Medicare’s Oncology Care Model (OCM) is designed to incentivize providers to reduce unnecessary spending, improve care, and involve patients more closely in decisions about the use of chemotherapy. The model includes a 13-point care plan recommended by the Institute of Medicine (IOM) that represents a significant step toward making patients partners in their own care; in particular, it aims the volume of OCM episodes by reducing overly aggressive use of chemotherapy and underuse of hospice services among patients who are close to death. However, IOM recommendations since 1999 and recent medical literature suggest that a formal shared decision-making process (SDM) remains vitally important. This paper discusses the rationale for and barriers to adopting a more formal SDM. We recommend that SDM be added to the OCM in at least a subset of cancers and/or oncology practices before the demonstration program ends in 2021.