MET-6 Neoadjuvant fractionated stereotactic radiotherapy followed by piecemeal resection for metastatic brain tumor

BACKGROUND: Large brain metastases which require resection are treated with surgery followed by whole brain radiation therapy or postoperative stereotactic radiosurgery (SRS). Recently a novel strategy using neoadjuvant stereotactic radiosurgery (Na-SRS) followed by surgery was reported, demonstrating lower rates of postoperative leptomeningeal dissemination (LMD) and symptomatic radiation necrosis (RN). We treated with neoadjuvant fractionated stereotactic radiotherapy (Na-fSRT) followed by surgery for large brain metastasis with piecemeal resection. METHODS: Twelve patients received Na-fSRT followed by surgery between July 2019 and April 2021. Na-fSRT dose was based on lesion size and was standard dosing. Surgery generally followed within 7 days after radiotherapy. RESULTS: The mean age was 68 years (51–79). Sixteen men and five women. Mean follow-up period was 8.5 months (1–24.9). Primary were lung; 10 (NSCLC; 9, SCLC (recurrence); 1), esophagus; 3, colon; 2, melanoma; 2, kidney; 2 (recurrence1), uterus body; 1, and liver; 1. The median maximum tumor diameter was 3.6 cm (2.6–4.9). Median PTV, GTV volume were 21.7ml, 15.5ml, respectively. The median fSRT dose was 30Gy/5fr, and the median time from fSRT to surgery was 4 days (1–7). As preoperative adverse event, intracranial hypertension and partial seizure grade 2 (CTCAE ver.5) were occurred, but controlled with steroid and osmotic diuretics and anticonvulsant. Grade 3 and more adverse events were not occurred. Gross total removal was performed in 95.2%. Event cumulative incidence as follows: cavity local recurrence 4.8% (subtotal removal case); distant brain failure 33%; LMD 4.8%; and symptomatic RN 0%. The median intracranial progression free survival was 7 months, and median overall survival was 8.4 months. CONCLUSIONS: Na-fSRT followed by piecemeal resection is safety and feasible, and may have therapeutic value for deep large brain metastasis and eloquent lesion. Further prospective investigations in multi-institutional settings are warranted.