Diagnostic evaluation of patients with a brain mass as the presenting manifestaton of cancer

Background: Patients with a newly detected brain mass and no history of cancer often undergo extensive diagnostic testing in search of a systemic primary neoplasm prior to selection of a biopsy site, potentially leading to unnecessary expense and delay. We sought patterns in the evaluation of these patients to allow rapid selection of a biopsy site. Methods: We compared the diagnostic evaluation of 176 patients with newly detected brain masses who were ultimately determined to have a metastatic or primary lesion. Results: In 88 patients presenting with brain metastasis, lung cancer was markedly overrepresented as a primary tumor, occurring in 82% of patients. Brain MRI and chest CT together identified the site for diagnostic biopsy in all except for two of the 176 patients. One-half of the patients with metastasis had brain biopsy as the primary diagnostic procedure, with 80% undergoing a craniotomy rather than needle biopsy. The initial management decision in the majority of metastasis patients was whether to perform a craniotomy for resection of tumor. Whereas patients with single and cerebellar lesions were most likely to undergo craniotomy, the extent of systemic disease did not affect the decision to recommend a neurosurgical procedure. The average time to biopsy for patients with metastatic and primary tumors was 4.7 days and 6.0 days. In this retrospective population, we estimated that evaluation with brain MRI and chest CT, followed by an early neurosurgical decision, could reduce the time to diagnosis by at least 10%. Conclusions: Chest CT and brain MRI, if used together as initial diagnostic studies, would have identified a biopsy site in 97% of patients with a newly detected brain mass.