Localized incompletely resected standard risk rhabdomyosarcoma in children and adolescents: Results from the European Paediatric Soft Tissue Sarcoma Study Group RMS 2005 trial

Abstract

Background: The authors report the prospective evaluation of reduced dose alkylator chemotherapy combined with radiotherapy for European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) standard risk nonalveolar rhabdomyosarcoma (NA-RMS). Patients and Methods: Localized node negative Intergroup Rhabdomyosarcoma Study (IRS) II/III NA-RMS at favorable sites (subgroup C), <25 years old, received five cycles of ifosfamide, vincristine, and dactinomycin (IVA) chemotherapy (30 g/m2 ifosfamide) and four cycles of vincristine and dactinomycin (if receiving radiotherapy), or nine cycles of IVA (54 g/m2 ifosfamide) ± radiotherapy. Delayed primary tumor excision was considered for IRS III tumors. The primary end points were event-free survival (EFS) and overall survival (OS). Results: From October 2005 to December 2016, 359 evaluable patients were recruited: orbit, 164 (45.7%); head and neck nonparameningeal, 77 (21.4%); and genitourinary non–bladder/prostate, 118 (32.9%). EFS and OS were 77.4% (95% confidence interval [CI], 72.5–81.6) and 93.5% (95% CI, 90.1–95.8), respectively. Lower dose alkylator chemotherapy and radiotherapy achieved 5-year OS of 93.7% but the difference with higher dose alkylator chemotherapy +/- radiotherapy was not significant (p = 0.8003). Adjuvant radiotherapy improved EFS with 5-year estimates of 84.7% versus 65.2% for nonirradiated (p