A Model to Assess Time to Treatment in Children with Optic Pathway Gliomas

Abstract

Evangelos Drimtzias, Polychronis Economou, Kevin Falzon, Susan Picton and Ian Simmons

The objective of the present study is to identify factors that may be of prognostic value to predict the need for chemotherapy in paediatric patients with optic pathway gliomas (OPGs) and to propose a screening protocol where the hazard rate for the time from diagnosis to initiation of therapy can be estimated in each patient individually. A search in the national Low Grade Glioma (LGG) database was performed allowing identification of 93 children with OPGs from 21 participating centers in the UK. A variable selection procedure based on stepwise regression was applied to identify the significant risk factors that are of prognostic value to predict the need for treatment. A Receiver Operating Characteristic (ROC) curve was used to determine the optimal threshold for classifying the patients. The influence of the available risk factors on the time from diagnosis to initiation of therapy was assessed by a Cox proportional hazards model. Children without Neurofibromatosis type 1 (NF 1) were more likely to have tumour involvement of the most posterior visual pathway. Children with posterior tumour involvement and subjects with poor visual acuity (VA) and younger age at diagnosis were found to be the groups with the highest risk of receiving treatment. Three diagnostic groups (high, moderate, and low risk) were defined with respect to their estimated probability of receiving treatment. Individualized hazard function plots and point estimations for the probability of the need of treatment may modify the frequency and duration of follow-up evaluations in OPG patients.

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