Background: Enhancing lesions that progress after stereotactic radiosurgery (SRS) 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 SRS for brain metastases.
Methods: Patients with recurrent metastatic intracranial tumors or radiation necrosis who had previously undergone radiosurgery and KPS>70 were eligible for LITT. Sixteen patients underwent a total of 17 procedures. The primary endpoint was local control using MRI scans at intervals of >4 weeks. Radiographic outcomes were followed prospectively until death or local recurrence (defined as >25% increase in volume when compared with the 24-hour post-procedure scan).
Results: Fifteen patients (ages 46-82) were available for follow-up. Primary tumor histology was NSCLC (n=12) and adenocarcinoma (n=3). On average, the lesion size measured 3.66cm[superscript digit three] (range 0.46 – 25.45cm[superscript digit three]); there were 3.3 ablations per treatment (range 2-6), with 7.73cm depth to target (range 5.5cm-14.1cm), ablation dose of 9.85W (range 8.2-12.0watts), and total ablation time of 7.43 minutes (range 2-15 minutes). At median follow-up of 24 weeks (range 4-84 weeks), local control was 75.8% (13/15 lesions), median progression-free survival was 37 weeks and overall survival was 57% (8/14 patients). Two patients recurred at 6 weeks and 18 weeks post-procedure. Five patients died of extracranial disease progression; one died of neurologic progression elsewhere in the brain.
Conclusion: MRI-guided LITT is a well-tolerated procedure and may be effective in treating tumor recurrence/radiation necrosis.
From: Magnetic Resonance-Guided Laser Ablation Improves Local Control for Post-Radiosurgery Recurrence and/or Radiation Necrosis by Rao et al.