Magnetic Resonance-Guided Laser Ablation Improves Local Control for Postradiosurgery Recurrence and/or Radiation Necrosis

BACKGROUND: Enhancing lesions that progress after stereotactic radiosurgery are often tumor recurrence or radiation necrosis. Magnetic resonance-guided laser-induced thermal therapy (LITT) is currently being explored for minimally invasive treatment of intracranial neoplasms. OBJECTIVE: To report the largest series to date of local control with LITT for the treatment of recurrent enhancing lesions after stereotactic radiosurgery for brain metastases. METHODS: Patients with recurrent metastatic intracranial tumors or radiation necrosis who had previously undergone radiosurgery and had a Karnofsky performance status of >70 were eligible for LITT. Sixteen patients underwent a total of 17 procedures. The primary end point was local control using magnetic resonance imaging scans at intervals of >4 weeks. Radiographic outcomes were followed up prospectively until death or local recurrence (defined as >25% increase in volume compared with the 24-hour postprocedural scan). RESULTS: Fifteen patients (age, 46-82 years) were available for follow-up. Primary tumor histology was non-small-cell lung cancer (n = 12) and adenocarcinoma (n = 3). On average, the lesion size measured 3.66 cm(3) (range, 0.46-25.45 cm(3)); there were 3.3 ablations per treatment (range, 2-6), with 7.73-cm depth to target (range, 5.5-14.1 cm), ablation dose of 9.85 W (range, 8.2-12.0 W), and total ablation time of 7.43 minutes (range, 2-15 minutes). At a median follow-up of 24 weeks (range, 4-84 weeks), local control was 75.8% (13 of 15 lesions), median progression-free survival was 37 weeks, and overall survival was 57% (8 of 14 patients). Two patients experience recurrence at 6 and 18 weeks after the procedure. Five patients died of extracranial disease progression; 1 patient died of neurological progression elsewhere in the brain. CONCLUSION: Magnetic resonance imaging-guided LITT is a well-tolerated procedure and may be effective in treating tumor recurrence/radiation necrosis.