Prognostic significance of T-cell phenotype in aggressive non-Hodgkin's lymphomas

Peripheral T-cell lymphomas (PTCL) have been generally reported to have a worse prognosis than B-cell lymphomas (BCL). Because of their heterogeneity and scarcity, the outcomes of the different histological subtypes have not been compared. From October 1987 to March 1993, 1,883 patients with diffuse aggressive non-Hodgkin's lymphomas (NHL) included in the LNH87 protocol could be assessed for both morphology and immunophenotyping. Among them, 288 (15%) had PTCL and 1,595 (85%) had BCL. According to the Kiel classification, most PTCL were classified as angioimmunoblastic (AIL; 23%), pleomorphic medium and large T-cell (PML; 49%), or anaplastic large cell (ALCL; 20%) lymphomas. Comparing PTCL with BCL patients, the former had more disseminated disease (78% v 58%), B symptoms (57% v 40%), bone marrow involvement (31% v 17%), skin involvement (21% v 4%), and increased beta(2)-microglobulin (50% v 34%), whereas BCL patients had more bulky disease (41% v 26%). According to the International Prognostic Index (IPI), PTCL and BCL scores were, respectively: 0 factors, 13% and 15%; 1 factor, 17% and 22%; 2 factors, 24% end 25%; greater than or equal to 3 factors, 45% and 37% (P = .09). For BCL and PTCL, respectively, complete remission rates were 63% and 54% (P = .004); the 5-year overall survival (OS) rates were 53% and 41% (P = .0004) and event-free survival (EFS) rates were 42% and 33% (P < .0001). Comparison of the different histological subtypes of lymphoma showed that the 5-year OS rate for T-ALCL (64%) was superior to those of other PTCL (35%) as well as diffuse large B-cell (53%) NHL. When multivariate analysis was applied using the IPI score as one factor, nonanaplastic PTCL remained an independent parameter (P = .0004). Although the poor prognosis of non-ALCL PTCL could be due in part to the presence of adverse prognostic factors at diagnosis, this study shows that the T-cell phenotype is an independent significant factor, which should be incorporated into the definition of prognostic groups. (C) 1998 by The American Society of Hematology