A system for three-dimensional analysis of lesions in image data is disclosed. It comprises a lesion detection subsystem (1) for detecting individual lesions and three-dimensional positions of the individual lesions, based on e.g. breast image data (301). It comprises a cluster detection subsystem (2) for detecting a cluster of lesions (302), based on three-dimensional position information of lesions, and associating at least some of the individual lesions with the cluster of lesions (302), based on the three-dimensional positions of the individual lesions. The cluster detection subsystem (2) is arranged for detecting the cluster of lesions (302), based on the three-dimensional positions of the individual lesions. It comprises a cluster analysis subsystem (3) for analyzing the cluster of lesions (302).