A study analyzing five randomized controlled trials involving 1745 patients with metastatic cancer found that combination treatment with bevacizumab and chemotherapy was associated with an increased risk of arterial thromboembolic events compared to chemotherapy alone. The hazard ratio (HR) for arterial thromboembolic events was 2.0 (95% CI = 1.05 to 3.75; P = .031), while there was no significant increase in venous thromboembolic events (HR = 0.89, 95% CI = 0.66 to 1.20; P = .44). The absolute rate of arterial thromboembolic events was 5.5 per 100 person-years for those receiving combination therapy and 3.1 per 100 person-years for those receiving chemotherapy alone. Risk factors for arterial thromboembolic events included a prior arterial thromboembolic event and age of 65 years or older. Baseline or on-study aspirin use was associated with modest increases in grade 3 and 4 bleeding events in both treatment groups. The study concluded that combination treatment with bevacizumab and chemotherapy was associated with an increased risk of arterial thromboembolism but not venous thromboembolism. The risk factors for arterial thromboembolism should be considered when making treatment decisions for individual patients. Limitations included the potential overestimation of risk due to delayed time to progression and the inability to assess associations between risk and different tumor types, chemotherapeutic agents, or disease settings. The study also found that the use of low-dose aspirin did not substantially increase the risk of serious bleeding compared to aspirin and chemotherapy alone. The use of low-dose aspirin for the prophylaxis of arterial thromboembolic events in high-risk patients is supported by an extensive body of literature and is a recommended standard of care. The study highlights the importance of considering risk factors when making treatment decisions for patients with metastatic cancer.A study analyzing five randomized controlled trials involving 1745 patients with metastatic cancer found that combination treatment with bevacizumab and chemotherapy was associated with an increased risk of arterial thromboembolic events compared to chemotherapy alone. The hazard ratio (HR) for arterial thromboembolic events was 2.0 (95% CI = 1.05 to 3.75; P = .031), while there was no significant increase in venous thromboembolic events (HR = 0.89, 95% CI = 0.66 to 1.20; P = .44). The absolute rate of arterial thromboembolic events was 5.5 per 100 person-years for those receiving combination therapy and 3.1 per 100 person-years for those receiving chemotherapy alone. Risk factors for arterial thromboembolic events included a prior arterial thromboembolic event and age of 65 years or older. Baseline or on-study aspirin use was associated with modest increases in grade 3 and 4 bleeding events in both treatment groups. The study concluded that combination treatment with bevacizumab and chemotherapy was associated with an increased risk of arterial thromboembolism but not venous thromboembolism. The risk factors for arterial thromboembolism should be considered when making treatment decisions for individual patients. Limitations included the potential overestimation of risk due to delayed time to progression and the inability to assess associations between risk and different tumor types, chemotherapeutic agents, or disease settings. The study also found that the use of low-dose aspirin did not substantially increase the risk of serious bleeding compared to aspirin and chemotherapy alone. The use of low-dose aspirin for the prophylaxis of arterial thromboembolic events in high-risk patients is supported by an extensive body of literature and is a recommended standard of care. The study highlights the importance of considering risk factors when making treatment decisions for patients with metastatic cancer.