Medulloblastoma in adults: treatment results and prognostic factors

PURPOSE: To investigate the treatment outcome and prognostic factors of adult medulloblastoma patients who received postoperative craniospinal irradiation (RT). METHODS AND MATERIALS: Between 1983 and 2000, 30 adult patients (17 men and 13 women, age >or=16 years, median 27, range 16-45) underwent postoperative RT. The median duration of symptoms was 2 months (range 1-9). The tumor location was lateral in 16 (53%). A desmoplastic variant was seen in 12 (40%). Tumor resection was complete in 20 (67%) and incomplete in 10 (33%). All patients received craniospinal RT. The median dose to the whole brain was 40 Gy (range 36-51), to the posterior fossa 54 Gy (range 49-56), and to the spinal axis 36 Gy (range 24-40). The median interval between surgery and the start of RT was 31 days (range 12-69), and the median duration of RT was 45 days (range 34-89). Ten patients (33%) received adjuvant chemotherapy. The median follow-up was 51 months (range 5-215). RESULTS: The 5- and 8-year overall survival and disease-free survival rates were 65% and 51% and 63% and 50%, respectively. Twelve patients (40%) developed relapse, with a median follow-up of 51 months. The posterior fossa was the most common site of relapse (6 patients). The median time to relapse was 26 months (range 4-78). Fifty percent of the relapses occurred after 2 years, 17% after 5 years. In univariate analysis, M stage and the interval between surgery and the start of RT were significant prognostic factors for disease-free survival. At 5 years, 70% of M0 patients were estimated to be disease-free, but none of the 3 M3 patients reached 5 years without recurrence (p = 0.0002). The 5-year disease-free survival rate for the patients whose interval between surgery and the start of RT was 6 weeks was 0%, 85%, and 75%, respectively (p = 0.002). The 5-year posterior fossa control rate for patients who received >or=54 Gy or