Laser Interstitial Thermal Therapy for Radiation Necrosis/Adverse Inflammatory Responses to SRS - Case Report and Literature Review

Brain metastases are the most common type of intracranial tumor [1-4], and confer a dismal prognosis; despite aggressive secondary and even tertiary resections, stereotactic radiosurgery, high-dose external beam radiotherapy, and multi-mechanistic chemotherapy delivered at toxic doses, median survival ranges from 2 to 25 months [5]. The morbidity of intracranial tumors is substantial, and arises not only from neurological deficits associated with direct brain compression or invasion, but also secondary to systemic and local treatment modalities. In particular, radiation necrosis, a common sequelae of stereotactic radiosurgery (SRS), results in difficult-to-control mass effect and perilesional edema, severely limiting a patient’s ability to function and reducing quality of life [6-8]. Truly, “radiation necrosis” is a misnomer, as the process is more accurately an adverse inflammatory response post-stereotactic radiotherapy (AIRS). The mainstay of treatment is high-dose corticosteroids, which themselves generate a litany of poorly-tolerated symptoms, including hyperglycemia, elevated infection risk, impaired wound healing, osteopenia and suppressed adrenal function [9]. Alternative strategies such as therapeutic anticoagulation, bevacizumab [10], hyperbaric oxygen [11], and even resection [7] have been attempted with limited success, and AIRS remains a substantial therapeutic challenge.