Serum lactate dehydrogenase fails to predict response to treatment and survival in acute non-lymphocytic leukemia

Total serum lactate dehydrogenase (LDH) activity was measured in 514 adult patients with de novo acute non-lymphocytic leukemia (ANLL) prior to any treatment and was compared with several disease features, with response to induction treatment, and with relapse-free survival. LDH was higher in the M4 and M5 FAB cytological subtypes and was positively correlated with the white blood cell count (WBC). The proportion of remissions, of deaths during induction, and of failure, and the duration of relapse-free survival, were clearly unrelated to LDH activity, in the whole series as well as in different age groups (below 40 years, and 40 to 60 years) and in any FAB cytological subtype. Multivariate analysis showed that only WBC and sex (female better than male) were marginally related with relapse-free survival. These data provide conclusive evidence that LDH does not help in defining the prognosis of adult ANLL, either because enzyme activity fails to reflect the number and proliferation rate of leukemic cells efficiently, or because with current standard treatment these features are of borderline importance, in contrast with acute lymphocytic leukemia and malignant lymphomas.