BMET-22DIFFERENT SPATIAL DISTRIBUTION OF BRAIN METASTASIS FROM LUNG CANCER DEFINED BY EGFR MUTATION STATUS

PURPOSE: To test this hypothesis that different genetic backgrounds of lung cancers could affect spatial distribution of brain metastasis. EXPERIMENTAL DESIGN: CT or MR images of 200 patients with a total of 1033 treatment naive brain metastases from lung cancer were retrospectively collected. All images were deformed and standardized to MNI 152 standard human brain MRI. Locations of the lesions, depths of the lesions from brain surface, and sizes of the lesions after image standardization were analyzed and compared between histological subtypes of the primary lesion as well as EGRF mutation status. RESULTS: The posterior fossa, the anatomic watershed areas and the grey-white matter junction were confirmed to be predilection areas of lung cancer brain metastasis and brain metastasis with L858R occurred more often in caudate, cerebellum and temporal lobe than those with Ex19Del. Among adenocarcinoma lung cancer patients, depths of the lesions from brain surface were 15.7 ± 9.1mm for Ex19Del, 12.6 ± 8.5mm for L858R and 16.1 ± 8.5mm for WT. The lesions with L858R were located statistically significantly closer to the brain surface than the lesions with Ex19Del or WT (p = 0.0032 and p < 0.0001, respectively). On the other hand, there was no statistically significant difference in tumor size among different EGFR mutation status (p = 0.086). Furthermore, brain metastases of adenocarcinoma lung cancer patients with history of chemotherapy treatment were located statistically significantly deeper from brain surface (p = 0.0002). History of molecular targeted therapy did not have any effect on the depth of the lesion. CONCLUSIONS: This analysis is the first to reveal the relationship between tumor's molecular biological characteristics, namely EGFR mutation status and spatial distribution of brain metastases of lung cancer.