History of any arterial thrombotic event within months prior to enrollment. History of bleeding disorders or thromboembolic events in prior months History of thromboembolic disease or uterine cancer that is considered a contraindication to tamoxifen Women with active liver disease or thromboembolic disorder. Patients will be excluded if any of the following are present, evidence of active bleeding, intratumoral hemorrhage, or bleeding diathesis; History (within months prior to study enrollment) of arterial thromboembolic events, including transient ischemic attack (TIA) or cerebrovascular accident (CVA); history (within months prior to study enrollment) of pulmonary embolism, deep venous thrombosis (DVT), or other venous thromboembolic event; history of clinically significant bleeding within weeks prior to study enrollment. Patients with prior history of a thromboembolic event within the last months that is not being treated with systemic anticoagulation are excluded Uncontrolled thromboembolic events or recent severe hemorrhage >= grade thromboembolic event in the last months History of any arterial thromboembolic event within months prior to first dose of investigational product Any history of arterial or venous thrombosis/thromboembolic event, including pulmonary embolism within the past months prior to registration. Patients with thromboembolic disease and on anticoagulation Willing and able to receive adequate prophylaxis and/or therapy for thromboembolic events Has a history of deep venous thrombosis/embolism, threatening thromboembolism or known thrombophilia or are at a high risk for a thromboembolic event in the opinion of the investigator and who are not willing/able to take venous thromboembolic event prophylaxis during the entire treatment period History of arterial thromboembolic events in the past months and of venous thromboembolic events in the past month Arterial or venous thromboembolic events within months of study enrollment History of arterial thromboembolic event History of arterial thromboembolic events or symptomatic pulmonary embolism within the past months Prior history of a thromboembolic event within the last two years and not currently on systemic anticoagulation Subjects must not have a history of thromboembolic disorder or cerebral vascular disease Subject has a history of thromboembolic event within the past weeks prior to enrollment. A history of thromboembolic disorder Recent arterial thromboembolic event within the previous months History of arterial thromboembolic events History of thromboembolic episodes =< months prior to registration Patients with evidence of active bleeding, intratumoral hemorrhage, or bleeding diathesis are not eligible:\r\n* History (within days prior to study enrollment) of arterial thromboembolic events, including transient ischemic attack (TIA) or cerebrovascular accident (CVA)\r\n* History (within days prior to study enrollment) of pulmonary embolism, deep vein thrombosis (DVT), or other venous thromboembolic event\r\n* History of hemoptysis within days prior to study enrollment Patients who have had a thromboembolic event that is not line-related are excluded The participant experienced any arterial thromboembolic event within months. The participant experienced any Grade or venous thromboembolic event that is not adequately treated. History of arterial thromboembolic events or symptomatic pulmonary embolism within months of study enrollment be able and willing to receive adequate prophylaxis and/or therapy for thromboembolic events Patients with history of thrombophlebitis within the past years or ongoing thromboembolic disorders have experienced any arterial thromboembolic event within months prior to enrollment have experienced any Grade or venous thromboembolic event that is considered by the investigator to be life threatening or that is symptomatic and not adequately treated by anticoagulation therapy, within months prior to enrollment Evidence or history of thromboembolic, venous, or arterial events within the past months Subjects who are at a risk for a thromboembolic event and are not willing to take prophylaxis for it. High risk of developing thromboembolic events, who are unwilling to take venous thromboembolism prophylaxis. History of arterial thromboembolic (arterial blood clot) or hemorrhagic event with the exception of patients with pulmonary embolism stable on an anticoagulation regimen Patients who have had a venous thromboembolic event (e.g., pulmonary embolism or deep vein thrombosis) requiring anticoagulation and who meet any of the following criteria:\r\n* Have been on a stable dose of anticoagulation for < month\r\n* Have had a grade , or hemorrhage in the last days\r\n* Are experiencing continued symptoms from their venous thromboembolic event (e.g. continued dyspnea or oxygen requirement); NOTE: Patients who have had a venous thromboembolic event but do not meet any of the above three criteria are eligible for participation Has a history of thromboembolic or cerebrovascular events within months prior to registration History of any of the following during first-line therapy with a bevacizumab-containing regimen: arterial thrombotic/thromboembolic event, bowel perforation, Grade hypertension, Grade proteinuria or Grade - bleeding event. Thrombotic/ thromboembolic event requiring systemic anticoagulation within days prior to enrollment History of thrombosis or thromboembolic event within last days prior to study entry Low-dose aspirin (=< mg/day) may be continued in subjects at higher risk for arterial thromboembolic disease At high risk for a venous thromboembolic event (VTE) and not willing to take VTE prophylaxis Patients with evidence of active thromboembolic disease, recent history of thromboembolic disease within the past months, or risk factors for thromboembolic disease (excluding thrombosis of a central line) History of thromboembolic disease within the past months regardless of anti-coagulation History of medically significant thromboembolic events or bleeding diathesis within the past months History of Grade or greater thromboembolic events in the prior months Thromboembolic events, stroke, or ST-elevated myocardial infarction within days of surgery. History of severe haemorrhagic or thromboembolic event in the past months Thromboembolic or myocardial infarction event within months Diagnosed venous thromboembolic disease within the preceding months (patient on full dose or prophylactic anticoagulation are eligible) Thrombotic or thromboembolic events within the past months: History of arterial thromboembolic disease within months of first study treatment History of a thrombotic or thromboembolic event (arterial or venous) in the past months Thromboembolic events, Participants with evidence of active thromboembolic disease or a history of thromboembolism within the preceding months (excluding thrombosis of a central line) History of arterial or venous thromboembolic disease months prior to screening History of thromboembolic disease (history of varicose veins and superficial phlebitis is allowed) Current thromboembolic disease requiring full-dose anticoagulation patients receiving pharmacologic prophylaxis for thromboembolic disease will be eligible History of arterial or venous thromboembolic event within months prior to study participation Treatment of a thromboembolic event =< months prior to randomization Prior history of documented venous thromboembolic event within the last years (excluding central line associated events whereby patients completed anticoagulation) A history of thromboembolic disorder or cerebral vascular disease Subjects must not have a history of myocardial infarction within months or a history of arterial thromboembolic event within months of the first dose of investigational agent.