Methods and apparatus quantify mass effect deformation in diagnostic images of patients demonstrating glioblastoma multiforme (GBM). One example apparatus includes an image acquisition circuit that acquires an image of a region of tissue demonstrating GBM pathology, a delineation circuit that segments a tumor region from the image, a pre-processing circuit that generates a pre-processed image by pre-processing the segmented image, a registration circuit that registers the pre-processed image with a template image of a healthy brain, a deformation quantification circuit that computes a set of differences between a position of a brain sub-structure represented in the registered image relative to the position of the brain sub-structure represented in the template image. Embodiments may include a classification circuit that classifies the region of tissue as a long or short-term survivor based, at least in part, on the set of differences.