Introduction: Laser interstitial thermotherapy (LITT) has begun to be used for radiation necrosis (RN) and shown promise as a novel clinical treatment. Cerebral RN lesions treated with LITT have demonstrated radiographic lesional control in short term follow-up. We review our experience and volumetrically analyze lesion size and edema following LITT.

Methods: Consecutive patients who were treated with LITT from January 2012 to January 2013 with a confirmatory biopsy consistent with radiation necrosis were included. A total of 6 patients were identified. The average age was 53 (range 29-72). Basic demographic data is included in Table 1. All postoperative brain MRI’s were reviewed. Medical Imaging Processing, Analysis, and Visualization Program version 7.0.1 (MIPAV, National Institutes of Health)) was used for volumetric analyses. The total lesion volume, enhancing volume, and surrounding edema was quantified. For patients who did not have appropriate imaging quality to undergo MIPAV analysis, we used bi-dimensional analysis.

Results: Four of the six patients had metastatic brain disease and previously undergone stereotactic radiosurgery to the treated lesion. Two patients had fractionated radiation therapy for treatment of glioblastoma and maxillary squamous cell carcinoma. Average clinical and radiographic follow-up period was 8 months (range 1-19months) and 8.5 months (range 1-19 months), respectively. Three of six patients continued on steroid treatment following ablation for other cerebral lesions. Volumetric analyses demonstrated a decrease in total and enhancing lesion volume in 5/6 patients (Figures 1+2). Surrounding T2 edema was decreased in 4/6 patients at last radiographic follow-up (Figure 3).

Conclusions: LITT for RN can result in symptomatic improvement for steroid refractory patients. Radiographic lesion analyses following treatment demonstrate lesion and T2 edema volume decrease over time in most patients. LITT can also be used for patients with RN following fractionated radiation.

Patient Care: LITT is a novel therapy with multiple neurosurgical applications. Recently, LITT has shown promise in treating radiation necrosis. Our study is the first to quantitatively analyze radiographic follow-up following LITT treatment for RN. These data will aid the clinician in understanding the expected radiographic characteristics of this new therapy and when to pursue another treatment modality.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the multiple uses of laser interstitial thermotherapy in treating patients with metastatic lesions 2) Discuss, in small groups, the pathophysiology of radiation necrosis and current theories on how laser thermal therapy can ameliorate the process 3) Identify an ideal patient candidate for LITT in treating RN

References: 1. Torres-Reveron J, Tomasiewicz HC, Shetty A, Amankulor NM, Chiang VL. Stereotactic laser induced thermotherapy (LITT): a novel treatment for brain lesions regrowing after radiosurgery. J. Neurooncol. 2013;113(3):495–503. 2. Patel N V, Jethwa PR, Barrese JC, Hargreaves EL, Danish SF. Volumetric trends associated with MRI-guided laser-induced thermal therapy (LITT) for intracranial tumors. Lasers Surg. Med. 2013;45(6):362–9.