Shorter-duration therapy using vincristine, dactinomycin, and lower-dose cyclophosphamide with or without radiotherapy for patients with newly diagnosed low-risk rhabdomyosarcoma: A report from the soft tissue sarcoma committee of the Children's Oncology Group

Results: With a median follow-up of 4. 3 years, we observed 35 failures among 271 eligible patients versus 48. 4 expected failures, calculated using a fixed outcome based on the FFS expected for similar patients treated on the IRSG D9602 protocol. The estimated 3-year FFS rate was 89% (95% CI, 85% to 92%), and the overall survival rate was 98% (95% CI, 95% to 99%). Patients with paratesticular tumors had the most favorable outcome. Three-year cumulative incidence rates for any local, regional, or distant failures were 7. 6%, 1. 5%, and 3. 4%, respectively.

Conclusion: Shorter-duration therapy that included lower-dose cyclophosphamide and RT did not compromise FFS for patients with subset-one low-risk ERMS.

Purpose: Intergroup Rhabdomyosarcoma Study Group (IRSG) studies III and IV showed improved failurefree survival (FFS) rates with vincristine, dactinomycin, and cyclophosphamide (VAC; total cumulative cyclophosphamide dose, 26. 4 g/m2) compared with vincristine and dactinomycin (VA) for patients with subset-one low-risk embryonal rhabdomyosarcoma (ERMS; stage 1/2 group I/II ERMS or stage 1 group III orbit ERMS). The objective of Children's Oncology Group ARST0331 was to reduce the length of therapy without compromising FFS for this subset of low-risk patients by using VA in combination with lower-dose cyclophosphamide (total cumulative dose, 4. 8 g/m2) plus radiotherapy (RT).

Patients and Methods: This noninferiority prospective clinical trial enrolled newly diagnosed patients with subset-one clinical features. Therapy included four cycles of VAC followed by four cycles of VA over 22 weeks. Patients with microscopic or gross residual disease at study entry received RT.