ONE WEEK VERSUS FOUR WEEK HEPARIN PROPHYLAXIS AFTER LAPAROSCOPIC SURGERY FOR COLORECTAL CANCER.

Inclusion Criteria: * Consecutive patients who had * planned laparoscopic surgery for * colorectal cancer will be included in the study provided no exclusion criteria will be found Exclusion Criteria: * age \< 18 years * surgery for non-cancer disease * duration of surgery \< 45 min * other indication for anticoagulant therapy * known cerebral metastases * kidney or liver failure * known hemorrhagic diathesis or high risk for bleeding * history of intracerebral bleeding or neurosurgery within 6 months, history of heparin induced thrombocytopenia * pregnancy or lactation * refusal of informed consent.