Development and Assessment of the 8-item Chronic Pain Acceptance Questionnaire to Measure Disease Acceptance in Women With Breast Cancer

Study Background and Rationale Breast Cancer (BC) remains a major global health challenge that often leads to long-term psychological distress, body image concerns, and fatigue, even after the completion of medical treatment. Disease acceptance has emerged as a key determinant of positive emotional and functional outcomes. Therefore, reliable and valid instruments are necessary to quantify acceptance in the context of Breast Cancer (BC) for both research and clinical practice. This study addresses the limited availability of disease-specific outcome measures by developing the Cancer Pathology Acceptance Questionnaire for Breast Cancer (CPAQ-8-BC). This instrument is an adaptation of the 8-item Chronic Pain Acceptance Questionnaire (CPAQ-8). The adaptation process involved replacing the words "pain" and "chronic pain" with the terms "tumor" or "disease" to make the instrument context-specific for patients. Methodology and Participants This is a cross-sectional, observational study approved by the University Ethical Review Committee of Sapienza University of Rome (Protocol No. 53-2023). Sample Size: A total of 101 women with a confirmed histopathological diagnosis of Breast Cancer (BC) were consecutively enrolled from two inpatient Hospital Breast Units. Inclusion Criteria: Adult age, confirmed Breast Cancer (BC) diagnosis, and the ability to understand the Italian language. Data Collection: Participants filled out the self-administered Cancer Pathology Acceptance Questionnaire for Breast Cancer (CPAQ-8-BC), which consists of 8 items rated on a scale of 0 (never true) to 6 (always true). A pilot testing phase was conducted to assess the scale's face validity, appropriateness, acceptability, and feasibility. Psychometric Evaluation Plan The primary focus of the psychometric testing is to investigate the Structural Validity, Reliability, and Interpretability of the Cancer Pathology Acceptance Questionnaire for Breast Cancer (CPAQ-8-BC): * Structural Validity: Confirmatory Factor Analysis (CFA) is performed to test a single-factor structure against a pre-hypothesized two-factor structure consisting of Activity Engagement and Disease Receptivity. Model fit is evaluated using the Comparative Fit Index (CFI), Tucker Lewis Index (TLI), Standardized Root Mean Square Residual (SRMR), and Root Mean Square Error of Approximation (RMSEA). * Reliability: Internal consistency is assessed using Cronbach's alpha and McDonald's omega. Test-Retest Stability is investigated using the Intraclass Correlation Coefficient (ICC2,1) over a 10-15 day period. The Standard Error of Measurement (SEM) is also calculated. * Interpretability: The Minimum Detectable Change (MDC) is estimated to determine the smallest change in score that can be considered a true change rather than measurement error. Clinical Relevance The Cancer Pathology Acceptance Questionnaire for Breast Cancer (CPAQ-8-BC) is intended to serve as a tool for person-oriented evaluations in multidisciplinary rehabilitation settings. Identifying patients with low acceptance levels may help clinicians identify those prone to activity avoidance and poor functional recovery. The instrument is designed to support the tailoring of interventions, such as Acceptance and Commitment Therapy (ACT) or Cognitive-Behavioral Therapy (CBT), by assessing key areas of psychological flexibility.