Feasibility of MRI-Guided Transperineal Implantation of Microdevices for Drug Delivery and Response Assessment in Prostate Cancer.

Background: Prostate cancer (PCa) treatment often involves systemic therapies with varying mechanisms of action, affecting individuals differently. Implantable microdevices (IMDs) are designed to test multiple drugs within a patient's tumor, but the feasibility of MRI-guided placement in PCa has not been evaluated.

Purpose: To provide proof of concept for placing IMDs into lesions with MRI guidance to predict patient-specific responses to therapies.

Study Type: Prospective.

Population: Fifteen participants undergoing prostatectomy for PCa.

Field Strength/sequence: 3T MRI With T2-weighted (T2W).

Assessment: In-bore MRI-targeted placement of IMDs was performed. Intra-procedural MRI scans were reviewed by a radiologist, using needle artifacts on T2W images to guide IMD placement. A genitourinary pathologist performed Gleason scoring around the IMDs. Drug response analysis included Enzalutamide + Nivolumab, Enzalutamide + Docetaxel, and single-agent Enzalutamide.

Statistical Tests: Mann-Whitney U test for continuous variables, p < 0.05 for significance.

Results: Of 53 IMDs implanted into suspicious lesions in 14 participants, 48 (90%) were successfully placed within the lesions. The average distance from the needle tip to the tumor was 8.32 ± 4.02 mm. Larger lesion size (p = 0.009) and lower prostate imaging-reporting and data system score (p = 0.031) were significantly associated with successful IMD placement. Of the 53 IMDs, 49 (92.4%) were retrieved for histopathology and drug response analysis. In four participants, Gleason scores around the device were lower than preplacement biopsy in two and equal in two. Additionally, drug analysis in one patient demonstrated the feasibility of drug response analysis, revealing differences in apoptotic index, lymphocyte infiltration, dysplastic cell composition, and cellular profiles for each treatment. No complications or adverse events occurred.

Conclusion: IMDs can be effectively and safely placed in prostate lesions using MRI guidance, with feasible histological and drug response analyses.

Evidence Level: 2. Technical Efficacy: Stage 1.