Advances of Drug-Loaded Microsphere Technology for Targeted Immunotherapy Against Prostate Cancer

Treating advanced prostate cancer presents challenges like therapy resistance and systemic toxicity. Combining drug-loaded microspheres with immunotherapy, such as PD-1 inhibitors, and targeted therapy like PARP inhibitors has transformed the treatment of prostate cancer. This review focuses on microcatheter-assisted techniques that allow for precise embolization using 100-300 μm microspheres and enable sustained drug release, resulting in an objective response rate (ORR) of 35-52% in clinical trials. Important advancements include pulsed injection protocols at 0.5 mL/min under cone beam CT (CBCT) guidance and biomarker-driven stratification, focusing on a PD-L1 combined positive score (CPS) of ≥10 and homologous recombination repair (HRR) mutations. The PROEMBOL trial shows a 98.1% rate of immediate hemostasis, and combination therapies with PARP inhibitors increase the median progression-free survival (PFS) to 14.2 months for patients with HRR mutations. Future efforts must prioritize standardized technical protocols and real-world validation of long-term outcomes.