Background: Patients with breakthrough pain in cancer (BTPc) experience impaired activities of daily living and quality of life. Both function and satisfaction with treatment can impact patients' abilities to use products, and likely impact response to therapies.Objective: This exploratory analysis examined the relationship between functional status and satisfaction with ability to use fentanyl pectin nasal spray (FPNS) for BTPc.Methods: Treatment satisfaction data were analyzed from a multicenter, open-label, long-term study using FPNS for managing BTPc in patients with Eastern Cooperative Oncology Group (ECOG) grade ≤ 2. Satisfaction with ease of use, convenience, and reliability of FPNS were assessed on three-question, fourpoint scales (1 = not satisfied, 2 = not satisfied or dissatisfied, 3 = satisfied, 4 = very satisfied) at the end of 1, 4, 8, and 12 weeks. For each domain, percentage of patients who reported being "satisfied or very satisfied" (score 3 or 4) with FPNS was analyzed based on ECOG grade.Results: Overall, > 90 % of patients with ECOG 0-2 reported being satisfied or very satisfied with FPNS across all three domains. Differences in patient satisfaction with FPNS by ECOG grade were clinically small though statistically significant (ease of use: p = 0.0022, convenience: p = 0.0057, and reliability: p = 0.0012).Conclusion: The FPNS device was well accepted irrespective of ECOG grade (0-2). Statistically, patients with higher performance status (lower ECOG grades) reported higher sat-