Nanoparticle-directed focal therapy feasible in men with prostate cancer

Use of nanoparticle-directed focal laser ablation results in the successful treatment of several patients with localized prostate cancer (PCa), as confirmed by negative magnetic resonance (MR)/ultrasound (US) fusion biopsy of the treated lesion and a systematic biopsy.

Using the Focal Therapy Society Delphi criteria, nanoparticle ablation has shown efficacy in 73 percent of men with PCa at 3 and 12 months after treatment.

“Urinary function and overall quality of life (QOL) were well preserved after treatment,” the researchers said. In addition, “[s]exual function has completely recovered by the 12-month post-treatment visit.”

Forty-six men with localized PCa in Gleason Grade Group 1 to 3 were enrolled in this prospective, open-label, single-arm, multicentre study. They received a single infusion of gold nanoparticles, followed by MR/US fusion‒guided laser excitation of the target tissue to bring photothermal ablation.

The effectiveness of prostate tissue ablation was assessed using MRI at 48 to 96 hours, 3 months, and 12 months post-treatment. A targeted fusion biopsy of the lesion was performed at month 3, while a targeted fusion biopsy and standard templated biopsy were carried out at month 12.

Researchers determined treatment success based on a negative MR/US biopsy outcome within the treated area.

Forty-four men with 45 lesions completed treatment with nanoparticle infusion and laser ablation. At baseline, the mean prostate-specific antigen (PSA) level was 9.5 ng/mL. This significantly decreased to 5.9 ng/mL at 3 months and 4.7 ng/mL at 12 months (p<0.0001). [J Urol 2024;212:862-872]

Of the 44 patients who completed treatment, 29 (66 percent) achieved oncologic success at 3 months and 32 (73 percent) at 12 months. Successful treatment was confirmed with negative MR/US fusion biopsies within the ablation zone.

Among Gleason Grade Group, maximum lesion diameter on MRI, prostate volume, and Prostate Imaging Reporting and Data System scoring, the maximum lesion diameter predicted the likelihood of treatment failure at 12 months (p=0.046).

These findings suggest that “nanoparticle-directed ablation of prostate tissue using near infrared light is safe and well tolerated.”

Urinary, sexual functions

“The promise of focal therapy lies in its ability to provide cancer control/cure while preserving sexual and urinary function,” the researchers said.

“Functional outcomes after nanoparticle-directed ablation were similar to those after other focal therapy modalities, with the exception of one outlier due to poor patient selection,” they added.

Previous studies have shown that voiding symptom scores did not significantly differ before and after focal high-intensity focused US and irreversible electroporation. However, these scores improved following focal cryotherapy. [J Urol 2019;202:717-724; J Urol 2014;192:749-753; Eur Urol Oncol 2020;3:283-290]

“Voiding symptom improvement can be correlated with extent of tissue ablation, as might be expected, and this was also seen anecdotally after larger-volume nanoparticle–directed ablations,” according to the researchers.

Likewise, sexual function worsened after focal high-intensity focused US and irreversible electroporation, but not after cryotherapy. In the current study, the mean Sexual Health Inventory for Men score among sexually active men with PCa decreased significantly.