The role of laser interstitial thermal therapy in enhancing progression‐free survival of difficult‐to‐access high‐grade gliomas: a multicenter study

Surgical extent‐of‐resection has been shown to have an impact on high‐grade glioma ( HGG ) outcomes; however, complete resection is rarely achievable in difficult‐to‐access ( DTA ) tumors. Controlled thermal damage to the tumor may have the same impact in DTA ‐ HGG s. We report our multicenter results of laser interstitial thermal therapy ( LITT ) in DTA ‐ HGG s. We retrospectively reviewed 34 consecutive DTA ‐ HGG patients (24 glioblastoma, 10 anaplastic) who underwent LITT at Cleveland Clinic, Washington University, and Wake Forest University (May 2011–December 2012) using the NeuroBlate ® System. The extent of thermal damage was determined using thermal damage threshold ( TDT ) lines: yellow TDT line (43°C for 2 min) and blue TDT line (43°C for 10 min). Volumetric analysis was performed to determine the extent‐of‐coverage of tumor volume by TDT lines. Patient outcomes were evaluated statistically. LITT was delivered as upfront in 19 and delivered as salvage in 16 cases. After 7.2 months of follow‐up, 71% of cases demonstrated progression and 34% died. The median overall survival ( OS ) for the cohort was not reached; however, the 1‐year estimate of OS was 68 ± 9%. Median progression‐free survival ( PFS ) was 5.1 months. Thirteen cases who met the following two criteria—(1) <0.05 cm 3 tumor volume not covered by the yellow TDT line and (2) <1.5 cm 3 additional tumor volume not covered by the blue TDT line—had better PFS than the other 21 cases (9.7 vs. 4.6 months; P  = 0.02). LITT can be used effectively for treatment of DTA ‐ HGG s. More complete coverage of tumor by TDT lines improves PFS which can be translated as the extent of resection concept for surgery.