The study is designed to compare the efficacy and safety of oral rivaroxaban and subcutaneous low-molecular-weight heparin in preventing femoral venepuncture associated thrombosis among cancer patients.

Inclusion Criteria:

• Age 18 to 85
• Histologically or cytologically confirmed advanced or metastatic solid tumors
• Patients will be received femoral venepuncture for apheresis by cell separator, which is the necessary process to perform following adoptive cell immunotherapy.
• Estimated life expectancy > 3 months
• Adequate hematologic function, with WBC ≥ 3000/microliter, hemoglobin ≥ 9 g/dL (it is acceptable to have had prior transfusion), platelets ≥ 75,000/microliter; PT-INR <1.5 (unless patient is receiving warfarin in which case PT-INR must be <3), PTT <1.5X ULN
• Adequate renal and hepatic function, with serum creatinine < 1.5 mg/dL, bilirubin < 1.5 mg/dL (except for Gilbert's syndrome which will allow bilirubin ≤ 2.0 mg/dL), ALT and AST ≤ 2.5 x upper limit of normal.

Exclusion Criteria:

• known conditions associated with high risk of bleeding, known history of hemorrhagic diathesis
• Platelet count < 50 000 G/L
• Active bleeding
• Patients with a history of autoimmune disease, such as but not restricted to, inflammatory bowel disease, systemic lupus erythematosus, ankylosing spondylitis, scleroderma, or multiple sclerosis. Autoimmune related thyroid disease and vitiligo are permitted.
• Patients with obstructive jaundice
• Patients with Spleen hyperfunction
• Presence of an active acute or chronic infection including: a urinary tract infection, HIV (as determined by ELISA and confirmed by Western Blot). Patients with HIV are excluded based on immuno-suppression, which may render them unable to respond to the vaccine; patients with chronic hepatitis are excluded because of concern that hepatitis could be exacerbated by the injections.
• Pregnant or breast-feeding women，or lack of effective contraceptive treatment for women of childbearing age.;