Astrocytomas of the cerebellum. A comparative clinicopathologic study of pilocytic and diffuse astrocytomas.

BACKGROUND

The majority of patients with astrocytomas of the cerebellum have an excellent prognosis; however, a small percentage of patients continue to do poorly. To clarify the clinical, pathologic, and treatment characteristics that determine prognosis and therapeutic recommendations, a large group of patients with astrocytic tumors of the cerebellum was reviewed and analyzed.

METHODS

A clinicopathologic analysis was performed of all patients undergoing initial operation for astrocytomas in the cerebellum between 1960 and 1984. Of the 132 patients, 105 patients had pilocytic astrocytomas and 27 had diffuse astrocytomas.

RESULTS

Multivariate analysis revealed that the division of pilocytic and diffuse histologic type was the most significant prognostic factor influencing survival. The 5-year, 10-year, and 20-year survival rates were 85%, 81%, and 79%, respectively, for patients with pilocytic astrocytomas and 7%, 7%, and 7%, respectively, for patients with diffuse astrocytomas (P < 0.001). Pilocytic astrocytomas occurred in a younger age group and were more commonly cystic and completely resected.

CONCLUSIONS

Astrocytomas of the cerebellum can be divided into two principal groups, the pilocytic and the diffuse astrocytomas, each of which has distinct clinical, pathologic, and prognostic characteristics.