Extranodal natural killer/T-cell lymphoma (ENKTL) is an aggressive form of non-Hodgkin's lymphoma and shows extremely poor survival. This prospective pilot study to evaluate the efficacy and safety of long-acting aspargase (pegylated aspargase, PEG-ASP) combined with gemcitabine and oxaliplatin (PASP -Gemox) treatment in this population.

Eligibility criteria The eligibility criteria were pathologically confirmed, previously untreated or refractory/relapsed ENKTL as defined by the World Health Organization classification; age≥18 years; Eastern Cooperative Oncology Group (ECOG) performance status of 0-2; at least one measurable lesion; adequate haematologic function (haemoglobin > 9.0 g/l, absolute neutrophil count > 1500/ml, platelets > 75,000/l), hepatic function (total serum bilirubin ≤ 1.5 times the upper limit of normal, alanine aminotransferase and aspartate aminotransferase ≤ 2.5 times the upper limit of normal), renal function (serum creatinine ≤ 1.5 mg/dl, creatinine clearance ≥ 50 ml/min); normal coagulation function and electrocardiogram results. Prior chemotherapy and radiotherapy should have been completed >4 weeks earlier, willingness to provide written informed consent. Stage was defined according to the Ann Arbor system. The Sun Yat-Sen University Cancer Centre Research Ethics Board approved this study before subjects were enrolled.

Treatment PA-Gemox dosages were as follows: days 1 and 8, 30-min intravenous infusion of 1000 mg/m2 gemcitabine; day 1, 2-h intravenous infusion of 130 mg/m2 oxaliplatin; day 1, deep intramuscular injection of 2500 U/m2 PEG-ASP at two different sites. The regimen was repeated every 3 weeks for a maximum of six cycles. Stage IE/IIE patients underwent four cycles induction chemotherapy, followed by involved-field radiotherapy after got CR, PR or SD. Three-dimensional conformal radiotherapy was done by linear accelerator at 2.0 grays (Gy) per daily fraction with 5-6 weeks. The involved- field radiation (IFRT) dose was 50-56 Gy. Refractory/relapsed patients underwent at least two cycles treatments unless there was disease progression or unacceptable side effects, or withdrawal of patient consent. Autologous haematopoietic stem cell transplantation (AHSCT) was recommended after they achieved CR.

Inclusion Criteria:

1. pathologically confirmed, previously untreated or refractory/relapsed ENKTL as defined by the World Health Organization classification;
2. age≥18 years;
3. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2;
4. at least one measurable lesion;
5. adequate haematologic function (haemoglobin > 9.0 g/l, absolute neutrophil count > 1500/ml, platelets > 75,000/l),
6. adequate hepatic function (total serum bilirubin ≤ 1.5 times the upper limit of normal, alanine aminotransferase and aspartate aminotransferase ≤ 2.5 times the upper limit of normal),
7. adequate renal function (serum creatinine ≤ 1.5 mg/dl, creatinine clearance ≥ 50 ml/min);
8. normal coagulation function and electrocardiogram results.
9. Prior chemotherapy and radiotherapy should have been completed >4 weeks earlier,
10. willingness to provide written informed consent.

Exclusion Criteria:

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