Patterns of Failure in Patients With Adult Medulloblastoma Presenting Without Extraneural Metastasis

The objective of this study is to evaluate long-term outcomes, specifically patterns of tumor recurrence, in patients with adult medulloblastoma treated with radiotherapy.

We recorded outcomes of 28 (median age, 25 y) patients 18 years old or above with M0 to M3 medulloblastoma treated between 1971 and 2012. Among them, 61% had standard-risk disease. All received craniospinal irradiation with a posterior fossa boost. Median dose to the craniospinal axis was 36 Gy. Median total dose to the primary site was 55.9 Gy and 46% received chemotherapy.

Median follow-up among survivors was 14.2 years. At 5 and 10 years, local control was 80% and 73%, overall survival was 71% and 59%, cause-specific survival was 71% and 63%, and freedom from progression was 68% and 59%. Tumors recurred in 11 patients (39%); median time to recurrence was 2.4 years, and 82% of recurrences developed in patients with standard-risk disease. Of the recurrences, 55% involved the primary site; 36% were bone metastases without neural axis recurrence. There were no isolated recurrences in the spinal canal or ventricular system outside of the posterior fossa.

The primary site is the main site of medulloblastoma recurrence, with isolated bone metastases more common in adults than children. Our results prompt us to consider 4 modifications to our treatment approach with adults who present with medulloblastoma: (1) initial staging to include PET or bone scan; (2) radiotherapy dose to the primary site of 59.4 Gy; (3) chemotherapy during and/or following radiotherapy in medically fit patients; (4) follow-up to include PET or bone scan twice a year for 3 years.