Laser interstitial thermal therapy followed by minimal-access transsulcal resection for the treatment of large and difficult to access brain tumors

Abstract

OBJECTIVE Laser interstitial thermal therapy (LITT), sometimes referred to as "stereotactic laser ablation," has demonstrated utility in a subset of high-risk surgical patients with difficult to access (DTA) intracranial neoplasms. However, the treatment of tumors larger than 10 cm³ is associated with suboptimal outcomes and morbidity. This may limit the utility of LITT in dealing with precisely those large or deep tumors that are most difficult to treat with conventional approaches. Recently, several groups have reported on minimally invasive transsulcal approaches utilizing tubular retracting systems. However, these approaches have been primarily used for intraventricular or paraventricular lesions, and subtotal resections have been reported for intraparenchymal lesions. Here, the authors describe a combined approach of LITT followed by minimally invasive transsulcal resection for large and DTA tumors. METHODS The authors retrospectively reviewed the results of LITT immediately followed by minimally invasive, transsulcal, transportal resection in 10 consecutive patients with unilateral, DTA malignant tumors > 10 cm³. The patients, 5 males and 5 females, had a median age of 65 years. Eight patients had glioblastoma multiforme (GBM), 1 had a previously treated GBM with radiation necrosis, and 1 had a melanoma brain metastasis. The median tumor volume treated was 38.0 cm³. RESULTS The median tumor volume treated to the yellow thermal dose threshold (TDT) line was 83% (range 76%-92%), the median tumor volume treated to the blue TDT line was 73% (range 60%-87%), and the median extent of resection was 93% (range 84%-100%). Two patients suffered mild postoperative neurological deficits, one transiently. Four patients have died since this analysis and 6 remain alive. Median progression-free survival was 280 days, and median overall survival was 482 days. CONCLUSIONS Laser interstitial thermal therapy followed by minimally invasive transsulcal resection, reported here for the first time, is a novel option for patients with large, DTA, malignant brain neoplasms. There were no unexpected neurological complications in this series, and operative characteristics improved as surgeon experience increased. Further studies are needed to elucidate any differences in survival or quality of life metrics.

Keywords: CUSA = cavitron ultrasonic surgical aspirator; DTA = difficult to access; GBM = glioblastoma multiforme; LITT; LITT = laser interstitial thermal therapy; NeuroBlate; OS = overall survival; PFS = progression-free survival; TDT = thermal dose threshold; WBRT = whole-brain radiation therapy; craniotomy; glioma; iMRI = intraoperative MRI; metastatic; stereotactic laser ablation; tumor.