Reirradiation of recurrent medulloblastoma: does clinical benefit outweigh risk for toxicity?

BACKGROUND Patients with recurrent medulloblastoma (MB) have a dismal prognosis. There has been a reluctance to use radiation in the salvage therapy regimens for these patients because of concerns about toxicity and unknown efficacy. Comparing survival outcomes and toxicities in relapsed patients treated with and without radiation may help to define its role. METHODS A retrospective review was conducted that included 38 patients with recurrent MB treated with similar risk-adapted therapy at initial diagnosis; reirradiation was a component of salvage therapy in 14. Overall survival (OS) and toxicity were evaluated according to the use of radiation, prior risk stratification, and other factors. RESULTS For relapsed standard-risk patients, the use of additional irradiation resulted in a statistically significant improvement in OS from initial diagnosis (P = .036), with 5- and 10-year OS rates of 55% ± 14% and 33% ± 16% versus 46% ± 14% and 0% for reirradiated patients versus others, respectively. Similar improvement was observed in high-risk patients (P = .003). There was an association between the use of additional irradiation and an increased rate of necrosis as determined by neuroimaging (P = .0468). CONCLUSIONS The use of irradiation as a component of salvage therapy for relapsed MB may prolong survival. The benefit appears to be greatest for relapsed standard-risk patients.