Qualitative platelet dysfunction following cancer chemotherapy: a case report

Combination chemotherapy for breast carcinoma using a combination of cyclophosphamide, methotrexate and 5-fluorouracil (CMF) causes a platelet aggregation defect

Various coagulation parameters including platelet aggregation were evaluated during the course of treatment in 25 patients with breast carcinoma receiving a combination of cyclophosphamide, methotrexate and 5-fluorouracil (CMF). No significant changes were found in whole blood clotting time (WBCT), prothrombin time (PT), kaolin cephalin clotting time (KCCT), platelet count (PC) and prothrombin consumption index (PCI). The CMF combination induced a significant reduction in platelet factor-3 (PF3) availability and reduction in platelet aggregation to ADP and adrenaline. These defects occurred without development of thrombocytopenia. The changes occurred on the 8th day of chemotherapy and a progressive suppression in platelet aggregation was noted during subsequent follow-up. This acquired abnormality in platelet aggregation and PF3 availability may be responsible for various hemorrhagic manifestations such as mucositis, epistaxis and hemorrhagic cystitis following CMF therapy. Further, these changes precede the onset of life-threatening complication of thrombocytopenia. The study of platelet aggregation should be considered besides platelet counting in patients on CMF combination to assess bleeding diathesis.

Platelets acquire a secretion defect after high-dose chemotherapy

Patients receiving high-dose chemotherapy (HDC) and autologous bone marrow transplantation (ABMT) may experience life-threatening hemorrhagic myocarditis. The authors investigated whether HDC was associated with an acquired platelet defect. Platelet aggregation and release were evaluated after HDC in ten patients with either metastatic breast carcinoma or melanoma. Platelets underwent shape change and a primary wave of aggregation. High-dose chemotherapy was associated with the inhibition of secondary aggregation of platelets induced by adenosine diphosphate (ADP), arachidonic acid, prostaglandin H2 (PGH2) analog (U44619), and collagen. Although electron microscopic study of the platelets revealed normal morphologic features with an adequate number of dense bodies and alpha-granules, release of adenosine triphosphate (ATP) from dense granules was less than 20% of normal. The acquired platelet defect occurred before development of thrombocytopenia. Aggregation of platelets from normal volunteers was not inhibited by either the addition of the chemotherapeutic agents, chemotherapy metabolites, or the patients' sera. In conclusion, HDC induces an acquired abnormality in platelet secretion and aggregation which may contribute to the development of hemorrhagic complications after ABMT.