Survival and Clinical Characteristics of Patients with Glioblastoma with Primitive Neuronal Component (P13-13.004)

Abstract

<h3>Objective:</h3> Evaluate the survival and clinical characteristics of patients with diagnosis of glioblastoma with primitive neuronal component (GBM-PNC) on initial diagnosis compared to patients diagnosed with GBM-PNC at recurrence following prior diagnosis of malignant glioma without primitive component. <h3>Background:</h3> A subset of malignant gliomas are found to have solid-looking primitive nodules which confer a diagnosis of glioblastoma with primitive neuronal component (GBM-PNC). At initial diagnosis, GBM-PNC is associated with increased responsiveness to platinum-based therapies and high rates of cerebrospinal fluid dissemination. It is unknown if the same characteristics and risks exist when primitive neuronal component develops at recurrence after an initial diagnosis with a malignant glioma. <h3>Design/Methods:</h3> The University of Washington pathology database was queried between the years of 2005 to 2021 to identify patients with a pathological diagnosis of GBM-PNC. Clinical and radiographic data were abstracted. Descriptive statistics and survival analysis were preformed. <h3>Results:</h3> 20 patients with diagnosis of GBM-PNC were identified and 16 had appropriate clinical information for inclusion. 11 patients were diagnosed with GBM-PNC at initial surgery and 6 were diagnosed at surgery for presumed recurrent malignant glioma. For patients found to have GBM-PNC at recurrence, the median overall survival was 40months compared to only 17months for patients diagnosed at initial surgery. Patients diagnosed at recurrence, also had longer time to first progression of 26.5months compared to 12months for patients initially diagnosed with GBM-PNC. The 4 patients who had intracranial progression leading to diagnosis of GBM-PNC all had cystic appearance on MRI. 33% of patients diagnosed with GBM-PNC at recurrence developed leptomeningeal dissemination. <h3>Conclusions:</h3> Patients who are diagnosed at GBM-PNC at recurrence of a prior malignant glioma have improved survival compared to patients who have a primitive neuronal component of the malignant glioma diagnosed at initial resection. This pathology was associated with a cystic radiographic appearance when intracranial. <b>Disclosure:</b> Dr. McGranahan has nothing to disclose. Patrick Cimino has nothing to disclose. Ms. Costanza has nothing to disclose.