Metastasis from glioblastoma multiforme: a meta-analysis

OBJECTIVE: Extracranial metastases of glioblastoma multiforme (GBM) are rare due to the short survival experienced by the patients. Therefore, the natural history of GBM metastases remains elusive. The identification of clinical factors promoting GBM metastases may help elucidate the mechanisms of tumor cell invasion in the brain. The aims of this study were to perform a meta-analysis evaluating the survival, characteristics, prognostic factors, and predictors of treatment outcome in patients with metastatic GBM and describe a case of metastatic extracranial GBM. METHODS: We report the case of a patient diagnosed with GBM metastatic to the lungs and the results of a meta-analysis of 114 other cases of metastatic GBM identified through a MEDLINE and BIREME search. RESULTS: The mean age of the patients was 38.2 +/- 16.1 years and 70.4% were male. The time elapsed between the identification of the metastasis and death was significantly increased in patients undergoing surgery (p=0.019), whereas the time from the diagnosis of the primary tumor to death was significantly increased in patients receiving radiation therapy (p=0.050). The time elapsed from metastasis to death and diagnosis to death was significantly longer in patients receiving chemotherapy (p<0.001 and p=0.027, respectively). The liver was the metastatic site associated with the shortest time elapsed from diagnosis to death (p=0.024). CONCLUSIONS: In GBM, surgical resection is important in reducing the risk of metastasis, and chemotherapy and radiation therapy help to prolong survival in metastatic GBM. Metastases to the liver are associated with shorter survival compared with metastases to other sites.