Inclusion Criteria:

- Histologically confirmed adenocarcinoma of stomach or gastroesophageal junction

- Age ≥ 20 years

- Patients receiving curative or palliative abdominal surgery (lasting ≥ 30 minutes)
(both open and laparoscopic surgery will be included)

Exclusion Criteria:

- No histological confirmation

- Patients who already have VTE (or pulmonary embolism) at the screening periods of
this study

- Past medical history of VTE or pulmonary embolism

- Patients with the history of other cancer (Patients who were disease-free for > 5
years from previous other cancer is allowed to be included in this study)

- Patients with thrombophilia or other comorbidities requiring anticoagulation (i.e.
atrial fibrillation or cerebral infarct requiring anticoagulation