Oncology data collection and management has not been effectively implemented within Veterans Health Information Systems and Technology Architecture (VistA). Computerized Patient Record System (CPRS) lacks critical functions required for oncology. This creates a clinical environment with a lack of standardization and limited direct order entry of chemotherapy. On a site-by-site basis, the current hybrid oncology practice is a mix of paper-based and computer-based practices and is associated with frequent error, adverse events, and inefficiencies. For these reasons, the VHA Patient Safety Workgroup has rated this issue as having a high level of patient safety risk. The web-based COMS prototype consisted of a general application interface and five modules (Chemotherapy Template Order Source, Order Entry Management, Nursing Documentation, Flow Sheet, and End of Treatment Summary) to support the unique needs of chemotherapy ordering and standardized capabilities to meet direct entry of chemotherapy orders for VHA oncology services. COMS interfaced and interacted with existing VHA clinical systems, modules and processes within CPRS and VistA database to provide one interface for entering information regarding the provision of oncology services to a patient.