Spatial Brain Distribution of Intra-axial Metastatic Lesions in Breast and Lung Cancer Patients

The frequency of the diagnosis of brain metastases has increased in recent years, probably due to an increased diagnostic sensitivity. Site predilection of brain lesions in oncological patients at the time of onset, may suggest mechanisms of brain-specific vulnerability to metastasis. The aim of the study is to determine the spatial distribution of intra-axial brain metastases by using voxel-wise statistics in breast and lung cancer patients. For this retrospective cross-sectional study, clinical data and MR imaging of 864 metastases at first diagnosis in 114 consecutive advanced cancer patients from 2006 to 2011 were included. Axial post-gadolinium T1 weighted images were registered to a standard template. Binary lesion masks were created after segmentation of volumes of interest. The voxel-based lesion-symptom mapping approach was used to calculate a t statistic describing the differences between groups. It was found that the lesions were more likely to be located in the parieto-occipital lobes and cerebellum for the total cohort and for the non small cell lung cancer group, and in the cerebellum for the breast cancer group. The voxel-wise inter-group comparisons showed the largest significant clusters in the cerebellum for the breast cancer group (p < 0.0008) and in the occipital lobe (p = 0.02) and cerebellum (p = 0.02) for the non small cell lung cancer group. We conclude a non-uniform distribution of metastatic brain lesions in breast and lung cancer patients that suggest differential vulnerability to metastasis in the different regions of the brain.