Ultrasound-Activated Microbubbles for Precision Chemo-Radioenhancement in Prostate Cancer: Sonoporation, Therapeutic Synergy, and Translational Pathways

Background/Objectives: Radiotherapy and docetaxel are mainstays of prostate cancer management, yet both are constrained-radiotherapy by normal-tissue tolerance and docetaxel by systemic toxicity and acquired resistance. Ultrasound-activated microbubbles (USMB) convert acoustic energy into spatially localized mechanical bioeffects that can potentiate both. This review examines USMB as a precision chemo- and radio-enhancer in prostate cancer. Methods: We conducted a scoping review with mechanistic and translational synthesis, informed by PRISMA-ScR reporting principles. We identified sources through a structured bibliographic search and supported it with source-level verification. Heterogeneity in model systems, acoustic parameters, treatment regimens, and outcomes precluded meaningful quantitative pooling; we therefore synthesized the evidence narratively. Results: Two distinct mechanisms recur: sonoporation-cavitation-driven permeabilization that increases intracellular docetaxel delivery and acid sphingomyelinase (ASMase)-mediated ceramide-driven endothelial perturbation that sensitizes tumor vasculature to radiation. In prostate models, the three modalities enhance one another, and the triple combination produces the largest reported increases in clonogenic death, apoptosis, and regression in selected immunodeficient PC3 models. These effects were achieved at reduced experimental drug and radiation doses, a potential dose-sparing benefit that remains a preclinical hypothesis. Human data, although still outside the prostate, provide early support for feasibility and acceptable safety in selected USMB-enhanced settings. Conclusions: The rationale is coherent and the preclinical prostate signal consistent, but the evidence remains predominantly preclinical, PC3-dominated, and heterogeneous. USMB is best understood not as a drug-delivery technique but as a tunable sensitization platform whose outcome depends on acoustic dose, vascular state, and sequencing; parameter standardization, prostate-specific delivery, and cautious early-phase trials remain prerequisites for translation.