Incidence of local in-brain progression after supramarginal resection of cerebral metastases

Microsurgical circumferential stripping of intracerebral metastases is often insufficient in achieving local tumor control. Supramarginal resection may improve local tumor control. A retrospective analysis was performed for patients who underwent supramarginal resection of a cerebral metastasis by awake surgery with intraoperative cortical and subcortical stimulation, MEPs, and SSEPs. Supramarginal resection was achieved by circumferential stripping of the metastasis and additional removal of approximately 3 mm of the surrounding tissue. Pre- and postsurgical neurological status was assessed by the NIH Stroke Scale. Permanent deficits were defined by persistence after 3-month observation time. Supramarginal resection of cerebral metastases in eloquent brain areas was performed in 34 patients with a mean age of 60 years (range, 33-83 years). Five out of 34 patients (14.7 %) had a new transient postoperative neurological deficit, which improved within a few days due to supplementary motor area (SMA) syndrome. Five out of 34 patients (14.7 %) developed a local in-brain progression and nine patients (26.4 %) a distant in-brain progression. Supramarginal resection of cerebral metastases in eloquent locations is feasible and safe. Safety might be increased by intraoperative neuromonitoring. The better outcome in the present series may be entirely based on other predictors than extend of surgical resection and not necessarily on the surgical technique applied. However, supramarginal resection was safe and apparently did not lead to worse results than regular surgical techniques. Prospective, controlled, and randomized studies are mandatory to determine the possible benefit of supramarginal resection on local tumor control and overall outcome.