There is growing recognition that patient-reported outcome (PRO) measures--encompassing, for example, health-related quality of life--can complement traditional biomedical outcome measures (eg, survival, disease-free survival) in conveying important information for cancer care decision making. This paper provides an integrated review and interpretation of how PROs have been defined, measured, and used in a range of recent cancer research and policy initiatives. We focus, in turn, on the role of PRO measurement in the evaluation and approval of cancer therapies, the assessment of cancer care in the community, patient-provider decision making in clinical oncology practice, and population surveillance of cancer patients and survivors. The paper concludes with a discussion of future challenges and opportunities in PRO measure development and application, given the advancing state of the science in cancer outcomes measurement and the evolving needs of cancer decision makers at all levels.