Tumor-secreted extracellular vesicles (EVs) are critical mediators of intercellular communication between tumor cells and stromal cells in local and distant microenvironments. Accordingly ; EVs play an essential role in both primary tumor growth and metastatic evolution. EVs orchestrate multiple systemic pathophysiological processes ; such as coagulation ; vascular leakiness ; and reprogramming of stromal recipient cells to support pre-metastatic niche formation and subsequent metastasis. Clinically ; EVs may be biomarkers and novel therapeutic targets for cancer progression ; particularly for predicting and preventing future metastatic development.