Volumetric considerations in radiotherapy for pediatric XXXX .

@entity980 @entity1 @entity5
PURPOSE: To assess the influence of radiation volume on outcome in pediatric @entity980 ( @entity980 ). METHODS AND MATERIALS: Thirty @entity1 ranging in age from 2 to 18 years (median 6) with PM-RMS were treated at the Hospital of the University of Pennsylvania and the @entity1 's Hospital of Philadelphia between August 1988 and December 1999. The histologic subtypes included embryonal (n = 26), alveolar (n = 3), and undifferentiated (n = 1). Twenty-seven @entity1 had Group III and three had Group IV disease. Twenty-seven @entity1 underwent biopsy only and three subtotal resection. All @entity1 were treated with multiple-agent chemotherapy and external beam radiotherapy. In 8 @entity1 , all of whom had @entity5 extension, the @entity5 and whole brain were treated as the initial volume. In the remaining @entity1 , most of those treated before 1992 were treated to the prechemotherapy (CMT) @entity5 volume for the entire treatment up to the total dose, which ranged from 45 to 59.4 Gy (median dose 57.9). In contrast, @entity1 treated after 1992 generally received radiation initially to the pre-CMT volume (30.6-40 Gy; median dose 36) followed by a conedown to the post-CMT volume to a final dose of 41.4-55.2 Gy (median 50.4). RESULTS: With a median follow-up of 6.2 years (range 2.1-13.3), the actuarial 5-year overall survival, progression-free survival, and local control rate for the entire group was 82%, 76%, and 76%, respectively. Seven failures and five deaths have been documented. In univariate analysis, histologic type, @entity5 size, and age at diagnosis were found to be predictive of overall survival and local control. No statistically significant difference in overall survival or local control was seen between @entity1 who received a conedown to the post-CMT volume (n = 13) and @entity1 in whom the pre-CMT volume was included for the entire treatment (n = 9). CONCLUSION: Radiotherapy delivered to @entity1 with PM-RMS using a shrinking field technique with a post-CMT volume boost was effective and appears to give results comparable to those of @entity1 in whom the pre-CMT volume was treated for the entire course. The use of such tailored treatment fields is likely to lead to fewer late effects and warrants further investigation.
