Incidence of initial spinal metastasis in glioblastoma patients and the importance of spinal screening using MRI.

PURPOSE: Intracranial glioblastomas with simultaneous spinal lesions prior to chemoradiation therapy or craniotomy, defined as initial spinal metastasis, are not well understood. Herein, we investigated intracranial glioblastoma and demonstrated the importance of spinal screening using gadolinium enhanced spinal magnetic resonance imaging (Gd-MRI).

METHODS: Consecutive adult patients with intracranial glioblastoma were treated between 2010 and 2014 and received spinal screening using Gd-MRI. Spinal screening was performed regardless of spine-related symptoms, and patients presenting with and without initial spinal metastasis (spinal and non-spinal groups, respectively) were compared based on patient demographics, tumor characteristics, radiological and molecular features, and overall survival (OS).

RESULTS: During the study period, 116 glioblastoma cases were treated and 87 of these (76%) underwent spinal screening. Among these patients, 11 (13%) were included in the spinal group, and 76 (87%) were included in the non-spinal group. All patients of the spinal group were free of symptoms related to spinal lesions. Compared with the non-spinal group, intracranial lesions of the spinal group presented higher incidences of intracranial dissemination and were located at subventricular zones (P = 0.0012 and 0.020, respectively). MIB-1 labeling index, molecular alterations such as IDH1 mutation, TERT promoter mutation, and immunoreactivity of ATRX and MGMT did not differ between two groups. OS was significantly shorter in the spinal group than in the non-spinal group (P = 0.0054).

CONCLUSIONS: This study revealed a relatively high incidence of spinal metastasis. A subset of glioblastoma patients benefited from spinal screening, through which early detection of asymptomatic spinal metastasis was achieved.