Inclusion Criteria:
- Male or female, >= 18 years old. There are no ethnic restrictions.
- Active cancers of the GI tract (gastroesophageal, colorectal, or pancreatic-biliary)
that have completed TNM staging by the American Joint Committee on Cancer; stage III
disease if diagnosed within 2 months and all stage IV disease
- Ability to understand and the willingness to sign a written informed consent
document.
- Existing staging CT imaging study
Exclusion Criteria:
- Life expectancy < 6 months
- History of deep vein thrombosis (DVT) or pulmonary embolism (PE)
- Known pregnancy or positive urine pregnancy test in pre-menopausal women
- On anticoagulant therapy (heparin, warfarin, direct thrombin inhibitors)
- No CT imaging studies, or contraindications to undergoing CT imaging
- Existing or anticipated need for a tunneled central venous catheter
- Clinic visitation to Stanford Cancer center for secondary consultation purposes only
- Inability to give informed consent