EFFECTS ON PLATELET-FUNCTION OF COMBINATION ETOPOSIDE AND CARBOPLATINCHEMOTHERAPY IN PEDIATRIC ONCOLOGY PATIENTS

The effects of a therapeutic course of the combination of carboplatin and etoposide on platelet function have been evaluated in 10 pediatric patients with brain tumors. Platelet count, in vitro aggregation test s, P-selectin expression and agonist-induced ATP release were evaluate d before, and 7 and 15 days after one cycle of chemotherapy. The analy sis of the results demonstrated the presence of an ill vitro platelet aggregation defect in response to collagen and arachidonic acid in all patients 7 days after therapy. A concomitant decrease of collagen- an d arachidonic acid-induced ATP release was also observed. Both platele t aggregation and ATP release returned to baseline values 15 days afte r chemotherapy administration. Conversely, in vitro platelet aggregati on and secretion induced by ADP and epinephrine were unaltered by carb oplatin and etoposide administration. Furthermore, P-selectin expressi on was negative at baseline and did not change after chemotherapy. The se results support the hypothesis that combination etoposide and carbo platin chemotherapy in pediatric patients is responsible for possible disturbances in biochemical pathways required far platelet secretion a nd aggregation.