Prognostic factors for progression of childhood optic pathway glioma: a systematic review.

A systematic literature review was carried out to evaluate best existing evidence on prognostic factors for progression of childhood optic pathway glioma. Databases were searched for relevant articles and articles selected independently by two authors. Information about study design, population, treatment, outcome and prognostic analysis were abstracted and the quality of each article was assessed. A total of 23 articles met the inclusion criteria. Many studies had important methodological limitations, regarding external and internal validity. Eleven studies evaluated possible prognostic factors in a multivariate analysis. Three high-quality studies indicated age<1 year as an independent prognostic factor for a worse progression-free survival. Three studies with multivariate analysis, including one high-quality study, found that children with neurofibromatosis type 1 (NF-1) have a better progression-free survival than those without NF-1. Two studies with multivariate analysis found tumour site to be a prognostic factor, both with some methodological limitations. In conclusion, this systematic review demonstrates that only a few of the prognostic factors proposed have been proven to be clinically relevant. Age<1 year is a clear and independent prognostic factor for progression-free survival. Other prognostic factors, such as NF-1, tumour site and others, are suggested, but are still without solid evidence and need further high-quality studies to be clearly proven.