Immature and absolute platelet count changes and thrombocytopenia in malignant glioma.

P>Background Temozolomide (TMZ) is commonly used for the therapy of malignant glioma and induces thrombocytopenia in a fraction of patients. Currently, no biomarkers predicting TMZ-induced thrombocytopenia are available. In this study, we investigated whether changes in platelet count (PLT) or the immature platelet fraction (IPF) may serve as predictor of TMZ-induced thrombocytopenia in malignant glioma patients. Methods We prospectively included 52 malignant glioma patients receiving TMZ-containing therapy regimens in this study. Platelet counts and IPF were determined at each clinical follow-up visit (weekly during concomitant radiochemotherapy or at least monthly during TMZ monotherapy) using the Sysmex XE-2100 system. We explored the diagnostic utility of PLT change/day and IPF change/day from the last to the current follow-up visit for the prediction of clinically relevant thrombocytopenia (PLT < 100 center dot 000 mu l-1) at the next follow-up visit. Results Relevant thrombocytopenia was observed in 10 of 234 occasions. The areas under the receiver operating characteristic curves for PLT absolute change/day, PLT relative change/day and IPF relative change/day were 0 center dot 675, 0 center dot 703 and 0 center dot 663, respectively. The Youden indices (maximum sum of sensitivity and specificity minus one) were 0 center dot 31, 0 center dot 39, and 0 center dot 29, respectively. The corresponding positive predictive values were 16%, 57%, and 6 center dot 7%, and the negative predictive values were 97%, 97%, and 98%, respectively. Conclusions The rather moderate diagnostic potential of our data indicate that the time course of PLT counts and IPF measured at routine clinical follow-up are not useful for the prediction of thrombocytopenia in glioma patients treated with TMZ.