Abstract
The outcomes and neurologic status of patients after PBT have been incompletely characterized, although radiographic changes have been described. The neurologic status of 29 consecutive children treated with PBT (a median of 44 months of age, range 17mo-13yrs) with PFTs (16 embryonal, 9 ependymoma, and 4 gliomas) was retrospectively assessed, and correlated to neuroradiographic findings. Median RT dose was 54GyRBE (range, 50.4-59.4GyRBE). Twenty-five of 29 patients (86%) had evidence of PBT-associated neuroradiographic change. At initial detection of neuroradiographic change, which occurred at a median of 4 months after PBT (range 1-12mo), 10 patients were symptomatic, including new or worsening ataxia (n=6), hemiparesis (n=4), and/or lower brainstem dysfunction (n=7). Four asymptomatic patients became symptomatic over the ensuing 6 months, including 2 who developed severe lower brainstem dysfunction and ataxia/hemiparesis. Eight of 15 symptomatic patients worsened during the year following initial radiographic change, including 3 who died of radiation-induced autopsy-proven brainstem injury; 4 patients improved but remained impaired, 1 was stable, and 2 returned to baseline. MR changes of all patients were scored by a neuroradiologist blinded to clinical status, on a novel neuroradiographic- damage scale (0 to 27) based on extent and location of signal abnormality, diffusion restriction, enhancement, and hemorrhage. Radiation change ranged between 0 and 18, with higher scores associated with poorer neurological outcome. Neurologic changes can occur after PBT for PFTs, dysfunction may occur early, can be progressive and fatal, and may result in ongoing neurologic dysfunction at least 1 year after initial radiographic detection.