Although the efficacy of low-molecular-weight heparins(LMWH) in the prophylaxis of postoperative venous thromboembolism (VTE) is well established in a large number of studies, some aspects remain to be determined. The optimal duration of prophylactic treatment has not been clearly defined yet.~Traditionally, surgical prophylaxis of VTE in patients undergoing high-risk orthopaedic surgery was extended for one or two weeks after the operation. However, the most recent studies carried out on this field have demonstrated that prolongation of prophylaxis with LMWH for 4-6 weeks significantly reduces the incidence of VTE (by more than half) in patients undergoing orthopaedic surgery with a high-risk of VTE.~On the contrary, thromboprophylaxis in oncological surgery is generally limited to the period of hospitalisation, despite the fact that activation of coagulation is greater and more prolonged in patients undergoing surgery for neoplastic processes than in those patients not affected by cancer. The only two studies carried out to evaluate the efficacy of the prolongation of thromboprophylaxis for 4 weeks in this type of surgery seem to indicate that the VTE incidence could be reduced even further that with one-week prophylaxis, though these do not allow to establish a definitive conclusion.~The present study aims to evaluate the efficacy and safety of Bemiparin, a second-generation LMWH, in the prophylaxis of VTE (using a postoperative regimen, giving the first dose 6 hours after finishing the surgical procedure) for 28 days compared to 8 days, in oncological surgery.~Additionally, some exploratory analyses will be carried out to evaluate:~The biological effect of the sc. administration of Bemiparin (3,500 IU/day) on different biological markers involved in the tumoral development and its metastasis in patients undergoing an oncological abdominal or pelvic surgical operation.~The effect of the sc. administration of Bemiparin (3,500 IU/day) on the evolution of the tumour in patients undergoing an oncological abdominal or pelvic surgical operation.~The effect of the sc. administration of Bemiparin (3,500 IU/day) on the survival of the patients at 6 months from the operation.~Four Study Committees have been created for this clinical trial in order to guarantee the safety of the patients as well as the highest quality data:~Trial Steering Committee~Data & Safety Monitoring Board~Committee for the Evaluation of Phlebographies~Committee for Adjudicating Clinical Events.
The aim of the study is to evaluate the efficacy and safety of Bemiparin, a second-generation LMWH, in the prophylaxis of VTE (using a postoperative regimen, i.e. administering the first dose 6 hours after finishing the surgical procedure) for 28 days compared to 8 days, in oncological surgery.