Attributes of brain metastases from breast and lung cancer.

Background: Most brain metastases arise from breast and lung cancers. Few studies compare the brain regions they involve, their numbers and intrinsic attributes.

Methods: Records of all patients referred to Radiation Oncology for treatment of symptomatic brain metastases were obtained. Computed tomography (n = 56) or magnetic resonance imaging (n = 72) brain scans were reviewed.

Results: Data from 68 breast and 62 lung cancer patients were compared. Brain metastases presented earlier in the course of the lung than of the breast cancer patients (p = 0.001). There were more metastases in the cerebral hemispheres of the breast than of the lung cancer patients (p = 0.014). More breast than lung cancer patients had cerebellar metastases (p = 0.001). The number of cerebral hemisphere metastases and presence of cerebellar metastases were positively correlated (p = 0.001). The prevalence of at least one metastasis surrounded with >2 cm of edema was greater for the lung than for the breast patients (p = 0.019). The primary tumor type, rather than the scanning method, correlated with differences between these variables.

Conclusions: Brain metastases from lung occur earlier, are more edematous, but fewer in number than those from breast cancers. Cerebellar brain metastases are more frequent in breast cancer.