Treatment of refractory/relapsed extranodal NK/T cell lymphoma with decitabine plus anti-PD-1: A case report

BACKGROUND: Extranodal natural killer/T cell lymphoma, nasal type (ENKL) is a highly aggressive malignancy characterized by its association with Epstein-Barr virus (EBV) and extranodal involvement, which shows a poor clinical outcome. Although L-asparaginase-based chemotherapy has improved the response rates of relapsed/refractory (R/R) ENKL, relapse occurs in up to 50% of patients with disseminated disease. CASE SUMMARY: Immune evasion has emerged as a critical pathway for survival in ENKL and may be effectuated via STAT3-driven upregulation of programmed cell death ligand 1 (PD-L1) or other molecular pathways. Anti-PD-1 is effective for R/R ENKL with EBV-driven upregulation of PD-L1 expression. Anti-PD-1 combined with decitabine showed positive preliminary results in a patient with R/R ENKL and resistance to anti-PD-1. CONCLUSION: The treatment experience, in this case, demonstrated the potential ability of decitabine combined with PD-1 inhibitor to treat R/R ENKL, thus providing a new treatment strategy for this tumor.