Medulloblastoma in adulthood is rare. Knowledge is limited, and the efficacy and toxicity of chemotherapy--especially in nonmetastatic disease--is still elusive.

Seventy adults aged ≥21 years (median age: 28.5 years) with nonmetastatic medulloblastoma were followed as observational patients within the prospective paediatric multicentre trial HIT 2000. Treatment consisted of radiotherapy (35.2 Gy to the craniospinal axis and a boost to 55.2 Gy to the posterior fossa) followed in most patients by maintenance chemotherapy (lomustine (CCNU), vincristine and cisplatin, n=49).

The implementation of maintenance chemotherapy was feasible. Peripheral neuropathy (74%) and haematotoxicity (55%) during maintenance chemotherapy appear to be more common in adults than in children. At a median follow-up of 3.7 years, the 4-year event-free survival (EFS) and overall survival (OS) rates±standard error (SE) were 68%±7% and 89%±5%. Patients with desmoplastic medulloblastoma and lateral tumour location (n=19) had a lower EFS compared to patients with centrally located desmoplastic tumours (n=10) (p=0.011). Absence of residual postoperative tumour (n=40) was associated to a lower rate of progression/relapse compared to present (n=11) or unknown (n=12) residual tumour status (p=0.006). Lateral tumour location and unknown residual tumour status were independent negative prognostic factors.

Maintenance chemotherapy is applicable in adults with nonmetastatic medulloblastoma. Histological subtype and tumour location were newly identified risk factors in this age-group, and should be further analysed in prospective trials.