Figure 11 shows the effect of the tumor position on the displacements between pre- and post-surgical data. An interesting effect can be noticed: the distribution of displacements on the breast is dependent on the breast quadrant where the tumor is positioned. Larger displacements are centered around the tumor, vanishing as the distance to the tumor center increases. Hence, a feature space transformation might be helpful to describe the displacements distribution as function of the tumor position. In alternative, Euclidean and polar distance to tumor could benefit the modelling of the points displacements.