Low grade astrocytomas in the West of Scotland 1987-96: treatment, outcome, and cognitive functioning

Background-Low grade astrocytomas are among the most common central nervous system tumours in children. Aims-To identify risk factors for the development of persistent intellectual handicap. Methods-The notes of 30 children with histologically proven low grade astrocytoma who presented during the period 1987-96 were reviewed. Thirteen of these children who were diagnosed with intracranial tumours between 1992 and 1996 underwent cognitive assessment one year after the completion of treatment. Results-Low grade astrocytomas were found in the cerebellum (59%), thalamus (17%), cerebral hemispheres (10%), and the cervical spinal cord (9%). Where possible all patients were treated with gross total resection of the tumour. Symptomatic children with tumours judged to be inoperable underwent biopsy followed by radiotherapy (13%). Three patients developed progressive disease following surgery and underwent repeat surgery and radiotherapy. Survival at a median follow up of 75 months (range 30-131) is 97%. At one year after the completion of treatment persisting cognitive impairment was common. The strongest predictor of IQ scores was the duration of symptoms of increased intracranial pressure preoperatively. Conclusions-Although the overall survival rate of children with low grade astrocytoma is excellent, significant long term disability occurs. Early diagnosis is essential to reduce postoperative cognitive morbidity.