The Impact of Extent of Ablation on Survival of Patients With Newly Diagnosed Glioblastoma Treated With Laser Interstitial Thermal Therapy: A Large Single-Institutional Cohort

Abstract

BACKGROUND Upfront laser interstitial thermal therapy (LITT) can be used as part of the treatment paradigm in difficult-to-access newly diagnosed glioblastoma multiforme (ndGBM) cases. The extent of ablation, though, is not routinely quantified; thus, its specific effect on patients' oncological outcomes is unclear. OBJECTIVE To methodically measure the extent of ablation in the cohort of patients with ndGBM and its effect, and other treatment-related parameters, on patients' progression-free survival (PFS) and overall survival (OS). METHODS A retrospective study was conducted on 56 isocitrate dehydrogenase 1/2 wild-type patients with ndGBM treated with upfront LITT between 2011 and 2021. Patient data including demographics, oncological course, and LITT-associated parameters were analyzed. RESULTS Patient median age was 62.3 years (31-84), and the median follow-up duration was 11.4 months. As expected, the subgroup of patients receiving full chemoradiation was found to have the most beneficial PFS and OS (n = 34). Further analysis showed that 10 of them underwent near-total ablation and had a significantly improved PFS (10.3 months) and OS (22.7 months). Notably, 84% excess ablation was detected which was not related to a higher rate of neurological deficits. Tumor volume was also found to influence PFS and OS, but it was not possible to further corroborate this finding because of low numbers. CONCLUSION This study presents data analysis of the largest series of ndGBM treated with upfront LITT. Near-total ablation was shown to significantly benefit patients' PFS and OS. Importantly, it was shown to be safe, even in cases of excess ablation and therefore could be considered when using this modality to treat ndGBM.

In Reply: The Impact of Extent of Ablation on Survival of Patients With Newly Diagnosed Glioblastoma Treated With Laser Interstitial Thermal Therapy: A Large Single-Institutional Cohort

“…We agree with Awan et al 1 regarding the potential of excess ablation contribution to glioblastoma patients' overall survival and progression-free survival, possibly similar to supramaximal resection accumulating data. In our study, no benefit regarding those oncological parameters was demonstrated.…”

“…We appreciate the letter to the editor submitted to the Neurosurgery journal recently by Awan et al 1 This letter addresses several important aspects of our work 2 that are to be clarified accordingly.…”

“…In our study, no benefit regarding those oncological parameters was demonstrated. 2 Future studies of a large number of patients with glioblastoma undergoing upfront laser interstitial thermal therapy are needed to further evaluate this theory.…”

Letter: The Impact of Extent of Ablation on Survival of Patients With Newly Diagnosed Glioblastoma Treated With Laser Interstitial Thermal Therapy: A Large Single-Institutional Cohort

“…13 Despite the growing literature supporting supramaximal resection in GBM, 14 ExA in this cohort did not show a positive effect on PFS or OS because of higher tumor residual in this group. 1 Therefore, we believe that optimization of the LITT-associated parameters to match ExA with supramaximal resection can potentially improve the LITT-related PFS and OS. The incorporation of preoperative mapping and intraoperative neuromonitoring in LITT planning may further contribute to achieve this goal.…”

“…Kaisman-Elbaz et al 1 also report 84% of patients with excess ablation (ExA) (between 0.25 and 35.3 cc) performed with no neurological deficit. At least 75% of this cohort had lesions which were in deep or eloquent regions.…”