Paraproteins may act as brakes in the sequential steps of the clotting cascade. Necrotic changes in the primary or metastatic malignancy may release kinases that are able to activate the clotting or fibrinolytic pathways, thus triggering intravascular coagulation or fibrinolysis. Tumor emboli may become the nucleus of intravascular defibrination. Extensive involvement of the liver and other organs by tumor may lead to inadequate synthesis of clotting factors. ![]() Autologous platelet antibodies causing thrombocytopenia may develop spontaneously or, more often, after multiple platelet transfusions. 1 Amegakaryocytic thrombocytopenia may follow extensive involvement of the bone marrow by malignant tissue, as well as radiation and chemotherapy. Hemostatic breakdown with overt hemorrhage in patients with cancer has many causes. Zinc deficiency should be suspected in patients with advanced cancer demonstrating bleeding when a prolonged bleeding time is the only hemostatic abnormality. Severe depletion of zinc in two patients with advanced cancer and malnutrition was accompanied by cutaneous bleeding and laboratory findings of platelet dysfunction, both of which were corrected by oral supplementation of zinc and reoccurred on discontinuing therapy. Discontinuation of zinc caused the return of bleeding and abnormal laboratory findings, which again were corrected with zinc supplementation. Oral administration of zinc without any additional therapy was rapidly followed by control of bleeding, normalization of bleeding time, and platelet aggregation. The mean values of zinc in the serum and urine of the 15 patients newly diagnosed with cancer were 109.18 μg/dL and 433.8 μg/24 hours, respectively. The two patients were found to have very low serum and urine zinc levels, which were 6 and 9 μg/dL and 28 and 22 μg/24 hours, respectively, compared with normal average values of 70–150 μg/dL and 150–1200 μg/24 hours. ![]() ![]() Also studied were serum and urine zinc levels in 15 newly diagnosed, untreated cancer patients with no evidence of bleeding. On the basis of previous studies, the author measured the level of zinc in the serum and urine of these patients and the effect of zinc supplementation on the clinical symptoms and laboratory findings. One patient with metastatic squamous cell carcinoma of the larynx and one with advanced non-Hodgkin lymphoma, both with poor nutritional status, developed ecchymoses and demonstrated prolonged bleeding time and abnormal aggregation of platelets.
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