Vascularized tumor organoids as models for interpreting therapeutic response

Vascularized tumor organoids are increasingly used to model therapeutic response, yet their value depends not simply on vascular complexity, but on whether vascularization improves response attribution. This review examines two linked determinants of pharmacological interpretability, the endothelial interface and the transport barrier, and uses them to classify vascularized tumor organoid models by functional consequence. Across model classes, vascularization can reshape tumor state, define drug entry, constrain tissue penetration, and impose cargo- and cell-dependent access. Therapeutic response in these systems should therefore be interpreted not as a direct measure of intrinsic sensitivity, but as a composite readout shaped by exposure, penetration, and endothelial-state modulation.