Effects on platelet function of combination etoposide and carboplatin chemotherapy in pediatric oncology patients

Abstract

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 tests, P-selectin expression and agonist-induced ATP release were evaluated before, and 7 and 15 days after one cycle of chemotherapy. The analysis of the results demonstrated the presence of an in vitro platelet aggregation defect in response to collagen and arachidonic acid in all patients 7 days after therapy. A concomitant decrease of collagen- and arachidonic acid-induced ATP release was also observed. Both platelet aggregation and ATP release returned to baseline values 15 days after chemotherapy administration. Conversely, in vitro platelet aggregation and secretion induced by ADP and epinephrine were unaltered by carboplatin and etoposide administration. Furthermore, P-selectin expression was negative at baseline and did not change after chemotherapy. These results support the hypothesis that combination etoposide and carboplatin chemotherapy in pediatric patients is responsible for possible disturbances in biochemical pathways required for platelet secretion and aggregation.