This retrospective descriptive study will review charts of approximately375 cancer patients prescribed rivaroxaban from January 1, 2012 to November 7, 2016 at UT MDACC for NVAF or patients that had prior VTE and diagnosis of cancer. The list of patients prescribed rivaroxaban during the study period will be obtained from Pharmacy Informatics. We will review the eligibility of all patients on the pharmacy list who were prescribed rivaroxaban during the study time-frame. The eligible patients who meet inclusion/exclusion criteria will be identified. All available data concerning demographic, clinical parameters and rivaroxaban usage will be collected for eligible patients from Pharmacy Informatics, CS, Laboratory Informatics, and Clinical Informatics Databases.