Palliative Resection of Metastatic Brain Tumors Previously Treated by Stereotactic Radiosurgery

BACKGROUND Therapeutic approaches to brain metastases include surgery, whole-brain radiotherapy, stereotactic radiosurgery (SRS), and combination therapy. Recently, postoperative or preoperative SRS draws more attention to reduce postoperative recurrence in brain metastases. The goal of this study is to review surgical outcome of patients who had been treated by SRS, and to discuss the effectiveness of preoperative SRS. METHODS From 2009 to 2015, 174 patients were treated by SRS for brain metastases, and among these 50 patients underwent surgery. Eighteen patients underwent surgery after SRS, and 14 had oligometastases. The patients' median age at the time of surgery was 56 years (range, 34-84 years). The median follow-up duration was 16.5 months (range, 4-47 months). Pathological findings were classified as follows; radiation necrosis (Group I, n=3), mixed type (Group II, n=2), and tumor-dominant group (Group III, n=9). We compared surgical outcome in respect of steroid, mannitol dosage, Karnofsky performance scale, and pathological subgroups. RESULTS The median overall survival was 11 months (range, 2-40 months). Six, 12 and 24 months survival rate was 64.3, 42.9, and 28.6%, respectively. Improvement of Karnofsky performance score was achieved in 50% after surgery. The overall survival of Group I (26.6 months) was longer than the other groups (11.5 months). Additionally the patients were able to be weaned from medications, such as steroid administration after surgery was reduced in 10 cases, and mannitol dosage was reduced in 6 cases. Time interval within 3 months between SRS and surgery seemed to be related with better local control. CONCLUSION Surgical resection after radiologically and symptomatically progressed brain metastases previously treated with SRS seems to be effective in rapid symptom relief and provides an improvement in the quality of life. A short time interval between SRS and surgical resection seems to be associated with good local tumor control.