Patterns of failure using a conformal radiation therapy XXXX bed boost for @entity2946 .

@entity1 @entity5 @entity2946
PURPOSE: To assess the patterns of failure for @entity1 with @entity2946 receiving a conformal @entity5 bed boost rather than a boost to the entire posterior fossa. @entity1 AND METHODS: From 1994 to 2002, 32 consecutive @entity1 with newly diagnosed @entity2946 treated at Memorial Sloan-Kettering Cancer Center (New York, NY) received a conformal boost to the @entity5 bed in conjunction with craniospinal radiation therapy. Twenty-eight @entity1 also received chemotherapy. The median age was 9 years (range, 3 to 34 years), and the male to female ratio was 3:1. Twenty-seven @entity1 had standard-risk disease, and five @entity1 had high-risk disease. Craniospinal doses ranged from 23.4 to 39.6 Gy, and total @entity5 bed doses ranged from 54 to 59.4 Gy. RESULTS: With a median follow-up of 56 months, six @entity1 have relapsed; five relapsed outside of the posterior fossa, and one failed within the posterior fossa, outside of the high-dose boost volume. Five-year actuarial disease-free and overall survival rates were 84% and 85%, respectively. Freedom from posterior fossa failure was 100% and 86% at 5 and 10 years, respectively. Freedom from distant failure was 84% at 5 years, with a trend for improvement when full-dose craniospinal radiation (36 to 39.6 Gy) was used compared with a reduced dose (23.4 Gy) of radiation (100% v 63%, respectively; P =.06). No other predictive variables were identified. CONCLUSION: Conformal treatment to the @entity5 bed allows for significant sparing of critical structures. The posterior fossa failure rate in this series is similar to that reported when the entire posterior fossa is treated. This approach should be investigated further in a phase III trial.
