Incidence and clinical course of radionecrosis in children with brain tumors

Abstract

Radionecrosis (RN) in children treated for brain tumors represents a potentially severe long-term complication. Its diagnosis is challenging, since magnetic resonance imaging (MRI) cannot clearly discriminate between RN and tumor recurrence. A retrospective single-center study was undertaken to describe the incidence and clinical course of RN in a cohort of 107children treated with external radiotherapy (RT) for various brain tumors between 1992 and 2012. During a median follow-up of 4.6years (range 0.29-20.1years), RN was implied by suspicious MRI findings in in 5children (4.7 %), 5-131months after RT. Suspicion was confirmed histologically (1patient) or substantiated by FDG positron-emission tomography (FDG-PET, 2patients) or by FDG-PET and MR spectroscopy (1patient). Before developing RN, all 5patients had received cytotoxic chemotherapy in addition to RT. In addition to standard treatment protocols, 2patients had received further chemotherapy for progression or relapse. Median radiation dose expressed as the biologically equivalent total dose applied in 2Gy fractions (EQD2) was 51.7Gy (range 51.0-60.0Gy). At RN onset, 4children presented with neurological symptoms. Treatment of RN included resection (n = 1), corticosteroids (n = 2) and a combination of corticosteroids, hyperbaric oxygen (HBO) and bevacizumab (n = 1). One patient with asymptomatic RN was not treated. Complete radiological regression of the lesions was observed in all patients. Clinical symptoms normalized in 3patients, whereas 2developed permanent severe neurological deficits. RN represents a severe long-term treatment complication in children with brain tumors. The spectrum of clinical presentation is wide; ranging from asymptomatic lesions to progressive neurological deterioration. FDG-PET and MR spectroscopy may be useful for distinguishing between RN and tumor recurrence. Treatment options in patients with symptomatic RN include conservative management (steroids, HBO, bevacizumab) and surgical resection.