Cell proliferation as a long-term prognostic factor in diffuse large-cell lymphomas.

The relevance of cell proliferation rate--defined as the 3H-thymidine labeling index (3H-dT LI)--in predicting response to treatment (complete remission, CR), freedom from progression (FFP) and overall survival (OS) was evaluated in 86 patients with diffuse large-cell lymphoma (DLCL). The biologic variable was not associated with most of the established clinical factors, such as gender and age of the patient, performance status, B symptoms, tumor bulk, or extranodal disease, but was directly related to stage. 3H-dT LI significantly predicted short- and long-term clinical outcome. In fact, more patients with slowly proliferating DLCL reached CR and had longer median FFP and OS than patients with rapidly proliferating DLCL. Multiple-regression analysis to evaluate the relative contribution of the different biologic and clinical variables in predicting CR, FFP and OS showed that 3H-dT LI and Ann Arbor stage were the only 2 stable factors, which retained their prognostic significance even in the presence of other conventional factors, and that 3H-dT LI was the most powerful as an indicator of risk of death in DLCL patients.