Development of a core outcome set for breast cancer-related lymphedema: a Delphi study

Purpose: For breast cancer survivors (BCS) living with breast cancer-related lymphedema (BCRL), what outcome domains (OD) should be measured to assess the burden of the disease and efficacy of interventions? A Core Outcome Set (COS) that promotes standardized measurement of outcomes within the constraints of time influenced by work environments is essential for patients and the multidisciplinary professionals that manage and research BCRL. Methods: Using Delphi methodology, a multidisciplinary group of BCRL experts (physical and occupational therapists, physicians, researchers, physical therapist assistants, nurses, and massage therapist) completed two waves of online surveys. BCRL expert respondents that completed the first survey (n = 78) had an average of 26.5 years in practice, whereas, respondents who completed the second survey (n = 33) had an average of 24.9 years. ODs were included in the COS when consensus thresholds, ranging from 70% to 80%, were met. Results: A total of 12 ODs made up the COS. Reaching a minimum consensus of 70%; volume, tissue consistency, pain, patient-reported upper quadrant function, patient-reported health-related quality of life, and upper extremity activity and motor control were recommended at different phases of the BCRL continuum in a time-constrained environment. Joint function, flexibility, strength, sensation, mobility and balance, and fatigue met an 80% consensus to be added when time and resources were not constrained. Conclusion: The COS developed in this study thoroughly captures the burden of BCRL. Using this COS may reduce selective reporting, inconsistency in clinical use, and variability of reporting across interdisciplinary healthcare fields, which manage or research BCRL.