Clinical and prognostic differences between ALK-negative anaplastic large cell lymphoma and peripheral T cell lymphoma, not otherwise specified: a single institution experience.

Clinical differences between anaplastic lymphoma kinase (ALK)-negative anaplastic large-cell lymphoma (ALK(-) ALCL) and peripheral T cell lymphoma, not otherwise specified (PTCL-NOS), remain unclear. The aim of this study was to compare the clinical and prognostic features of these two lymphoma types. We retrospectively analyzed 167 patients with ALK(-) ALCL (n = 48) and PTCL-NOS (n = 119). Compared with ALK(-) ALCL patients, PTCL-NOS patients exhibited distinct differences in clinical features with a propensity for more advanced stages, frequent extranodal involvement, and a poor performance status, leading to a higher risk group according to the International Prognostic Index or Prognostic Index for PTCL-NOS. Patients with ALK(-) ALCL were associated with a higher complete response rate (47.9 vs. 31.0 %; P = 0.041) after initial chemotherapy than patients with PTCL-NOS. The prognosis was significantly different between two subtypes, with a 5-year overall survival (OS) rate of 57.9 % for ALK(-) ALCL and 23.9 % for PTCL-NOS (P = 0.002). The subgroup analysis showed significant differences in OS and progression-free survival between the two subtypes in early-stage diseases, but not in advanced-stage diseases. We conclude that patients with ALK(-) ALCL showed favorable clinical features, higher chemosensitivity, and a superior outcome than those with PTCL-NOS.