Heparins and cancer survival: where do we stand?

The relationship between cancer and thrombosis is a complex one with the haemostatic system and mechanisms of cancer growth and metastasis inextricably linked. The possibility that antithrombotics may confer a survival benefit on cancer patients has been considered for over sixty years, over which time a growing body of evidence has suggested that drugs such as low molecular weight heparins may inhibit cancer growth and metastasis through a myriad of mechanisms. Much of the trial data suggesting a survival benefit has been obtained through secondary subgroup analyses in highly heterogeneous populations. To date no sufficiently powered studies have been undertaken which support the routine use of LMWH to improve survival in cancer patients. This paper will review the current evidence around the topic to identify where we currently stand in this exciting yet challenging field.