TOPLINE

Laser interstitial thermal therapy (LITT) demonstrates low complication rates in a study of nearly 800 patients with brain tumors. Achieving a higher percentage of ablation in newly diagnosed glioblastoma was associated with better outcomes related to survival.

METHODOLOGY

• Deep-seated lesions including basal ganglia, thalamus, insula, and corpus callosum typically present with high surgical risk with open approaches, and survival outcomes are reduced when no cytoreduction is offered. Magnetic resonance imaging-guided LITT is a minimally invasive neurosurgical approach for ablating or cytoreducing intracranial tumors using hyperthermia.
• A total of 787 patients with primary (445) or metastatic (342) brain tumors treated with LITT using the Monteris NeuroBlate System were enrolled from 25 US centers between 2015 and 2023 in the LAANTERN prospective multicenter registry. 
• Researchers prospectively collected demographics, intraprocedural data, adverse events, survival data, and functional status over time, with follow-up extending up to 5 years post-LITT. 
• Extent of ablation (EOA) was determined by neurosurgeons based on postprocedural imaging and thermal-dose threshold coverage, categorized as < 10%, 10%-50%, 51%-90%, 91%-99%, and 100%. 
• Overall survival (OS) was defined as time from initial diagnosis to death for newly diagnosed primary tumors or time from LITT to death for recurrent disease, while progression-free survival (PFS) was defined as time from LITT to treated-lesion progression or death. 

TAKEAWAY

• Patients with newly diagnosed glioblastoma WHO grade 4 achieving ≥ 91% EOA demonstrated median PFS of 1.32 years vs 0.24 years with < 90% ablation (P < .0001) and median OS of 2.1 years vs 0.36 years (P < .0001). 
• For recurrent metastatic brain tumors, achieving 100% EOA resulted in median post-LITT OS of 2.8 years vs 1.3 years with < 99% ablation (P = .03), with smaller tumor volume (< 7.9 cc) associated with median PFS of 1.2 years vs 0.5 years (P = .001). 
• Patients with biopsy-proven radiation necrosis showed median OS of 4.18 years and median PFS of 1.89 years. 
• The median hospital stay was 32.4 hours with 62.6% of patients avoiding ICU admission, and seizure rates decreased from 54.1% at baseline to 11.0% at 6 months in primary tumor patients (absolute reduction 43.1%, P < .0001). 

IN PRACTICE

“The data from this largest, prospective LITT cohort support the consideration of LITT as a cytoreductive tool for patients with primary and metastatic tumor with short hospital stays, low complication rates, and preserved functional status. The EOA in glioblastoma and lesion volume in metastatic disease emerge as factors that may guide patient selection,” the authors of the study wrote.

SOURCE

The study was led by Eric C. Leuthardt, MD, MBA, Department of Neurosurgery, Washington University in St Louis. It was published online on August 17 in Journal of Clinical Oncology.

LIMITATIONS

As a prospective registry study without a control arm, direct comparisons to craniotomy outcomes must be made cautiously, and selection bias may affect the cohort as larger tumors may have been directed to open surgery while patients considered poor surgical candidates were potentially directed to LITT. Variations in LITT practice introduce heterogeneity into the dataset, and recurrence was determined clinically and radiographically per the treating physician, which could be subject to institutional variance. Rate of study completion declined over time with less than 50% completing 1-year follow-up and only 1%-2% of patients completing visits at 5 years, which may reflect high mortality, clinical deterioration, local follow-up after traveling to LITT institutions, and COVID pandemic impact. Not all recategorized patients had data available regarding TERT promoter mutation or EGFR gene amplification, and some may have been erroneously recategorized, potentially skewing survival analysis, while MGMT status was not available on all patients. The median lesion volumes differed substantially across EOA categories (51%-90%: 21.5 cc; 91%-99%: 12.8 cc; 100%: 8.2 cc), suggesting that baseline tumor characteristics may influence survival differences, and poor outcomes in the lower EOA group may reflect tumor biology, technical limitations of current LITT approaches for tumors > 15-20 cc, or unmeasured confounders rather than lack of treatment benefit.

DISCLOSURES

The LAANTERN registry was sponsored by Monteris Medical Corp. Leuthardt disclosed receiving consulting fees from Monteris Medical and holding stock and ownership interests in Kandu, Cordance Medical, Aurenar, Silent Surgical, and Sora Neuroscience. Veronica Chiang, MD, disclosed receiving consulting fees from Monteris Medical and MRI Interventions. Multiple other authors disclosed various relationships with Monteris Medical and other organizations. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.