (GSN)-mediated focal laser ablation technique (AuroLase Therapy). The approach involves infusing prostate tumors with biocompatible gold silica nanoshells and performing high-precision laser ablation.

GSN-mediated focal laser ablation successfully eradicated cancer cells in 87.5% of lesions treated at 1 year of follow-up and resulted in about a 42% reduction in patients’ PSAs at 3 months.

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Researchers have since completed enrollment for the first 45 patients to test the primary endpoint of tumor ablation-data that will take about 1 year to mature, according to principal investigator and lead author Ardeshir (Art) Rastinehad, DO, of Icahn School of Medicine at Mount Sinai, New York. Dr. Rastinehad invented the technique used in the AuroLase Therapy trial.

“What is really exciting about this research is it is the first human use of nanoparticle-directed photothermal therapy. It has taken 20 years of research to finally make it to human trials, and we are having very promising results. There are endless possibilities for clinical applications in other tumors,” Dr. Rastinehad told Urology Times.

Dr. Rastinehad began his work on the technique as a fellow working at the National Institutes of Health and Philips Healthcare on a transperineal MR/ultrasound fusion-guided biopsy device.

“This biopsy approach allows patients to have a targeted biopsy with little to no risk of infection. It is also a very stable platform that allows the prior biopsy data to be retargeted for treatment. In our study, we used the fusion biopsy information to target specific areas of the prostate-thus creating a focal therapy approach for prostate tumors,” Dr. Rastinehad said.

The next part of the project involved using gold silica nanoshells to target the tumors, creating a tumor-specific ablation site.

“The big difference between laser ablation and AuroLase-mediated ablation is that a typical laser generates heat, which kills tissue. In our study, we use a low-temperature laser that sends light energy through the tissue to excite the Auroshells to create heat and thus kill prostate tumors,” he said.

Next:Who is most likely to benefit?Prostate cancer patients most likely to benefit from GSN-mediated focal laser ablation are men with focal lesions that have been diagnosed using multiparametric MRI and have no disease outside of the prostate, according to Dr. Rastinehad.

“This would not be applicable to patients with advanced, or metastatic, disease,” Dr. Rastinehad said.

According to Dr. Rastinehad, it’s important for urologists to know that the diagnosis of prostate cancer is changing with use of high-quality multiparametric MRI of the prostate and targeted biopsies. This could change a conversation urologists often have with their prostate cancer patients when they ask their doctors: “If you see it on MRI and then completed a targeted biopsy, why can’t you just treat the spot? Why would I have to have my entire prostate out if the cancer is only in one area?”

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Treatment options like this would do precisely that, targeting therapy, preserving critical structures within the prostate and avoiding side effects associated with whole-gland treatment, such as prostatectomies, according to Dr. Rastinehad.

Dr. Rastinehad said he explains to patients that this is a new area of study in urology, still under investigation, but results are encouraging and could shift the paradigm for some prostate cancer patients to prostate-sparing treatments.

The trial is expanding to multiple U.S. sites and will soon include sites in Europe.

“I think what is really important is changing how we evaluate men at risk for prostate cancer and start integrating MR imaging and targeted biopsy into the pathway,” Dr. Rastinehad said. “Until this happens, patients will not have even have the option to consider focal therapy options and enrollment in trials like mine.”

Dr. Rastinehad receives research support from and is a consultant for Philips Healthcare and Nanospectra.