Necrosis in pontine gliomas: radiation induced or natural history?

Abstract

To determine whether the central necrotic lesions that develop in a large number of patients with pontine gliomas are secondary to radiation therapy, specifically high-dose (7,200-7,800 cGy) hyperfractionation radiation therapy, or are part of the biologic progression of this tumor. The authors analyzed neuroimaging studies of 31 consecutive patients with pontine-centered gliomas and assessed the time of onset of necrosis, the type and dose of radiation therapy administered, and the length of survival. Necrosis was present at diagnosis in eight of the 31 patients (26%). Time to appearance and total prevalence of central necrosis did not differ in the standard versus hyperfractionated therapy groups. The time between diagnosis and the appearance of necrosis correlated with length of survival (P = .005, Kendall correlation). In a substantial number of patients, central necrosis in pontine gliomas is not caused by radiation therapy but is an indication of an advanced tumor stage. Children with central necrosis at diagnosis have a significantly shorter median survival than do those without, regardless of the type of therapy administered.