Rivaroxaban Versus Low-molecular-weight Heparin for Preventing Thrombosis in 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.;