MEDULLOBLASTOMA IN ADULTS

Purpose: To assess the outcome and prognostic factors for adult patien ts with medulloblastoma managed by postoperative radiotherapy between 1958 and 1988 at the Princess Margaret Hospital. Methods and Materials : A retrospective review was undertaken of 48 patients age 16 years or older who received radiotherapy for medulloblastoma. The median age a t diagnosis was 25 years, with 36 male and 12 female patients. Sixteen tumors were confined to midline structures, and 32 were localized to a cerebellar hemisphere or involved midline and lateral structures. Th e desmoplastic variant was reported in 12 cases. Complete macroscopic removal was achieved in 22 patients, subtotal removal in 23, and biops y only in 3. Forty-six patients received craniospinal radiation and 2 patients received local irradiation only. Results: Median overall surv ival was 7.9 years, and 5- and 10-year overall survival was 62% and 41 %, respectively. Significant factors for disease-free survival were M stage (MO vs. M1-4, p = 0.0005), functional state at the time of radio therapy (1-2 vs. 3-5, p = 0.005), and the absence or presence of hydro cephalus preoperatively (p = 0.02). Twenty-four patients developed rec urrent disease, with 14 relapsing first in the posterior fossa. Subtot al removal of tumor (p = 0.04) was the only factor predictive of poste rior fossa relapse. Conclusions: Patients with disease outside the pos terior fossa at diagnosis, symptomatic patients (neurologic functional state 3-5) at the time of radiotherapy, and those who present with hy drocephalus have poorer disease-free survival. Gross total resection i mproved posterior fossa control.