BACKGROUND: Uncertainty about the benefits new cancer medicines will deliver in clinical practice risks delaying patient access to new treatment options in countries such as England, where the cost effectiveness of new medicines affects reimbursement decisions. Outcome-based payment (OBP) schemes, whereby the price paid for the drug is linked to patients' real-world treatment outcome(s) has been put forward as a mechanism to accelerate access. Although OBP schemes have generally focused on clinical outcomes to determine reimbursement, the degree to which these represent the outcomes that are important to patients is unclear. OBJECTIVE: To advance the application of OBP we ask, what outcomes do patients with cancer value (most) that might form a practical basis for OBP? METHODS: A review of the literature on outcomes in cancer produced a long list of candidates. These were evaluated in a focus group with patients with cancer and were then, in a second focus group, distilled to a shortlist of ten outcomes using a card sort method. The ten outcomes were included in an online survey of patients with cancer and carers, who were asked to rank the importance of each outcome. RESULTS: The focus groups identified a range of both clinical and functional outcomes that are important to patients. Analyses of the 164 survey responses suggested that the four most important outcomes to patients and carers are survival; progression, relapse or recurrence; post-treatment side effects; and return to normal activities of daily life. CONCLUSION: Commissioners of cancer services wishing to instigate an OBP scheme should prioritise collecting data on these outcomes as they are important to patients. Of these, only mortality data are routinely collected within the national health service (NHS). Progression and some morbidity data exist but are not currently linked, creating a challenge for OBP.