Inclusion Criteria:

- Patients of 40 years of age or older, of either sex, who have given their informed
consent to participate in the study.

- Patients with a malignant neoplastic process (primary or metastasic) of the
gastrointestinal tract (except the oesophagus), genitourinary tract or female
reproductive organs, previously diagnosed and documented, and who are programmed to
undergo elective, open, curative or palliative surgery directly related to that
disease.

- Patients undergoing surgery with general or spinal anaesthesia, with an estimated
duration of surgery of over 30 minutes.

- Patients with a life expectancy of at least 3 months.

Exclusion Criteria:

- Curative or palliative surgery of a malignant neoplastic process in liver, biliary
tract or pancreas.

- Women who are pregnant or breast-feeding, or women with child-bearing potential who
are not using effective contraceptive methods.

- Patients with macrohaematuria, active haemorrhage within the past two months, organ
lesions at risk of bleeding (e.g. active peptic ulcer, haemorrhagic cerebrovascular
accident, aneurysms), a history of episodes of clinically evident haemorrhage, major
surgery in the previous month or an increase in the risk of bleeding due to any
disturbance of haemostasis which would contraindicate the anticoagulant therapy, with
the exception of bleedings episodes directly caused by tumour subjected to the
surgical intervention.

- Patients with known hypersensitivity to the LMWHs, to heparin or to substances of
porcine origin.

- Patients with known hypersensitivity to radiological contrast media.

- Patients with known hypersensitivity to anaesthetic drugs or pre-anaesthetic drugs.

- Patients with a congenital or acquired bleeding diathesis (confirmed by hematological
test), with or without haematuria.

- Lesions or surgical interventions of the central nervous system, eyes or ears within
the previous 6 months, including hemorrhagic or ischemic cerebro-vascular accident,
cerebral thrombosis and/or known cerebral metastasis.

- Disseminated Intravascular Coagulation (DIC) attributable to heparin-induced
thrombocytopenia.

- Acute bacterial endocarditis and slow endocarditis.

- Patients on treatment with oral or parenteral anticoagulants within 5 days before the
operation.

- Patients with a history of thrombocytopenia associated with heparin or with a current
platelet count <75,000/mm3.

- Patients with renal failure (defined as a serum creatinine over 2 mg/dL), hepatic
insufficiency (with AST and/or ALT values > 5 times over normal values established by
the reference range of the local laboratory of the hospital).

- Severe arterial hypertension (systolic blood pressure over 200 mmHg and/or diastolic
blood pressure over 120 mmHg).

- One or more documented episodes of DVT and/or PE (confirmed by a
ventilation-perfusion gamma scan or helical CT) in the previous 3 months.

- Patients with suspected or confirmed inability to comply with the study treatment
and/or follow-up.

- Patients who are participating in another clinical trial or who have done so in the
past 30 days.

- Patients with a cava vein filter in place.

- Patients needing the use of unallowed concomitant treatments or medications such as
more than 125mg/day aspirin, NSAIDs with long half-life of significant
anti-aggregation activity, metformin, or any anticoagulant compound (please refer to
section of the protocol "Concomitant medications and treatments" for details)