We designed a new treatment protocol incorporating concurrent administration of L-asparaginase (to reduce the probability of systemic progression during concurrent chemoradiotherapy (CCRT)) plus high-dose methotrexate to consolidation chemotherapy to intensify the regimen for treating localized extranodal NK/T cell lymphoma, nasal type (ENKTL). CCRT comprised radiation (36-44 Gy) with weekly cisplatin (30 mg/m2) and tri-weekly L-asparaginase (4 000 IU). Chemotherapy-MIDLE (methotrexate 3 g/m2 on day 1, etoposide 100 mg/m2 and Ifosfamide 1 000 mg/m2 on days 2-3, dexamethasone 40 mg on days 1-4, and L-asparaginase 6 000 IU/m2 on days 4, 6, 8, 10)-was repeated every 28 days for two cycles. One of the 28 patients developed distant lesions after CCRT. The final complete response rate was 82.1%. Four patients dropped out during or after their first MIDLE cycle due to toxicities (recurrent G3 hyperbilirubinemia [n = 1], G3-5 increased creatinine [n = 2], and G5 infection [n = 1]). With a median follow-up of 46 months (95% CI: 39-47 months), the estimated 3-year progression-free survival rate and overall survival rate were 74.1% and 81.5%, respectively. This MIDLE protocol may be effective for localized ENKTL. However, concurrent administration of L-asparaginase during CCRT does not seem to provide additional benefits.
Keywords: L-asparaginase; concurrent chemoradiotherapy; extranodal NK/T-cell lymphoma, nasal type; methotrexate; treatment.