The use of heparin for treating human malignancies.

There is a substantial amount of data implicating coagulation mechanisms in the pathogenesis of malignancy. Studies in some experimental animal models have shown that the anticoagulant heparin limits tumour growth and metastasis and prolongs survival. Experience with the effects of heparin on human malignancy is limited primarily to settings in which it was given either to prevent or to treat thrombosis in patients who also had cancer. However, these studies have shown noteworthy apparent improvement in cancer outcome with heparin, especially with low-molecular-weight heparin. There are several possible mechanisms by which heparin could potentially alter the natural history of cancer progression because of its ability to modify the cellular and molecular environment of tumour cells. This experience provides the rationale for definitive clinical trials of heparin in patients with cancer and also for further experimentation to define the mechanisms of antineoplastic activity by this familiar class of drugs.