The purpose of the study is to examine the efficacy and safety of prolonged thromboprophylactic treatment with Fragmin® in oesophageal cancer patients undergoing intended curative surgery.

Hypotheses

1. The intervention group of oesophageal cancer patients, who receive prolonged thromboprophylaxis with Fragmin® has a lower VTE risk, expressed by a lower prothrombin fragment F1+2, 30 days after surgery than the control group, who receive Fragmin® for 10 days.
2. The intervention group does not demonstrate an increased bleeding tendency compared with the control group.

Primary endpoint The primary endpoint is the difference in prothrombin fragment F1+2 30 days after surgery between the intervention and the control group.

Secondary and safety endpoints The secondary endpoints are incidence of bleeding, VTE and mortality 30 days and one year after surgery.

Study design

The study is comprised of three specific objectives, presented in three work packages (WP):

• WP1: Randomization of 100 oesophageal cancer patients undergoing intended curative surgery to either a 10 or 30-day prophylactic LMWH-regime.
• WP2: Investigation of the coagulation in the WP1 population. The aim is to substantially improve understanding of the coagulation pathophysiology and the mechanisms behind the increased thromboembolic risk in oesophageal cancer patients.
• WP3: The lectin pathway complement proteins are suspected to play a role in the increased risk of thrombosis in cancer. We aim to examine this further by measuring complement protein levels in the WP1 population and investigate if there is a correlation between complement levels and changes in the coagulation.

Inclusion Criteria:

1. Cancer located in oesophagus and/or cardia.
2. Candidate for intended curative surgery.
3. Age > 18 years.

Exclusion Criteria:

1. Known inherited bleeding disorder.
2. Unable to provide informed consent.
3. Arterial or venous thromboembolic events within the last three months.
4. On-going anticoagulant treatment (Vitamin K antagonists or direct oral anticoagulants).
5. Pregnant or has given birth within the last three months.
6. Known allergy to the trial drug Dalteparin (Fragmin®).

No masking due to ethical considerations. Primary outcome is biochemical.