Introduction
Neuroblastoma is the most common extracranial solid tumor in children. The advent of multidisciplinary treatment approach (including chemotherapy, surgery, radiotherapy, and high-dose chemotherapy with autologous peripheral blood stem cell rescue) has helped improve the prognosis of patients with neuroblastoma1. However, patients with refractory or relapsed neuroblastoma have unfavorable prognosis2,3 despite the development of various salvage therapies, including irinotecan alone4, irinotecan with temozolomide5, ICE (ifosfamide, carboplatin, and etoposide)6, and TOPO-CY (topotecan and cyclophosphamide)7 regimens. Therefore, development of new chemotherapy regimens for these patients is a key imperative.
A study reported the outcomes of IRinotecan, Etoposide, and Carboplatin (IREC) in five patients with refractory or relapsed neuroblastoma; one of the patients achieved complete response8. No further studies have investigated the outcomes of IREC regimen in a larger cohort. Irinotecan exerts a strong anti-tumor effect by inhibiting the action of type I topoisomerase9. Genetic polymorphisms in UGT1A1 are known to be associated with the development of severe side effects of irinotecan, such as diarrhea and leucopenia10. In this study, we investigated the outcomes of IREC therapy in 43 patients with refractory or relapsed neuroblastoma; in addition, we assessed the impact of UGT1A1 gene polymorphisms on treatment response and toxicity.