Metastasis accounts for 90% of cancer related deaths and the transition from localized to metastatic disease represents a paradigm shift as the strategy for therapy changes from aggressive and localized, to systemic and generally palliative. Despite its importance, metastatic spread remains poorly understood, and a contributing factor to this is the multi-step nature of the process involving cancer cell dissemination, secondary growth, dormancy, heterogeneity and clonal evolution. For such a multi-faceted process, only through a combination of experimental and theoretical investigations can we hope to gain a comprehensive mechanistic understanding. In this nascent field, where there is so much yet unknown, development of sound theory is necessary if we are to interpret existing data, and in addition it has the power to guide experimentalists in their work. The aim of this mini-symposia is to provide a forum for discussing recent theoretical advances in the mathematical modeling metastasis, and will cover a range of techniques such as PDEs, ODEs and stochastic models, aimed at interrogating different parts of the metastatic cascade.