gms | German Medical Science

Objective: Brain metastases of various cancers have an unfavorable prognosis. However, the treatment modalities, surgical resection and radiotherapy, have not changed in recent decades. The biological differences between the primary tumors are barely taken into account. Furthermore, the resection status is barely considered, despite the ongoing debate whether metastatic cells infiltrate the adjacent brain tissue. The only published prospective biopsy study demonstrated no evidence of infiltrating metastatic cells beyond the resection margin while two autopsy studies indicate the opposite. It is the aim of our prospective study to clarify this contradictory data.

Method: Up to ten biopsies per patient of the resection cavity wall were taken directly after gross total resection of brain metastasis and analyzed by suitable IHC for infiltrating tumor cells afterwards.

Results: Twenty-six patients were included and 127 biopsies were taken. In 42 biopsies (33.1%) infiltrating tumor cells were detectable, 16 of the 26 patients (61.5%) revealed infiltrating tumor cells in at least in one biopsy sample. Furthermore, the infiltration depended on the primary tumor type with NSCLC carcinoma having the most pronounced infiltration, mamma carcinoma and rectal cancer ((cluster/cohort infiltration) melanoma (angio-cooptive infiltration and renal carcinoma show no infiltration. Infiltration had a significant impact on the prognosis.

Conclusions: First, our results prove the existence of infiltrating metastatic cells. Moreover, this infiltration has a prognostic value and is tumor type dependent. The results suggest, that at least those brain metastases with pronounced infiltration should be resected more aggressively.