Bone-marrow micrometastases in patients with brain metastases from epithelial cell tumours

Carcinoma that has metastasized to the central nervous system (CNS) poses a particular clinical problem regarding confirmation of the diagnosis and subsequent management. Prior to excision, thorough evaluation for coexisting systemic disease is essential, but current imaging techniques are limited by their spatial resolution and under-stage many patients. We evaluated the potential utility of bone-marrow evaluation for micrometastatic cells in patients with CNS metastasis. Bone-marrow aspirates were examined for cytokeratin-positive cells in 12 consecutive patients who presented with symptomatic space-occupying lesions of the CNS. These patients had previously undergone surgical excision of either gastrointestinal or breast cancers. All twelve had micrometastases in their bone marrow at the time of presentation with the CNS disease and all had a fatal outcome within 13 months. In nine of the 12 patients, bone-marrow micrometastases were the only evidence for systemic spread. Three patients had elevated serum tumour markers and two of these had radiologically detectable recurrence elsewhere. Bone-marrow micrometastases indicate concurrent systemic involvement and a poor prognosis. The results suggest that bone-marrow evaluation for systemic spread is a useful diagnostic adjunct and should be performed before considering diagnostic biopsy or excision.