Supratentorial pilocytic astrocytomas. A clinicopathologic, prognostic, and flow cytometric study of 51 patients.

BACKGROUND

Supratentorial pilocytic astrocytomas are uncommon tumors, the prognosis and management of which have been controversial.

METHODS

The authors retrospectively studied the clinical and pathologic aspects of 51 patients with supratentorial pilocytic astrocytomas, with particular reference to their response to treatment.

RESULTS

The study group consisted of 25 male and 26 female patients (median age, 15 years). The extent of surgical removal was gross total or radical subtotal in 16 patients and subtotal removal or biopsy in 35. At a median follow-up of 14.9 years, 41 patients were alive. Overall survival was 82% at 10 and 20 years; 89% of surviving patients were fully active. Survival at 10 years was 100% for the 16 patients who underwent gross total or radical subtotal removal and 74% for the 35 who had subtotal tumor removal or biopsy. No association was found between pathologic features such as histologic grade or flow cytometric characteristics and patient survival.

CONCLUSIONS

Supratentorial pilocytic astrocytomas behave differently from low-grade astrocytomas of the diffuse or fibrillary type in that they have a favorable prognosis. Radiation therapy appears not to be needed for patients undergoing gross total removal. In patients undergoing subtotal resection, close follow-up with additional surgery or radiation therapy at the time of tumor progression is recommended. Patients who have biopsy only should receive radiation therapy. Histologic grading and flow cytometric analysis add little to clinical decision making with regard to patients with pilocytic astrocytoma.