Status of ongoing collaborative efforts.

T-cell lymphomas are the rarest of all non-Hodgkin lymphomas (NHLs) and may therefore be the least understood. The aim of the T-Cell Project is to pool prospective data from centers around the world to improve understanding of the more frequent and the uncommon subtypes of T-cell lymphomas. To be eligible for enrollment in this study, patients must have previously untreated, de novo peripheral T-cell lymphoma (PTCL) or natural killer (NK)/T-cell lymphoma and be at least 18 years of age. As of October 2009, 479 patients from 13 centers were enrolled, and 454 of these cases were validated. The patients are evaluated for their responses to treatment, progression-free and overall survival, and treatments received.