SURG-11. LASER INTERSTITIAL THERMOTHERAPY (LITT) FOR NEWLY DIAGNOSED AND RECURRENT GLIOBLASTOMA: ASSOCIATION BETWEEN TIME TO INITIATION OF CHEMOTHERAPY POST-PROCEDURE AND OUTCOME

Abstract

BACKGROUND

LITT is used for cytoreduction of unresectable glioblastoma and is associated with blood brain barrier disruption with an increased permeability peak at 2 weeks. We investigated if time to initiation of chemotherapy post-LITT was associated with progression free survival (PFS) and overall survival (OS).

METHODS

Records of glioblastoma patients who underwent LITT at our institution between 2013-2017 were reviewed. Patients with inadequate follow-up or no further treatment after LITT were excluded. A time-to-event analysis was performed to investigate the association between PFS, OS and the time to initiation of chemotherapy after LITT.

RESULTS

The study included 21 patients; 17 recurrent glioblastoma (rGBM) (6 secondary glioblastoma), 4 newly diagnosed glioblastoma (nGBM). Median age was 53.6 (19.8-64.9) years. Three patients (14%) had isocitrate dehydrogenase (IDH)-1 mutation by immunohistrochemistry and two patients had unknown IDH status. Pre- and post-operative median KPS were 90 (60-100) and 80 (40-100) respectively. Eleven patients had difficulty weaning steroids (4 patients initiated steroids peri-operatively, 7 patients prior to surgery). For rGBM post-LITT median PFS was 3.36 months (95% CI (0.21, 0.51)) and median OS was 18.48 months (95% CI (0.66,NA)) with 5 deaths. Median PFS and OS for nGBM has not been reached. Eighteen patients (86%) received post-LITT chemotherapy of which eight initiated treatment >3 weeks post-LITTdue to poor functionality (6), pregnancy (1), and patient choice (1). Among the patients receiving chemotherapy, time to initiation of chemotherapy was not associated with PFS or OS. Chemotherapy in rGBM cohort included lomustine (6), temozolomide (5), bevacizumab (3), bevacizumab + lomustine (1), lapatinib (1), and Novo-TTF (1). Median time to initiation ofi bevacizumab (4 patients) after LITT was 30.5 (17-45) days, without complications.

CONCLUSIONS

LITT may be an effective cytoreductive treatment for glioblastoma. Timing of onset of chemotherapy after LITT for glioblastoma is not associated with PFS or OS.