3.1 I Patient characteristics
Of 81 consecutive children treated with proton radiation for brain tumors, at a single institution, 42 patients with ophthalmology exam records available, were included in the study. There was no significant difference between included and excluded patients in distribution by gender, age at start of radiation, tumor location (supratentorial or infratentorial), and radiation volume (CSI or IFRT or WVI) (Supplementary Tables 1a and 1b).
The demographic and clinical characteristics of the study patients are summarized in Table 1. There was nearly an equal distribution of patients by gender. The median age at start of radiation was 8.3 years and median follow-up from the end of radiation to the last ophthalmology exam, was 2.1 years. Most patients had supratentorial tumors (60%; 25/42 patients). Nearly a third of patients (31%; 13/42 patients) received CSI and most of the other patients received involved-field radiation therapy (IFRT). Median radiation dose to the lenses for the 13 patients who received CSI, was 22.68 (range 11.99 – 38.07) Gy RBE. Of the 29 patients with a radiation volume other than CSI (IFRT or WVI), only 5 patients received any radiation to their lenses, with a significantly lower dose ranging from 0.01 – 7.85 Gy RBE (values represent the mean dose to right and left lenses).
Post-radiation ocular complications occurred in 8 patients (19%; 8/42), all of whom received whole brain radiation as part of CSI (62%; 8/13). The characteristics of patients who developed ocular complications are summarized in Tables 2 and 3.