A 10 year retrospective study of surgical outcomes of adult intracranial pilocytic astrocytoma.

Pilocytic astrocytomas (PA) are benign neoplasms commonly located in the cerebellum with a peak incidence in the first two decades of life. PA occurrence in adults is rare and very little information is available in the literature about tumour characteristics in this population. This study retrospectively identified 20 adults with PA. The characteristics of the tumour, treatment modalities and patient outcomes are discussed, as well as identifying factors that may be associated with worse prognosis. The mean age at diagnosis was 27 years. The majority of PA were located in the posterior fossa. Other tumour locations included the cerebral hemispheres, brainstem, tectal plate and optochiasmatic region (optic chiasm, hypothalamus and third ventricle). All patients in this study underwent surgery, two received adjuvant chemotherapy and one received adjuvant radiotherapy. Tumour recurrence occurred in six patients and two eventually died from the disease. When achieved, complete tumour resection was found to be curative. Tumour location affects extent of surgical resection; tumours in inaccessible locations were associated with higher rates of recurrence. Overall survival and progression free survival rates were 87% and 60% respectively. The degree of surgical resection and tumour location were found to affect prognosis. Unfavourable outcomes were observed in these adults with PA compared to those expected for a younger population, suggesting a possible association between age and outcome.