A novel clinical assessment scale for evaluating financial toxicity in breast cancer patients

Background: Although there are existing tools to assess financial toxicity, a comprehensive instrument that evaluates both the objective financial burden and subjective financial distress, while capturing changes in coping mechanisms, is still lacking for breast cancer patients. Therefore, the aim of this study is to develop a specific scale to assess financial toxicity in breast cancer patients and to examine its psychometric properties. Methods: This study was conducted at the First Affiliated Hospital of China Medical University from July 2022 to November 2023 and was approved by the hospital’s Ethics Committee (Approval No. [2022] 456). Participants were purposively sampled from the Breast Surgery Department. Inclusion criteria included: females aged 18 years or older, with a confirmed diagnosis of breast cancer, and meeting at least one of the following conditions: (1) post-surgery for at least 6 months, (2) completion of radiotherapy and/or chemotherapy, or (3) ongoing endocrine or targeted therapy for ≥6 months. Patients with severe organ-related diseases (e.g., heart, brain, liver, kidney) or concurrent cancers were excluded. The development and validation of the scale were carried out in 3 steps: firstly, a preliminary item pool was formed through literature review, and qualitative interviews, and experts were invited to revise and form a pilot scale. Subsequently, an initial scale was formed through item analysis and preliminary exploratory factor analysis. Finally, the reliability and validity of the scale were verified by examining its psychometric properties. Findings: A total of 464 participants were included in the study. Following item analysis and exploration, an initial scale consisting of 20 items was formed from the pilot scale with 29 items. Exploratory factor analysis extracted 3 common factors with a cumulative contribution rate of 54.018%. Confirmatory factor analysis confirmed a good fit of the 3-factor model (X2/df=2.103, RMSEA=0.076, NFI=0.924, GFI=0.929, IFI=0.959, TLI=0.943, CFI=0.958). The construct validity was confirmed by a negative correlation between the self-made scale and the Chinese version of the Comprehensive score for financial toxicity (r=-0.812, P<0.01). The internal consistency coefficient of the scale was 0.887, with internal consistency coefficients of 0.847, 0.690, and 0.857 for each dimension. The test-retest reliability of the scale was r=0.888 (P<0.001). The S-CVI value of the scale was 0.952, and the I-CVI value ranged from 0.8 to 1.0. The final version of the scale consisted of 3 dimensions and 11 items. Interpretation: The developed scale for financial toxicity in breast cancer patients demonstrated good reliability and validity, and can be used to assess the current status of financial toxicity in breast cancer patient populations. However, this study only included patients from the First Affiliated Hospital of China Medical University, which may limit the generalizability of the findings. Future studies should incorporate a more diverse sample to further validate the scale’s applicability across different regions. Funding: None.