UKCCSG study of accelerated radiotherapy for pediatric brain stem gliomas

: Between 1991 and 1994, the United Kingdom Childhood Cancer Study Group (UKCCSG) conducted a multicenter study to assess the efficiency and tolerability of accelerated in children with a diagnosis of poor-prognosis brain stem glioma.

: Patients eligible for study were those aged 3–16 years with tumors arising in the pons. medulla, or midbrain, not previously treated with radiotherapy or chemotherapy. Histologic confirmation was not mandatory, but computed tomography or magnetic resonance imaging and clinical findings had to be typical, and patients were selected with short prediagnosis symptom history (< 3 months), cranial nerve palsies or long tract signs, and intrinsic diffuse lesions on scanning. The treatment dose was 48.6 Gy in 27 fractions, increased to 50.4 Gy in 28 fractions in January 1992, delivered twice daily (except weekends) with an interfraction interval of at least 8 h. Between January 1991 and July 1994, 28 available patients were recruited: 15 boys and 13 girls with ages ranging between 3 and 13 years (median 6).

: After treatment, neurologic improvement sustained for a period of at least 6 weeks without steroids was reported in 13 children (46%). On central review of postradiotherapy imaging, 50% of children showed evidence of partial response, but none exhibited a complete response. A further six patients (22%) had stable disease. The median survival time was 37 weeks (8.5 months); 1-year survival was 32%, and 2-year survival 11%. The pattern of relapse was local in all 26 patients who died of their disease; 1 patient had evidence of leptomeningeal seeding. Acute radiation morbidity was minimal, with only three patients (11%) exhibiting mild toxicity. No evidence of radiation-induced necrosis was found radiologically or histologically at postmortem. Ability to withdraw steroids following radiotherapy was the single most important prognostic variable in our study.

: The results of this study are comparable to previous outcomes of studies with conventional and hyperfractionated radiotherapy in poor-prognosis brain stem glioma. The fractionation regimen was shown to be tolerable with an acceptable morbidity profile. However, further research is required to improve the poor prognosis of these unfortunate children.