gms | German Medical Science

Objective: Despite modern neurosurgical techniques and advances in radiotherapy, prognosis in patients with cerebral metastases is still dismal. Infiltrative processes into the surrounding parenchyma are known to produce peritumoral edema in gliomas. Recently, such infiltration was also described in cerebral metastases, which may influence outcome and may reduce the benefit of surgery. Thus, this study aimed at relating edema volume to outcome in cerebral metastatic lesions.

Method: Tumor volume and the volume of the surrounding edema was assessed in a retrospective analysis of 143 patients (76 males, 67 females), who underwent surgical resection of a metastasis, and were correlated to the overall survival. A dichotomous analysis was conducted, separating the tumors into those causing more or less edema than the tumor volume (coefficient 1<R<1).

Results: A median tumor volume of 15.2cc (range 0.8-90.8) was determined; while the median volume of the edema was measured with 40.4cc (range 0.0-179.9). 41 patients (28.6%) showed edema smaller than the tumor (R<1) whereas 102 patients (71.4%) demonstrated edema larger than the tumor volume (R>1). Subanalysis of the different primaries showed a significant negative correlation between the tumor volume and the overall survival in patients with lung cancer (p=0.000), melanoma (p=0.01) and lower gastrointestinal tract (p=0.02). Both the ratio between edema and tumor volume and the dichotomous analysis according to the R-value showed highly significant survival benefit for those patients with less edema (p=0,000 and p=0,002 respectively).

Conclusions: More pronounced peritumoral edema is associated with reduced overall survival in cerebral metastases. This correlation may be attributed to a more infiltrative growth pattern and/or differences in biological behaviour of the tumors. Further studies have to elucidate the underlying mechanisms in order to counteract them.