Modified SMILE (mSMILE) is active in the treatment of pediatric Epstein-Barr virus-associated natural killer/T-cell lymphoma: a single center experience, case series.

Background: The Epstein-Barr virus-associated natural killer (NK) and T-cell lymphoma (EBV + NK/T cell lymphoma) is a severe illness mainly affecting children and young adults, often resulting in a poor prognosis. To date, there is no consensus on an established treatment strategy. This study aims to evaluate the efficacy and safety of the mSMILE (modified steroid, methotrexate, ifosfamide, L-asparaginase, and etoposide) chemotherapy regimen in treating EBV+ NK/T-cell lymphoma and to provide insights into potential treatment outcomes.

Methods: In this study, we conducted a retrospective analysis of the clinical data and treatment outcomes for patients with EBV + NK/T cell lymphoma treated at Children's Hospital of Nanjing Medical University between July 2017 and January 2022. These patients received at least two cycles of the mSMILE chemotherapy, in which a single dose of pegaspargase was substituted for 7 doses of L-asparaginase per cycle.

Results: Eight patients were included in the study: one with extranodal NK/T-cell lymphoma, one with primary nodal NK/T-cell lymphoma, and six with Systemic EBV+ NK/T cell lymphoma of childhood. The results showed that five patients achieved complete remission, two achieved partial remission, and one showed progressive disease, resulting in a complete remission rate of 62.5% and an overall response rate of 87.5%. The 3-year overall survival (OS) and event-free survival (EFS) rates were 87.5% and 75%, respectively. The most common adverse reactions associated with chemotherapy were hematologic toxicities of stages III to IV. Nonhematologic adverse reactions mainly included impaired liver function, infections, and oral mucositis, which were resolved with aggressive anti-infective therapy.

Conclusions: Based on our clinical experience, the mSMILE appears to be a safe and effective treatment option for EBV + NK/T-cell lymphoma, meriting further investigation in late-phase clinical trials.