Results From the IRS IV Randomized Trial of Hyperfractionated Radiation in Children with Rhabdomyosarcoma

Joel W. Goldwein, MD
OncoLink co-Editor-In-Chief
Last Modified: October 24, 2000

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Presenter: S. S. Donaldson, MD
Affiliation: The Intergroup Rhabdomyosarcoma Study


Background:

  • Hyperfractionated radiation therapy (HFRT) has the theoretical potential for improving efficacy without producing more late effects of children with rhabdomyosarcoma (RMS).

  • This analysis of the IRS experience in treating rhabdomyosarcomas with HFRT is the first phase III randomized trial of this therapy reported for children


Materials and Methods:

  • Children with Group III (gross residual tumor) rhabdomyosarcoma were randomized to receive either 50.4 Gy standard RT or 59.4 Gy in 1.1 Gy BID fractions HFRT, both beginning about week 9 post-resection and after initial chemotherapy

  • The dose of HFRT was predicted (based on alpha/beta model) to increase effective tumor dose by 10% without increasing the late toxicity


Results:

  • 450 children were analyzed, 251 of whom received HFRT and 239 of whom received conventional RT

  • Compliance to radiation protocol was only 57% for patients <= 5 years of age, and 88% for older patients

  • Five year actuarial survival was 75%, and relapse-free survival was 70%

  • There was no significant difference in survival for the 2 groups

  • When analyzed by intent to treat, there was no significant difference on freedom-from-relapse for the 2 groups

  • Local failure rate was 12% for the conventional RT patients and 15% for the HFRT patients; this was not significantly different

  • Grade III and IV toxicity was 86% in the conventional RT group and 89% in the HFRT group; also not significantly different


Authors' Conclusions

  • HFRT as described above does not improve tumor control in these patients


Clinical/Scientific Implications:

  • Conventional RT remains the standard of care for children with Group III rhabdomyosarcoma