Management of Advanced and Relapsed/Refractory Extranodal Natural Killer T-Cell Lymphoma: An Analysis of Stem Cell Transplantation and Chemotherapy Outcomes

We present a cohort of primarily non-Asian patients with advanced stage and relapsed/refractory ENKL. Our results demonstrate that achievement of complete response (CR) is imperative at all stages of disease in order to attain long-term disease control. The SMILE regimen was effective in relapsed/refractory disease to achieve complete remission. Autologous stem cell transplant should be strongly considered in patients with advanced ENKL who achieved CR, whereas allo-SCT can be considered for select patients who have not attained a CR. Background: Extra-Nodal natural killer/T-cell lymphoma (ENKL) is a rare lymphoma representing approximately 5-10% of T-cell non-Hodgkin lymphomas diagnosed in the United States each year. Patients with advanced stage III/IV ENKL and relapsed refractory ENKL have a poor prognosis even despite aggressive therapy and stem cell transplantation (SCT). We conducted a review of the management of 37 patients with advanced-stage and relapsed/refractory ENKL in a predominantly non-Asian cohort evaluating both chemotherapy and SCT outcomes. Patients and Methods: We evaluated clinical outcomes in all patients treated for advanced stage III/IV or relapsed/refractory ENKL at MD Anderson cancer center between 2000-2014. Next, we collected stem cell transplant data from four transplant institutions to further evaluate outcomes of both allogeneic (allo-SCT) and autologous (auto-SCT) stem cell transplantation in ENKL. Results: OS and PFS were 73% and 45% at one year, and 30% and 19% at 3-years, respectively. SMILE chemotherapy was more effective in maintaining a CR compared to CHOP (83% vs 17%). Only achievement of CR was prognostic for OS (HR 0.245, p=0.002) and PFS (HR=0.072, p) Conclusion: Our results suggest that achievement of a CR is imperative in patients with advanced ENKL, and is desirable for any patient for whom auto-SCT is utilized. SMILE-based chemotherapy appeared effective in attaining a CR, and was also an effective salvage regimen. For patients attaining a first CR, auto-SCT should be strongly considered, but should definitely be utilized in patients attaining CR2. For patients with refractory disease, allo-SCT can be considered in a selected group of patients.