Surgical outcomes in diffuse leptomeningeal glioneuronal tumours: a systematic review and individual patient data meta-analysis.

OBJECTIVE

Diffuse leptomeningeal glioneuronal (DLGNT) tumours are rare entities whose tumour characteristics and surgical outcomes have eluded clarification. We present the first survival analysis to date.

METHODS

A systematic search of the Medline, EMBASE, SCOPUS, Google Scholar and Cochrane Database of Systematic Reviews was conducted. Overall survival (OS) and progression free survival (PFS) were selected as primary outcomes. Individual variables were age, sex, presence of hydrocephalus, extent of resection, and receipt of postoperative adjuvant therapy. Standard Kaplan-Meier survival analysis was performed with stratified cohorts plotted and outcomes compared by the log-rank test.

RESULTS

87 histologically-proven cases of DLGNT from 18 studies were included. Mean OS was 39.1 months whilst mean PFS was 27.8 months. The 5-year OS and PFS was 81.8% (95% CI, 72.5-92.3%) and 48.6% (95% CI, 36.9-64.0%) respectively. Hydrocephalus at time of presentation results in poorer OS (p = 0.026), whilst an infratentorial location leads to reduced PFS (p < 0.05). Extent of resection did not independently predict OS (p = 0.85) or PFS (p = 0.72). Similarly, postoperative adjuvant therapy appeared to have minimal effect on OS (p = 0.24) or PFS (p = 0.15) outcomes.

CONCLUSIONS

Diffuse leptomeningeal glioneuronal tumours are infiltrative in nature and commonly involve the spine. It is crucial to distinguish this entity from other mimics such as leptomeningeal gliomatosis which has a poorer prognosis. Surgical resection remains the mainstay of treatment if there is a dominant parenchymal component, followed by adjuvant chemotherapy and craniospinal irradiation if leptomeningeal disease is widespread. Emerging molecular characteristics such as methylation status may guide future management.