SERUM THYMIDINE KINASE AS A PROGNOSTIC INDICATOR FOR PATIENTS WITH MULTIPLE-MYELOMA - RESULTS FROM THE MRC (UK) V-TRIAL

The significance of serum thymidine kinase (STK) as a prognostic indic ator for patients with myeloma has been evaluated by determining the p re-treatment level of STK in a retrospective study of 547 patients fro m the Medical Research Council (MRC) V Myeloma Trial. Overall, STK was a highly significant prognostic factor (Chi2=7.91; P=0.005). At the t ime of censor, 23.4% of patients with a presentation STK of < 6 U/l bu t only 7.9% of the patients with an STK of > 11 U/l were still alive. STK proved to be a highly significant prognostic indicator for the 270 melphalan-treated patients (Chi2=12.37; P=0.0004) but had no prognost ic significance for the 277 ABCM (adriamycin, BCNU, cyclophosphamide a nd melphalan) treated patients (Chi2=0.29; P=0.59). When the STK data was stratified for serum B-2-microglobulin (SB2M) it was demonstrated that STK was independent of SB2M and provided additional prognostic in formation for patients who were treated with melphalan. Thus patients with both a low STK and SB2M had the best prognosis (median survival 1 677 d) and those patients with a high STK and SB2M had the worst progn osis (median survival 519 d). STK is a good prognostic marker for pati ents treated with melphalan but the prognostic significance of STK may disappear with the introduction of new chemotherapy regimens.