Abstract
BACKGROUND: In breast cancer surgery, patient-reported outcome measures are needed to measure outcomes best reported by patients (e.g., psychosocial well-being). This study aimed to develop and validate a new BREAST-Q module to address the unique concerns of patients undergoing breast-conserving therapy (BCT). METHODS: Phase 1 involved qualitative and cognitive interviews with women who had BCT and clinical expert input to establish content for the BCT module. A field-test (phase 2) was performed, and Rasch measurement theory (RMT) analysis was used for item reduction and examination of reliability and validity. Validation of the item-reduced scales in a clinical sample (phase 3) was conducted for further assessment of their psychometric properties. RESULTS: Qualitative interviews with 24 women resulted in the addition of 15 new items across multiple existing BREAST-Q scales and the development of two new scales (Adverse Effects of Radiation and Satisfaction With Information-Radiation Therapy). Feedback from 15 patients and 5 clinical experts were used to refine the instructions, response options, and item wording. An RMT analysis of data from 3497 women resulted in item reduction. The final set of scales showed evidence of ordered response option thresholds, good item fit, and good reliability, except for the Adverse Effects of the Radiation Scale. Validity and reliability were further supported by the phase 3 data from 3125 women. CONCLUSIONS: The BREAST-Q BCT module can be used in research and clinical care to evaluate quality metrics and to compare surgical outcomes across all breast cancer surgery patients.