Encouraging Early Outcomes of Treatment With Arsenic Trioxide Combined With Chemotherapy for Alveolar Rhabdomyosarcoma in Children: 4 Case Reports

BACKGROUND: Alveolar rhabdomyosarcoma (ARMS) is a subtype of rhabdomyosarcoma characterized by its aggressive behavior and poor prognosis, highlighting the need for novel treatment options. Arsenic trioxide (ATO) has been shown to specifically inhibit tumor growth and the metastasis of ARMS in vitro by acting on the hedgehog pathway. Here we report on a pilot clinical study to evaluate the activity of an ATO-combined chemotherapy approach for the treatment of ARMS patients. METHODS: We designed a therapeutic schedule of an ATO-combined chemotherapy, incorporating comprehensive management according to the Intergroup Rhabdomyosarcoma Study Group protocol. ATO was administered at 0.16 mg/kg per day over 8 h via an IV for 10 days combined with a chemotherapeutic regimen of vincristine, actinomycin, and cyclophosphamide (VAC regimen) on the third day, which was repeated every 21 days. A total of eight cycles of ATO-combined chemotherapy were applied throughout the entire scheme. RESULTS: A total of three refractory/recurrent and one untreated ARMS patient, three male and one female, with a median age of 5.8 years (range, 5.1 to 12.5 years), were enrolled in the present study. All patients were sensitive to combined chemotherapy with ATO and achieved partial or complete remission during treatment. Except for reversible gastrointestinal reaction and myelosuppression, no other adverse events were observed during the process of treatment. CONCLUSIONS: The combined chemotherapy of ATO and the VAC regimen exhibited beneficial activities against ARMS in pediatrics and was well tolerated, but prospective large-scale clinical trials are warranted to determine the long-term efficacy, optimal courses, and late toxicity in this population.