Extranodal natural killer/T-cell lymphoma from skin or soft tissue: suggestion of treatment from multinational retrospective analysis

Clinical features and outcomes of extranodal natural killer/T-cell lymphoma (ENKL) arising from extranasal sites are not fully understood. The purpose of this study was to study the prognosis and treatment outcome of skin/soft tissue primary ENKL. This multicenter retrospective study included 48 patients with skin/soft tissue primary ENKL diagnosed from 1993 to 2010. Patients with Ann Arbor stage I, T1-2N0M0 by International Society for Cutaneous Lymphomas-European Organization of Research and Treatment of Cancer TNM (tumour-node-metastasis) stage, International prognostic index score of 0-1, and a Korean prognostic index (KPI) score of 0-1 were associated with better survival. Four of five patients with T1-2N0M0 disease achieved complete response with radiation alone. In disseminated disease, only 6 of 13 patients responded to anthracycline-containing chemotherapy, and all the two patients receiving SMILE showed response. In conclusion, we identified the prognostic value of KPI, and we suggest a treatment recommendation according to the TNM (tumour-node-metastasis) stage. Radiotherapy with/without chemotherapy seemed to be optimal in localized disease. In advanced stages, a more aggressive treatment regimen with newer agents should be sought.