  We introduce and analyze a phenomenological model for anti-angiogenic therapy
in the treatment of metastatic cancers. It is a structured transport equation
with a nonlocal boundary condition describing the evolution of the density of
metastasis that we analyze first at the continuous level. We present the
numerical analysis of a lagrangian scheme based on the characteristics whose
convergence establishes existence of solutions. Then we prove an error estimate
and use the model to perform interesting simulations in view of clinical
applications.
