SERUM BETA-2-MICROGLOBULIN AND SERUM THYMIDINE KINASE ARE INDEPENDENTPREDICTORS OF PROGRESSION-FREE SURVIVAL IN CHRONIC LYMPHOCYTIC-LEUKEMIA AND IMMUNOCYTOMA

Chronic lymphocytic leukemia (CLL) and immunocytoma (IC) are remarkabl y heterogeneous with regard to their clinical course. The current stag ing systems can distinguish prognostic subgroups, but do not seem to p redict the risk of disease progression of an individual patient with s ufficient accuracy. Given the increase of treatment options for CLL an d IC, additional parameters are needed to decide which patients may be nefit from early or intensified treatment. It has been shown that two biochemical markers, serum beta(2)-microglobulin (s-beta(2)M) and seru m thymidine kinase (s-TK), might identify CLL and IC patients at high risk of disease progression. Therefore, the prognostic value of these two serum parameters was compared with a panel of several established prognostic factors in a prospective clinical trial. 113 patients with CLL and 41 patients with IC (mean age +/- SD 63.9 +/- 10.7 years) were included. The following parameters were determined: histopathological diagnosis (IC vs. CLL), age, sex, performance status (Karnofsky index ), B symptoms, peripheral blood lymphocyte count, platelet count, bloo d hemoglobin, serum lactate dehydrogenase (s-LDH), s-beta(2)M, s-TK, s erum creatinine, number of lymph node areas involved, prior therapy, a nd the time from diagnosis to inclusion in the study. Univariate analy ses showed that nine parameters (Karnofsky index, peripheral blood lym phocytosis, platelet count, blood hemoglobin, lymph node areas involve d, pretreatment, s-LDH, s-beta(2)M, and s-TK) significantly predicted progression-free survival. In a Cox regression model, only four of the se parameters provided independent prognostic information on progressi on-free survival: 1. s-beta(2)M, 2. Karnofsky index, 3. platelet count , and 4. s-TK. The results show that s-beta(2)M and s-TK independently predict progression-free survival in patients with CLL and IC, and su ggest that these prognostic factors may allow an improved prediction o f progression-free survival, particularly in early disease stages.