Beta-2 microglobulin: a prognostic factor in diffuse aggressive non-Hodgkin's lymphomas.

beta-2 microglobulin levels were measured in stored serum taken at presentation from 262 patients treated with combination chemotherapy for Kiel classification high-grade lymphoma at a single centre over a 15 year period. A significant association was found between elevated levels and advanced (Ann Arbor stage III or IV) disease or hepatic infiltration, but not with other sites of extranodal involvement or bulky disease. Patients with normal levels at presentation had a 70% remission rate with treatment compared to 37% of those with elevated levels (P < 0.001). With median follow up of 6 years duration of remission was significantly greater in patients with normal beta-2 microglobulin at presentation (plateau at 70%, compared to median remission of 19 months in those with raised levels, P < 0.001). Survival overall was also better in the group with normal levels (actuarial median 9 years compared to 1 year, P < 0.001). Multivariate analyses including treatment type, age, sex, B symptoms, stage, bulk, albumin, sodium, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase and beta-2 microglobulin, placed beta-2 microglobulin among the three most influential independent variables for prediction of response rate, duration of remission and overall survival.