Prognostic significance of the immunophenotype versus the International Prognostic Index in aggressive non-Hodgkin's lymphoma.

The International Prognostic Index (IPI) is currently the most widely accepted prognostic factor system for patients with aggressive non-Hodgkin's lymphoma (NHL). However, in constructing the model, the immunophenotype of the disease was not used as an independent variable. The purpose of the present study was to assess and compare the prognostic significance of the immunophenotype (B-cell vs. T-cell) of aggressive NHL with other well-established prognostic determinants, in particular the IPI. Between January 1995 and December 2000, a retrospective analysis was conducted of clinical and pathological data on 181 patients aged = 15 years who had been newly diagnosed with aggressive NHL. All pathology slides were reviewed and defined according to the Revised European-American Lymphoma classification. Forty-one patients (23%) had T-cell lymphoma and 140 patients (77%) had B-cell lymphoma. Diffuse large B-cell lymphoma and unspecified peripheral T-cell lymphoma were the 2 most common entities, comprising 63% and 14% of patients, respectively. Most of the pretreatment characteristics, including IPI risk groups, were not significantly different between B-cell and T-cell lymphomas. The rates of complete remission (71% vs. 54%, P = 0.038) and progressive disease (39% vs. 63%, P = 0.023) significantly favored patients with B-cell lymphoma. With a median follow-up time of 31 months (range, 10-81 months), the 5-year overall survival (49% vs. 27%; P < 0.001) and event-free survival (35% vs. 10%; P < 0.001) were significantly better in B-cell lymphoma. The 5-year disease-free survival was also in favor of the B-cell group (48% vs. 21%; P = 0.086). Patients with T-cell lymphoma yielded inferior survival in all IPI risk groups. Multivariate analysis revealed T-cell lymphoma as the most significant factor associated with short overall survival (relative risk [RR], 3.4; 95% CI, 1.9-5.9) and event-free survival (RR 2.7, 95% CI, 1.7-4.3). When a second multivariate analysis was done using IPI (age, stage, performance status, number of extranodal sites, and serum lactate dehydrogenase) as one independent variable, T-cell phenotype remained the strongest factor affecting the survival of patients (P < 0.001). T-cell lymphoma is an independent prognostic factor, the significance of which is at least comparable to the IPI for patients with aggressive NHL.