Apixaban or Dalteparin in Reducing Blood Clots in Patients With Cancer Related Venous Thromboembolism

Inclusion Criteria: * Confirmed acute lower extremity or upper extremity (jugular, innominate, subclavian, axillary, brachial) DVT, PE, splanchnic (hepatic, portal, splenic, mesenteric, renal, gonadal), or cerebral vein thrombosis * Active cancer defined as metastatic disease and/or any evidence of cancer on cross-sectional or positron emission tomography (PET) imaging, cancer related surgery, chemotherapy or radiation therapy within the past 6 months; note: non-melanoma skin cancer does not meet the cancer requirement * Life expectancy \>= 60 days * Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0, 1, or 2 * Obtained =\< 30 days prior to randomization: Platelet count \>= 50,000/mm\^3 * Obtained =\< 30 days prior to randomization: Alanine aminotransferase (ALT) or aspartate transaminase (AST) =\< 3 x upper limit of normal (ULN) * Obtained =\< 30 days prior to randomization: International normalized ratio (INR) =\< 1.6 (if not taking anticoagulant therapy) * Obtained =\< 30 days prior to randomization: Calculated creatinine clearance must be \>= 30 ml/min using the Cockcroft-Gault formula * Negative serum or urine pregnancy test done =\< 24 hours prior to randomization, for women of childbearing potential only; note: a women of childbearing potential (WOCBP) is defined as any female who has experienced menarche and who has not undergone surgical sterilization (hysterectomy or bilateral oophorectomy) and is not postmenopausal; menopause is defined as 12 m…