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

Abstract

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. 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. 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). 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 (range, 0.46-25.45 cm); 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. Magnetic resonance imaging-guided LITT is a well-tolerated procedure and may be effective in treating tumor recurrence/radiation necrosis.