[Development and dissemination of malignant tumors, and hemostasis]

Strong circumstantial evidence suggests that the activation of the hemostatic system is involved in the growth and spread of malignant tumors. Nevertheless, the considerable experimental and clinical data presently available cannot be interpreted in one specific direction. The presence of a fibrin and/or a platelet thrombus in the environment of tumor cells only represents the visible end product of a complex biochemical and biophysical process during which other phenomena like haemodynamic changes and the generation of many biologically active enzymes occur. In the interpretation of experimental studies and clinical trials of anticoagulants in cancer disease, a wider concept of the hemostatic process and its multiple interactions with other biological systems is needed. The complement system, adhesive glycoproteins of the cell surface, chemotaxis, growth factors and prostaglandins are some examples of factors which interact with the hemostatic system as well as with the pathology of cancer. The definite pathogenic connection between the clinically observed hypercoagulability of patients with malignant disease and the biology of tumor growth and tumor dissemination remains unclear. Agents which modify hemostatic reactions must be evaluated in specific tumor categories using carefully controlled prospective trials. The results of such studies on tumor regression and also on longevity will permit to assess the efficacy of these agents as adjuvant therapy in the treatment of cancer.