Incidence, risks, and sequelae of posterior fossa syndrome in pediatric medulloblastoma.

Purpose: To investigate the incidence, risks, severity, and sequelae of posterior fossa syndrome (PFS) in children with medulloblastoma.

Methods And Materials: Between 1990 and 2007, 63 children with medulloblastoma at Emory University and Children's Healthcare of Atlanta were treated with craniectomy followed by radiation. Fifty-one patients were assigned to a standard-risk group, and 12 patients were assigned to a high-risk group. Five patients had <1.5-cm(2) residual tumor, 4 had >or=1.5-cm(2) residual tumor, and the remainder had no residual tumor. Eleven patients had disseminated disease. Patients received craniospinal irradiation at a typical dose of 23.4 Gy or 36 Gy for standard- or high-risk disease, respectively. The posterior fossa was given a total dose of 54 or 55.8 Gy. Nearly all patients received chemotherapy following cooperative group protocols.

Results: Median follow-up was 7 years. PFS developed in 18 patients (29%). On univariate analysis, brainstem invasion, midline tumor location, younger age, and the absence of radiographic residual tumor were found to be predictors of PFS; the last two variables remained significant on multivariate analysis. From 1990 to 2000 and from 2001 to 2007, the proportions of patients with no radiographic residual tumor were 77% and 94%, respectively. During the same eras, the proportions of patients with PFS were 17% and 39%. Only 4 patients had complete recovery at last follow-up.

Conclusions: The incidence of PFS increased in the latter study period and is proportional to more aggressive surgery. Children with midline tumors exhibiting brainstem invasion are at increased risk. With the increased incidence of PFS and the permanent morbidity in many patients, the risks and benefits of complete tumor removal in all patients need to be reexamined.