Background: Pain prevalence at various stages of cancer ranges from 27% to 60% for outpatients. Yet, how pain is managed in this patient group is poorly understood. Objectives: The primary objective was to assess pain prevalence and intensity, and its interference with daily activities, in medical oncology outpatients. The secondary objectives were the adequacy of analgesic pain treatment and to identify independent predictors for moderate to severe pain. Study design: A cross-sectional study. Setting: Oncology outpatient clinics of 7 Dutch regional hospitals. Methods: Four hundred twenty-eight medical oncology outpatients were assigned to the study. Pain prevalence and interference of pain with daily activities were assessed using the Brief Pain Inventory. Adequacy of analgesic treatment was determined by calculating the Pain Management Index (PMI). Descriptive statistics, non-parametric tests, and logistic regression analysis were conducted. Results: More than one third of all participants reported pain (39%). Eighty-three patients (20%) had moderate to severe pain (NRS 5-10). Analgesic treatment was inadequate in more than half of the patients with pain (62%). Interference of pain with daily activities increased with increased intensity, yet even 10%-33% of patients suffering mild pain reported high interference with daily activities. High current pain intensity and high interference with general daily activities predicted moderate to severe pain. Limitations: No characteristics of nonparticipants were available. Conclusion: Pain remains a significant problem in medical oncology outpatients, and often pain is insufficiently managed. Patients with a high pain intensity were more at risk to experience pain related interference with daily activities, but even some patients suffering mild pain experienced this. As adequate pain relief for up to 86% of the patients with cancer should be feasible, pain in medical oncology outpatients is still undertreated. Taking into account the interference of pain with daily activities and predictors of pain will facilitate cancer pain management. The study has been approved by the Medical Ethics Committee (CMO) in all 7 hospitals (METC protocol number 2011/020) and has been registered by the Dutch Trial register (NTR): NTR2739. Key words: Pain, prevalence, cancer, interference with daily activities, pain management, Brief Pain Inventory, Pain Management Index, neuropathic pain

Pain in medical oncology outpatients is not systematically registered in their medical records. With one exception, pain was not registered with a VAS or NRS. Yet, registration and assessment of pain to monitor pain are essential to evaluate and adapt pain treatment over time. Pain registration has not improved since 2001 and therefore implementing the recommendations regarding systematic monitoring of pain is needed.