The variables of interest include demographic information, clinical parameters (tumor type, extent of disease, clinical exam findings, and presence of comorbidities, diagnostic assessments, and treatment interventions), reason for rivaroxaban discontinuation and outcomes. The confidentiality of all patient-specific data will be maintained. By using Pharmacy Informatics and CS, we can capture most of patients prescribed rivaroxaban at the UT MDACC.This is a descriptive study and the final sample size will depend on available records for chart review from 01/01/2012 to 11/07/2016.