Introduction: Laser-induced interstitial thermal therapy (LITT) has evolved as a new, minimally-invasive therapy in the armamentarium against brain cancer. LITT is cytoreductive, and effects of therapy are immediate in contrast to radiosurgery, which make take up to several weeks. Mechanistically, high temperature (>70C) induces cellular necrosis and apoptosis. Furthermore, thermal ablation is purported to open the peritumoral blood-brain barrier (BBB), but little is known in quantification of BBB disruption (BBBD).

Methods: A retrospective series of LITT patients at KUMC were identified. We have noted the impact of cerebral edema following LITT. We retrospectively reviewed pre-operative, intra-operative, and post-operative imaging for presence of BBBD and cerebral edema. In addition, a review of the literature was done in effort to quantify BBBD following LITT.

Results: Twelve patients were identified in our series at KUMC. Post-LITT edema was surprisingly long-lasting duration of 2-6 weeks. Two patients were re-hospitalized with altered mental status and malignant cerebral edema, responsive to steroids and hyperosmolar therapy. Radiologically, LITT showed restricted diffusion and peripheral enhancement up to several centimeters from the tumor’s edge, suggestive of BBBD. BBB disruption occurred at temperatures >40C. On review of the literature, 18 articles (174 patients) with high-grade gliomas were identified. One review paper, identified four out of 174 patients (2%) who encountered severe cerebral edema.

Conclusions: To our knowledge, no studies currently quantify BBBD following intracranial ablation in humans. Animal models estimate BBBD from days to several weeks. BBBD has exciting potential benefits including potentiation of adjuvant therapies. This has been demonstrated in animal models by increased locoregional passage of Evans blue dye and chemotherapy such as paclitaxel. Through a partnership with one stereotactic laser ablation company, we are completing a BBBD quantification study utilizing timed-MRI evaluation. A second-stage planned study involves post-LITT chemotherapy to evaluate the potentiation of chemotherapy following BBB disruption.

Patient Care: 1. We hope to quantify blood-brain barrier disruption and, as a result, be more able to predict those patients which may develop severe, symptomatic post-LITT edema. 2. As a second stage of study, we hope to enter patients into a randomized clinical trial of LITT + post-LITT chemotherapy versus chemotherapy alone to study the beneficial effects of LITT-induced blood-brain barrier opening.

Learning Objectives: 1. Participants should be able to familiarize themselves with laser ablation technology and its applications to brain tumors. 2. Participants will be introduced to the concept of blood-brain barrier opening and potential complications including severe cerebral edema.

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