Ventricular size determination and management of ventriculomegaly and hydrocephalus in patients with diffuse intrinsic pontine glioma: an institutional experience
Authors: Fonseca Adriana , Solano Palma , Ramaswamy Vijay , Tabori Uri , Huang Annie , Drake James M. , Tsang Derek S. , Laperriere Normand , Bartels Ute , Kulkarni Abhaya V. , Bouffet Eric 
Published: March 2021

OBJECTIVE
There is no consensus on the optimal clinical management of ventriculomegaly and hydrocephalus in patients with diffuse intrinsic pontine glioma (DIPG). To date, the impact on survival in patients with ventriculomegaly and CSF diversion for hydrocephalus in this population remains to be elucidated. Herein, the authors describe their institutional experience.

METHODS
Patients diagnosed with DIPG and treated with up-front radiation therapy (RT) at The Hospital for Sick Children between 2000 and 2019 were identified. Images at diagnosis and progression were used to determine the frontal/occipital horn ratio (FOR) as a method to measure ventricular size. Patients with ventriculomegaly (FOR ≥ 0.36) were stratified according to the presence of symptoms and categorized as follows: 1) asymptomatic ventriculomegaly and 2) symptomatic hydrocephalus. For patients with ventriculomegaly who did not require CSF diversion, post-RT imaging was also evaluated to assess changes in the FOR after RT. Proportional hazards analyses were used to identify clinical and treatment factors correlated with survival. The Kaplan-Meier method was used to perform survival estimates, and the log-rank method was used to identify survival differences between groups.

RESULTS
Eighty-two patients met the inclusion criteria. At diagnosis, 28% (n = 23) of patients presented with ventriculomegaly, including 8 patients who had symptomatic hydrocephalus and underwent CSF diversion. A ventriculoperitoneal shunt was placed in the majority of patients (6/8). Fifteen asymptomatic patients were managed without CSF diversion. Six patients had resolution of ventriculomegaly after RT. Of 66 patients with imaging at the time of progression, 36 (55%) had ventriculomegaly, and 9 of them required CSF diversion. The presence of ventriculomegaly at diagnosis did not correlate with survival on univariate analysis. However, patients with symptomatic hydrocephalus at the time of progression who underwent CSF diversion had a survival advantage (p = 0.0340) when compared to patients with ventriculomegaly managed with conservative approaches.

CONCLUSIONS
Although ventriculomegaly can be present in up to 55% of patients with DIPG, the majority of patients present with asymptomatic ventriculomegaly and do not require surgical interventions. In some cases ventriculomegaly improved after medical management with steroids and RT. CSF diversion for hydrocephalus at the time of diagnosis does not impact survival. In contrast, our results suggest a survival advantage in patients who undergo CSF diversion for hydrocephalus at the time of progression, albeit that advantage is likely to be confounded by biological and individual patient factors. Further research in this area is needed to understand the best timing and type of interventions in this population.