[The prognostic significance of serum thymidine kinase in the myelodysplastic syndrome].

OBJECTIVE

To assess the prognostic value of serum thymidine kinase (sTK) activity in patients with the myelodysplastic syndrome (MDS).

PATIENTS AND

METHODS

The study included 255 patients (144 men, 111 women, median age 67 [14-97] years) in whom primary MDS had been diagnosed between 1986 and 1995 (refractory anaemia [RA]: n = 40; RA with ring sideroblasts: n = 38; RA with increased blasts: n = 76; RA with increased blasts in transformation: n = 45; chronic myelomonocytic leukaemia: n = 56). 69 healthy persons (28 men, 41 women, median age 33 [24-62] years) served as controls. The normal laboratory range for sTK was between 0.9 and 4.9 U/microliter.

RESULTS

At time of diagnosis 83% of patients had sTK levels higher than 5 U/microliter. There was no relationship between sTK levels and the proportion of medullary blasts. But serum sTK levels correlated with LDH activity (P < 0.0005) and with peripheral leukocyte count (P = 0.003). At all times patients with sTK levels < 10 U/microliter had a higher survival rate than those > or = 10 U/microliter. Cumulative survival rates in both groups was 69 +/- 10% (< 10 U/microliter) and 43 +/- 11% (> or = 10 U/microliter), respectively, after 2 years and 37 +/- 9% (< 10 U/microliter) and 20 +/- 7% (> or = 10 U/microliter) after 5 years (P = 0.0002). Multivariate analysis showed that sTK, haemoglobin concentration and proportion of medullary blasts were independent prognostic survival factors.

CONCLUSIONS

Most patients with MDS have an increased sTK level when the diagnosis is made. This reflects the impaired proliferation and differentiation of haematopoiesis. sTK is a simply and rapidly measured prognostic indicator for estimating survival probability of patients with MDS.