Content development for the functional assessment of cancer therapy-multiple myeloma (FACT-MM): Use of qualitative and quantitative methods for scale construction

Context: Multiple myeloma (MM) is a common hematologic malignancy and is associated with symptom burden and impairments in health-related quality of life (HRQL). Objectives: To develop a disease-specific, patient-reported outcome (PRO) measure for the assessment of HRQL among patients with MM as part of the Functional Assessment of Cancer Therapy (FACT) measurement system. Methods: HRQL concerns and symptoms associated with MM were tabulated based on a literature review, and 52 candidate PRO items were identified. Expert clinicians (n = 13) rated 52 items on relevance to HRQL for MM patients (0-3 scale). Experts added 11 items for comprehensive PRO assessment in MM. A list of 63 candidate items was rated (0-3 scale) by 13 MM patients enrolled through the International Myeloma Foundation website. Qualitative data and quantitative item ratings were reviewed to select FACT-MM scale items. Results: Expert clinicians provided the highest HRQL relevance ratings for bone pain, bodily pain, difficulty walking (2.9), tiring easily (2.6), feeling discouraged (2.5), interference with activities and difficulty with self-care as a result of bone pain (2.5), and fatigue (2.5). Mean age of patients was 57 years; Eastern Cooperative Oncology Group performance status was 0 (38%), 1 (31%), or 2 (31%). Quantitative ratings by patients identified sexual function (1.3), uncertainty about health (1.2), fatigue (1.0), weight gain (1.0), and emotional concerns, such as worry about new symptoms and difficulty planning for the future (1.0) as most relevant to HRQL. Conclusion: The 14-item FACT-MM PRO measure was developed based on expert clinician and patient data, ensuring relevance to HRQL for MM patients.