WHEN THE DATA ARE NOT ENOUGH: SHARED MEDICAL DECISION MAKING. A. Rosen 1 ; 1 University of California, San Francisco, CA LEARNING OBJECTIVES: 1) Increase awareness of decision analysis as a tool for shared medical decision making (SMDM), 2) Recognize the importance of patient preferences in making medical decisions. CASE INFORMATION: A 77yo male with paroxysmal atrial fibrillation and recent diagnosis of colon cancer with hepatic metastases presented to my clinic. His quality of life (QOL) and functional status were excellent and he desired no adjuvant chemotherapy unless his QOL significantly worsened. He presented questioning his need for coumadin. We constructed à`b ack-of-the-envelope'' decision tree to address this question.