Patients with Embryonal Rhabdomyosarcoma Completely Resected at Diagnosis: An International Analysis

The survival of patients with localized embryonal rhabdomyosarcoma (RMS) completely resected at diagnosis is above 90%. Most of them have paratesticular, uterus, or vaginal RMS, limiting specific analyses on RMS localized in other anatomic regions. To define the outcome for completely resected embryonal RMS at sites other than paratesticular/uterine/vaginal primary sites, we conducted this international study.Methods: We identified 113 patients, aged 0-18 years, enrolled from 1/1995 to 12/2016 in Children’s Oncology Group (COG) (64 patients) and European protocols (49). Genito-urinary non-bladder/prostate RMS were excluded. The recommended chemotherapy was VA (vincristine, actinomycin-D) for 24 weeks or IVA (ifosfamide plus VA) in the European protocols and VA for 48 weeks or VAC (VA plus cyclophosphamide) in the COG protocols.Results: The most common primary sites were non-parameningeal head and neck (40.7%), other (23.9%) and extremities (20.4%). In the COG studies, 42% of patients received VA and 58% VAC. In Europe 53% received VA and 47% IVA.With a median follow-up of 97.5 months the 5-year progression free and overall survival was 80.0% (71.2-86.4) and 92.5% (85.6-96.2), respectively, without significant differences between chemotherapy regimens. Tumor size ( < or > 5 cm) significantly influenced overall survival: 96.2% (88.6-98.8) vs. 80.6% (59.5-91.4), respectively (p 0.01).Conclusion: Survival of patients with non alveolar RMS completely resected at diagnosis is good among tumors arising from non-paratesticular/uterine/vaginal sites, and patients may be treated successfully with low intensity chemotherapy. To reduce the burden of treatment VA for 24 weeks may be considered in children with tumors < 5 cm.