Prospective development of a patient-reported outcomes instrument for desmoid tumors or aggressive fibromatosis

Summary

Desmoid tumors (or aggressive fibromatosis) are locally infiltrative connective-tissue tumors that can arise in any anatomic location; they can be asymptomatic, or they can result in pain, deformity, swelling, and loss of mobility and/or threaten visceral organs with bowel perforation, hydronephrosis, neurovascular damage, and other complications. Existing clinical trial endpoints such as the Response Evaluation Criteria in Solid Tumors (version 1.1) and progression-free survival are inadequate in capturing treatment efficacy. This study was designed to develop a novel clinical trial endpoint by capturing patient-reported outcomes (PROs). Following best practices in qualitative methodology, this study used concept elicitation (CE) interviews to explore desmoid patients' perspectives on key disease-related symptoms and impacts. Qualitative analysis was performed to determine the relative frequency and disturbance of symptoms and impacts as well as other characteristics of these concepts. A draft PRO scale was then developed and tested with cognitive interviewing. Information from the interviews was subsequently incorporated into the refined PRO scale. CE interviews with desmoid patients (n = 31) helped to identify salient concepts and led to a draft scale that included symptom and impact scales. Cognitive interviews were completed with additional patients (n = 15) across 3 phases. Patient input was used to refine instructions, revise and/or remove items, and modify the response scale. This resulted in an 11-item symptom scale and a 17-item impact scale. This is the first disease-specific PRO instrument developed for desmoid tumors.