Background: Direct oral anticoagulants (DOAC) such as Apixaban and Rivaroxaban are increasingly used for the treatment of acute venous thromboembolism (VTE) over traditional vitamin K antagonists. Malignant neoplasms predispose to acute VTE and clinical management necessitates anticoagulation to prevent further complications. We compare Apixaban to Rivaroxaban for the treatment of acute VTE in the setting of malignancy with the endpoint of chronic deep venous thrombosis (DVT) development after 2 years. Methods: The TriNetX Research network was used for this study. TriNetX provides access to anonymized medical record information on more than 107 million patients in 76 large healthcare organizations. Two cohorts were created for this study using the International Classification of Disease-10 (ICD-10) codes. All patients were required to have a diagnosis of breast (C50), lung (C34), colon (C18), or prostate cancer (C61). All were diagnosed with acute deep venous thrombosis (DVT) of the lower extremities (I82.409). One cohort was treated with rivaroxaban while the other was treated with apixaban within 3 days of DVT diagnosis. Each cohort was excluded from being treated with the other anticoagulant. The cohorts were balanced for age, race, gender, and ethnicity, then evaluated for the development of chronic DVT (I82.509) within the subsequent twelve months. Results: The development of chronic DVT was significantly more common in the apixaban cohort, with a risk ratio of 1.36 (95% CI (1.12,1.65), p-value 0.0015). See table. Conclusions: Patients with acute VTE in the setting of malignancy were at a significantly higher risk of developing chronic DVT following treatment with Apixaban compared to those who received Rivaroxaban at 2 years post-treatment. These results may contribute to increased discussion between physicians and patients when deciding between these two direct oral anticoagulants for the management of acute VTE. Diagnosis of chronic DVT in cancer patients treated with apixaban and rivaroxaban.