Complete remission after first-line radio-chemotherapy as predictor of survival in extranodal NK/T cell lymphoma

Background: Extranodal nasal-type NK/T-cell lymphoma is a rare and severe disease. Considering the rarity of this lymphoma in Europe, we conducted a multicentric retrospective study on nasal-type NK/T cell lymphoma to determine the optimal induction strategy and identify prognostic factors. Methods: Thirty-six adult patients with nasal-type NK/T-cell lymphoma were recruited and assessed. In total, 80 % of patients were classified as having upper aerodigestive tract NK/T-cell lymphoma (UNKTL) and 20 % extra-upper aerodigestive tract NK/T-cell lymphoma (EUNKTL). Results: For advanced-stage disease, chemotherapy alone (CT) was the primary treatment (84 % vs. 10 % for combined CT + radiation therapy (RT), respectively), while for early-stage disease, 50 % of patients received the combination of CT + RT and 50 % CT alone. Five-year overall survival (OS) and progression-free survival (PFS) rates were 39 % and 33 %. Complete remission (CR) rates were significantly higher when using CT + RT (90 %) versus CT alone (33 %) (p < 0.0001). For early-stage disease, CR rates were 37 % for CT alone versus 100 % for CT + RT. Quality of response was significantly associated with survival, with 5-year OS being 80 % for CR patients versus 0 % for progressive disease patients (p < 0.01). Conclusion: Early RT concomitantly or sequentially with CT led to improved patient outcomes, with quality of initial response being the most important prognosticator for 5-year OS.