Background Extranodal natural killer (NK) T-cell lymphoma (ENKTL) is a unique clinicopathological entity, typically
associated with poor survival outcomes. Most published data have come from east Asian study groups, with little
information available from international cohorts. The effects of treatment advances on routine clinical practice across
continental territories has not been clear. We aimed to improve understanding of the clinical characteristics and
outcomes of patients with ENKTL.
Methods We did a substudy of patients with ENKTL from the T-cell Project, a global prospective cohort study. The
T-cell Project registered consecutively diagnosed adults (>18 years) with newly diagnosed, untreated mature T-cell or
NK lymphomas (WHO 2001 or 2008 classifications) from 74 centres in 13 countries (in Asia, Europe, North America,
and South America). In total, 1695 patients with mature T-cell or NK lymphomas were enrolled between Oct 12, 2006
and Feb 28, 2018 in the T-cell Project. The first patient with ENKTL was enrolled on Feb 15, 2007, and the last on
May 26, 2017. Data on baseline characteristics, first-line treatment, treatment response, and survival outcomes were
recorded in a central database (locked March 30, 2019). The primary outcome was 5-year overall survival. The T-cell
Project is registered on ClinicalTrials.gov, NCT01142674.
Findings 166 patients were diagnosed with ENKTL, comprising 11% of 1553 eligible registered cases and distributed
across 40 participating centres in four continents. At a median follow-up of 44 months (IQR 20–61), overall survival at
5 years was 54% (95% CI 44–63) in patients with nasal disease (n=98) and 34% (27–46) in patients with extranasal
disease (n=68).
Interpretation To our knowledge, this study presents the largest international cohort of patients with ENKTL.
We describe a clinically significant improvement in the survival of patients with ENKTL treated in routine clinical
practice over the past decade, likely to be attributable to the increasing use of treatment protocols specific for
ENKTL.
Funding The Fondazione Cassa di Risparmio di Modena, the Associazione Angela Serra per la Ricerca sul Cancro, the
Fondazione Italiana Linfomi, Allos Therapeutics, Spectrum Pharmaceuticals, Associazione Italiana per la Ricerca sul
Cancro, and the National Cancer Institute at the National Institutes of Health.