Methods: A nested concurrent mixed methods design will be used for this multi-center study, that is, a randomized controlled trial (RCT) will be combined with a qualitative substudy. Participants will be randomly assigned to a 6-week intervention or usual care group; outcomes will be evaluated at 6 weeks post-randomization. The primary outcome will be pain intensity. A total sample of 210 patients with cancer pain and approximately 105 FCs will be recruited from the oncology outpatient clinics of the University Hospitals Basel, Zurich and Bern. The intervention is designed to implement structured and tailored components (information, skill-building, nurse coaching) and aims at improving patients' pain self-management. Data analysis will follow an intent-to-treat strategy and generalized mixed models will be used. For the qualitative substudy, 60 patients and FCs of both groups will be interviewed. Data will be systematically summarized.