Radiotherapy (RT) is a mainstay of treatment for localised prostate cancer (PCa), yet its efficacy is fundamentally challenged by the inherent and adaptive heterogeneity of tumours. RT acts as a potent selective pressure on tumour cell populations, driving phenotypic plasticity and fostering the evolution of resistant subclones. Extracellular vesicles (EVs) have emerged as pivotal mediators in this adaptive process, serving as nanoscale messengers that transfer molecular cargo, including metabolites, metabolic regulators, and regulatory RNAs, to reshape the tumour microenvironment and propagate survival signals. At the same time, advances in metabolomics offer a powerful tool to elucidate the dynamic metabolic reprogramming orchestrated by EVs in response to RT. This review synthesises current knowledge on the interplay between RT, EV-mediated signalling, and metabolic adaptation in PCa. We examine how radiation stress alters EV biogenesis and cargo, and evaluate the evidence linking EV signalling to the glycolytic, lipid and amino acid pathways implicated in radioresistance, including emerging RT-ferroptosis-EV cross-talk. We argue that this EV-driven metabolic reprogramming is a potential mechanism underlying intra-tumoural heterogeneity and clonal evolution post-treatment. We organise these observations within a unifying framework in which EVs may act as drivers that actively confer radioresistance, amplifiers that propagate resistant phenotypes across the tumour, and readouts whose metabolite signatures report tumour state and RT response, which positions EV metabolomics as a candidate dynamic liquid biopsy and a plausible therapeutic target, and we consider how single-EV analysis could resolve the subclonal heterogeneity central to this model. Finally, we highlight the technical and conceptual challenges in the field that must be addressed to define whether EV metabolomics can provide clinically meaningful insight into RT-driven tumour evolution and support future precision oncology strategies.

prostate cancer, radiotherapy, extracellular vesicles, phenotypic plasticity, metabolic reprogramming