Efficacy of Laser Interstitial Thermal Therapy (LITT) for Newly Diagnosed and Recurrent IDH Wild-type Glioblastoma

Background

Treatment options for unresectable new and recurrent glioblastoma remain limited. Laser ablation has demonstrated safety as a surgical approach to treat primary brain tumors. The LAANTERN prospective multicenter registry (NCT02392078) data was analyzed to determine clinical outcomes for patients with new and recurrent IDH wild-type glioblastoma.

Methods

Demographics, intraprocedural data, adverse events, KPS, health-economics, and survival data were prospectively collected then analyzed on IDH wild-type newly diagnosed and recurrent glioblastoma patients who were treated with laser ablation at 14 US centers between January 2016 and May 2019. Data was monitored for accuracy. Statistical analysis included individual variable summaries, multivariable differences in survival, and median survival numbers.

Results

A total of 29 new and 60 recurrent IDH wild-type WHO grade 4 glioblastoma patients were treated. Positive MGMT promoter methylation status was present in 5/29 of new and 23/60 of recurrent patients. Median physician-estimated extent of ablation was 91-99%. Median overall-survival was 9.73 months (95% confidence interval: 5.16, 15.91) for newly diagnosed patients and median post-procedure survival was 8.97 (6.94, 12.36) months for recurrent patients. Median overall-survival for newly diagnosed patients receiving post-LITT chemo/radiation was 16.14 months (6.11, not reached). Factors associated with improved survival were MGMT promoter methylation, adjuvant chemotherapy within 12 weeks, and tumor volume <3cc.

Conclusions

Laser ablation is a viable option for patients with new and recurrent glioblastoma. Median overall survival for IDH wild type newly diagnosed glioblastoma is comparable to outcomes observed in other tumor resection studies when those patients undergo radiation and chemotherapy following LITT.

LMD-10. The role of immune checkpoint inhibitors in leptomeningeal disease: a systematic review

Background

Leptomeningeal disease (LMD) is a devastating complication of advanced malignancy with a poor prognosis and limited therapeutic options. Whether immune checkpoint inhibitors (ICIs) alter disease course is unknown.

Methods

We searched PubMed, EMBASE, Scopus, Cochrane, and clinicaltrials.gov according to PRISMA guidelines to analyze the therapeutic role and toxicity profiles of ICIs in the management of LMD. Studies reporting clinical outcome data of patients with LMD treated with ICIs were included. A comprehensive review of clinical characteristics and survival analysis was conducted.

Results

We included 14 studies encompassing 61 patients. The median age at LMD diagnosis was 57 years (female=63.9%). Lung cancer (44.3%), breast cancer (27.9%), and melanoma (23.0%) were the most frequent primary tumors. Parenchymal brain metastases occurred in 37 patients, mostly treated with radiotherapy (83.3%). LMD most frequently presented with headache (42.1%) and was diagnosed by MRI findings (leptomeningeal T1-contrast enhancement: 96.7%) and/or positive cerebrospinal fluid cytology (86.5%). Patients received ICIs for a median duration of 7 months (range, 0.5–58.0): pembrolizumab (49.2%), nivolumab (32.8%), and/or ipilimumab (18.0%). The most common concurrent LMD treatments were radiotherapy (54.7%) and steroids (35.7%). Radiological responses at 6-months were complete (33.3%) and partial response (12.5%), stable disease (33.3%), and progression (20.8%). 22 patients developed ICI-related adverse events, mostly mild (100%) and uncommonly severe (15.6%). Median progression-free survival was 5.1 months, median overall survival was 6.3 months, and 12-month survival was 32.1%. Survival was correlated with ICIs (P=0.042), but not with primary tumors (P=0.144). Patients concurrently receiving steroids showed worse survival (P=0.040), with a median overall survival of 1.9 months.

Conclusion

ICI therapy shows promise and appears to be well-tolerated in patients with LMD. Concurrent use of steroids is associated with worse survival. The role of ICIs in the multimodal management of LMD and their combination with steroids requires further analysis.