Histological changes associated with laser interstitial thermal therapy for radiation necrosis: illustrative cases

Abstract

BACKGROUND Patients with lung cancer and melanoma remain the two largest groups to develop brain metastases. Immunotherapy has been approved for treatment of stage IV disease in both groups. Many of these patients are additionally treated with stereotactic radiosurgery for their brain metastases during ongoing immunotherapy. Use of immunotherapy has been reported to increase the rates of radiation necrosis (RN) after radiosurgery, causing neurological compromise due to growth of the enhancing lesion as well as worsening of associated cerebral edema. OBSERVATIONS Laser interstitial thermal therapy (LITT) is a surgical approach that has been shown effective in the management of RN, especially given its efficacy in early reduction of perilesional edema. However, little remains known about the pathology of the post-LITT lesions and how LITT works in this condition. Here, we present two patients who needed surgical decompression after LITT for RN. Clinical, histopathological, and imaging features of both patients are presented. LESSONS Criteria for selecting the best patients with RN for LITT therapy remains unclear. Given two similarly sized lesions and not too dissimilar clinical histories but with differing outcomes, further investigation is clearly needed to identify predictors of response to LITT in the setting of SRS and immunotherapy-induced RN.

Safety and Efficacy of Laser Interstitial Thermal Therapy as Upfront Therapy in Primary Glioblastoma and IDH-Mutant Astrocytoma: A Meta-Analysis

“…Currently, there are multiple studies investigating the possibility of multimodal treatment in combination with LITT to provide synergistic delivery of other therapeutics to the tumor microenvironment [ 27 , 28 , 29 , 30 , 31 ]. Beyond just directed tumor cell death, LITT is also hypothesized to decrease the stability of tight junctions and the rate of transcytosis across the blood–blood–brain barrier (BBB) [ 32 , 33 ].…”