Risk classification for large cell lymphoma using lactate dehydrogenase, beta-2 microglobulin, and thymidine kinase

We have previously proposed a staging system for large cell lymphoma using the two serum markers beta-2-microglobulin (B₂M) and lactate dehydrogenase (LDH). We recently tested this model in a different cohort of patients with large cell lymphoma and also examined the possible contribution of thymidine kinase (TK), a previously reported serologic prognostic factor. Using an inclusion criteria in the multivariate analysis for both forward and backward selection of p < 0.15, only LDH, B₂M, and TK were significant independent prognostic factors for both time to treatment failure (TTF) and survival. Inclusion of TK in the serologic model resulted in three significantly different risk groups for both TTF and survival. Corresponding endpoints at three years were: 1) good risk (no markers elevated, n = 43): 78%, 91%; 2) intermediate risk (1 or 2 markers elevated, n = 47): 41%, 36%; 3) poor risk (3 markers elevated, n = 11): 0%, 0%. This analysis extends the observation of the independent prognostic significance of B₂M and LDH. The addition of TK permits a more precise estimate of risk, contributing to the utility of a serological staging system for large cell lymphoma.