This paper describes a methodology that engages the clinical community into the design process of creating Clinical Information Systems (CISs) under a Clinical Team-Led Design (CTLD) approach in the context of using Immediately Adaptable (IA) system development technology. The methodology is contrasted against the Enterprise Electronic Medical Record (EEMR) model for usability, efficiency, and adaptability. The methodology was tested in a Breast Cancer setting where the CIS went through 4 rapid agile stages. Time and motion statistics, training times, system changes, and user feedback data was collected for assessment. The results showed that the Breast CIS increased time efficiency by 30% in the first 3 months of implementation. Users reported high usability and trainability of the system. Over 95% of system design change requests were satisfied with an average turn-around time of 3 days. The results show that systems designed under a CTLD approach, accompanied by Immediately Adaptable system architecture, provide greater efficiency for staff in clinical settings while enabling the workflow processes to be adapted dynamically as part of continuous process improvement.