EPID-12. TREATMENT OUTCOMES OF MIDLINE GLIOMAS WITH H3K27 M: OUR BARROW NEUROLOGICAL INSTITUTE EXPERIENCE

Abstract

Abstract BACKGROUND H3 K27M glioblastoma is an aggressive grade IV tumor located in midline structures, added in 2016 by the WHO. Current outcomes are poor. The rarity of these tumors presents a challenge for definitive research on developing optimal treatments. METHODS We conducted a case series of 12 patients at the Barrow Neurological Institute who were diagnosed with biopsy-proven H3 K27M glioblastoma. The clinical status of these patients was followed from dates of first and last contact. Factors included first line treatment, best response to first line treatment, recurrences, second line treatments, response assessment criteria for all treatment rounds, any discovered metastases, and vital status by date of last contact. RESULTS Of the initial 12 patients, 5 were lost to follow-up before meaningful clinical outcomes could be recorded. Of the remaining 7, all underwent temozolomide and radiation as components of first-line treatment. After first-line treatment, 1/7 (14.2%) had partial response, 3/7 (42.8%) had stable disease, and 3/7 (42.8%) had progressive disease. 4 patients elected to undergo second line treatment: 2 underwent bevacizumab with lomustine, 1 underwent bevacizumab and irinotecan, and 1 underwent surgery with carmustine. Of the 2 who underwent bevacizumab and lomustine, 1 (50%) improved from progressive to stable disease and 1 (50%) stayed at stable disease. Of the 1 patient who underwent bevacizumab and lomustine, outcome worsened from stable to progressive disease. Of the 1 patient who underwent surgery and carmustine, outcome improved from progressive to stable disease. CONCLUSIONS H3 K27M is a highly aggressive tumor with poor outcomes. This case series demonstrates that multiple treatment rounds with chemotherapy and radiation therapy may benefit patients, with bevacizumab/lomustine and surgery/carmustine appearing to lead to promising outcomes. Further research is needed to establish evidence-based protocols so quality of life and survival time in these patients may improve.