We focus on the thin film equation with lower order "backwards" diffusion which can describe, for example, the evolution of thin viscous films in the presence of gravity and thermo-capillary effects, or the thin film equation with a "porous media cutoff" of van der Waals forces. We treat in detail the equationwhere ν = ±1, n > 0, M > m, and A 0. Global existence of weak nonnegative solutions is proven when m − n > −2 and A > 0 or ν = −1, and when −2 < m − n < 2, A = 0, ν = 1. From the weak solutions, we get strong entropy solutions under the additional constraint that m−n > −3/2 if ν = 1. A local energy estimate is obtained when 2 n < 3 under some additional restrictions. Finite speed of propagation is proven when m > n/2, for the case of "strong slippage", 0 < n < 2, when ν = 1 based on local entropy estimates, and for the case of "weak slippage", 2 n < 3, when ν = ±1 based on local entropy and energy estimates.