Background: Pain is one of cancer patients' most frequent and distressing symptoms; however, analgesics' side effects often increase symptom burden. Further, with the home rapidly becoming the primary cancer care setting, family caregivers (FCs) commonly play central roles in patients' pain self-management, but with little or no preparation. One US-tested intervention, the PRO-SELF© Plus Pain Control Program (PCP), designed to support cancer outpatients and their FCs in pain self-management, is currently being tested in the Swiss multi-centre PEINCA study.