Prognostic Factors and Treatment of Spinal Astrocytomas

A Multi-institutional Cohort Analysis

Yingjie Zou, MD; James Sun, BA; Yangying Zhou, BS; Harrison Xiao Bai, MD; Xiangyan Huang, MD; Ranjith Babu, MD; Alessandro Landi, MD; Kap Sum Foong, MD; Zishu Zhang, MD; John H. Woo, MD; Yongguang Tao, PhD; Xuejun Li, MD, PhD; Xiangqi Tang, MD, PhD; Bo Xiao, MD, PhD; Paul J. Zhang, MD; Li Yang, MD, PhD

Disclosures

Spine. 2018;43(10):E565-E573. 

In This Article

Abstract and Introduction

Abstract

Study Design. Retrospective cohort analysis of patients with spinal astrocytoma from multi-institutional data and the literature.

Objective. To determine the prognostic factors, treatment, and survival of patients.

Summary of Background Data. Our current understanding of the epidemiology, prognosis, and optimal treatment of spinal astrocytoma is limited. The literature is confined to case reports or small institutional case series.

Method. Patient demographics, tumor characteristics, treatments, and outcomes were extracted. Univariate Kaplan-Meier survival analysis was performed to identify prognostic factors followed by multivariate Cox proportional hazard analysis. Wilcoxon signed-rank test was performed on pre- and postoperational functional status as measured by McCormick score.

Results. Ninety-four patients from four institutions and 339 patients from the literature were included. For the multi-institutional cohort, WHO grade IV tumors had shorter progression-free survival (PFS) than those of lower grades, whereas gross total resection (GTR) (hazard ratio [HR]: 0.41, 95% confidence interval [CI]: 0.14–1.27, P = 0.124) trended toward longer PFS when compared to subtotal resection (STR). Age 18 years or older, paresthesia as a presenting symptom, and higher WHO grade were associated with shorter overall survival (OS), whereas thoracic tumor location when compared to cervical tumor location, biopsy when compared to STR, and radiotherapy (HR: 0.42, 95% CI: 0.20–0.88, P = 0.022) were associated with longer OS. For the literature cohort, GTR (HR 0.43, 95% CI: 0.24–0.77, P = 0.005) was associated with longer PFS when compared to STR, whereas higher WHO grade was associated with shorter PFS. Higher WHO grade and recurrence/progression were associated with shorter OS. Postoperative McCormick score was significantly higher than preoperative score (P < 0.001), but subgroup analysis of the change in McCormick score by extent of resection revealed no differences among groups (P = 0.551).

Conclusion. In patients with spinal astrocytomas, GTR likely resulted in longer PFS when compared to STR. Adjuvant radiotherapy appears to be effective in improving survival outcomes for high-grade tumors.

Level of Evidence: 4

Introduction

Intramedullary spinal cord tumors are relatively rare neoplasms that account for only 2% to 4% of central nervous system tumors.[1] Astrocytomas of the spinal cord, which have a reported incidence of 0.8 to 2.5 per 100,000 per year,[2] are the most common type of intramedullary spinal cord tumors in children, and the second most common in adults.[3,4] Of all astrocytomas arising in the central nervous system, 3% occur in the spinal cord.[5] The majority of spinal astrocytomas are low-grade neoplasms that are either pilocytic astrocytoma (WHO grade I) or diffuse astrocytoma (WHO grade II).[6] They have a relatively favorable prognosis. High-grade spinal astrocytomas, including anaplastic astrocytomas (WHO grade III) and intramedullary glioblastoma multiforme (WHO grade IV), are usually characterized by rapid progression[7,8] and short survival time.[9,10]

Therapeutic options for spinal astrocytoma include biopsy for histological diagnosis, decompressive surgery with subtotal resection (STR) or gross total resection (GTR) followed by adjuvant radiotherapy (RT) and/or chemotherapy.[9,11] Our current understanding of the epidemiology, prognosis, and optimal treatment of spinal astrocytoma is limited. The literature on spinal astrocytoma is confined to case reports or small institutional case series. Currently, there exists a paucity of studies analyzing adequate numbers of patients to draw conclusions that can guide patient management.

In this study, we performed a retrospective analysis on the prognostic factors, treatment, and outcome of patients with spinal astrocytoma using patients from four hospitals in the United States, China, and Italy. In addition, we performed an integrative analysis on individual patients pulled from published studies to make comparison with the results of our multi-institutional cohort analysis.

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