CLINICAL STUDY Spatial brain distribution of intra-axial metastatic lesions in breast and lung cancer patients Carlo Cosimo Quattrocchi • Yuri Errante • Chiara Gaudino • Carlo Augusto Mallio • Alessandro Giona • Daniele Santini • Giuseppe Tonini • Bruno Beomonte Zobel Received: 16 March 2012 / Accepted: 6 July 2012 / Published online: 18 July 2012 Ó Springer Science+Business Media, LLC. 2012 Abstract The frequency of the diagnosis of brain metas- tases 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 con- secutive 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 meta- static brain lesions in breast and lung cancer patients that suggest differential vulnerability to metastasis in the dif- ferent regions of the brain. Keywords Brain metastasis Á Voxel-wise statistics Á Lung cancer Á Breast cancer Introduction Brain metastases (BMs) occur in 20–40 % of adult cancer patients with an incidence of [ 170.000 new cases per year in the United States [1, 2]. Thus, they represent the most common tumors of the central nervous system (CNS) [3]. The frequency of the diagnosis of BMs has increased in recent years probably due to an increased sensitivity of imaging techniques [1, 4, 5], particularly when lesions are located in the posterior fossa or they are very small [6]. The most common primary tumors responsible for BMs are lung cancer in men and breast cancer in women. Two main biological mechanisms have been considered in the last 120 years to explain the occurrence of brain metastasis: mechanical trapping of tumor emboli and the ‘‘seed and soil’’ hypothesis [7]. In fact, BMs are often found at the grey-white matter junction and at the watershed regions of the brain parenchyma; these are the areas where the calibre of blood vessels changes suddenly with consequent trap- ping of tumor emboli [8]. The ‘‘seed and soil’’ hypothesis [7] states that successful outgrowth of metastatic tumors depends on cross-talk and permissible interactions between Electronic supplementary material The online version of this article (doi:10.1007/s11060-012-0937-x) contains supplementary material, which is available to authorized users. C. C. Quattrocchi (&) Á Y. Errante Á C. Gaudino Á C. A. Mallio Á A. Giona Á B. B. Zobel Unit of Radiology, CIR-Center for Integrated Research in Biomedicine and Bioengineering, University Campus Bio-Medico di Roma, via Alvaro del Portillo, 21, 00128 Rome, Italy e-mail: c.quattrocchi@unicampus.it D. Santini Á G. Tonini Unit of Oncology, CIR-Center for Integrated Research in Biomedicine and Bioengineering, University Campus Bio-Medico di Roma, via Alvaro del Portillo, 21, 00128 Rome, Italy 123 J Neurooncol (2012) 110:79–87 DOI 10.1007/s11060-012-0937-x