Should adult medulloblastoma patients at low risk receive adjuvant chemotherapy? Long-term results of a prospective study

2018 Background: Due to the rarity of medulloblastoma (MB) in adults, the few studies available on this condition are retrospective, and the follow-up tends to be short. Furthermore, the different therapeutic strategies used in these patients makes it difficult to assess survival rates and prognostic factors. Methods: Between January 1989 and February 2001, a prospective phase II trial was performed to evaluate the efficacy of treatment for adults with medulloblastoma. Patients were completely staged with a neuroradiological examination of the brain and neuraxis and by CSF cytology, according to Chang’s staging system. Low risk patients received radiotherapy alone, while high risk patients were given 2 cycles of upfront chemotherapy followed by radiotherapy and adjuvant chemotherapy. The results of the preliminary analysis of this study at a median follow-up of 3.7 years are reported elsewhere. The present papers reports on the long- term results of the same trial. Results: After a median follow up of 7.6 years, among a total of 36 enrolled adults with medulloblastoma, overall progression free survival (PFS) and overall survival (OS) at 5 years were 72% (range 59% to 84%) and 75% (62% to 91%), respectively. No difference was found between low and high risk patients in terms of PFS and OS at 5 years: in low-risk patients the 5-year PFS was 80% (range, 59–100%) and the 5-year OS, 80% (range, 58 - 100%); in high-risk patients the 5-year PFS was 69% (range, 54 -89%) and the 5-year OS, 73% (range, 58 - 92%). Conclusions: A long-term follow-up is essential to evaluate the real impact of treatments in adult patients with MB. Since there is no significant difference between low-risk and high-risk patients for PFS and OS, the use of chemotherapy is also questionable in low-risk patients. No significant financial relationships to disclose.