Development and psychometric testing of the lymphedema self-management support scale for breast cancer survivors.

Objective: Effective self-management support should be tailored to the individual. To provide personalized and targeted self-management support, a rigorous assessment tool is needed to screen the actual degree of lymphedema self-management support received by breast cancer survivors. This study aims to develop and psychometrically test the Lymphedema Self-Management Support Scale for Breast Cancer Survivors (LSMS-BCs). Methods: This study involves two phases: scale development and psychometric testing. In the scale development phase, preliminary items and domains were identified through a qualitative meta-synthesis, a quantitative systematic review, and reference to previous similar scales. Expert consultation and pilot study were conducted to refine the scale and evaluate the content validity. The psychometric characteristics were tested with 447 participants using item analysis, exploratory factor analysis (EFA), confirmatory factor analysis (CFA), reliability assessments, as well as measurement invariance. Results: A preliminary 21-item scale with four domains, basic management support, management support for limb volume reduction, role management support, and emotional management support, was constructed in the scale development phase and well supported by EFA and CFA. The scale-level content validity index was 0.983. Cronbach's α coefficient for overall scale and subscales ranged from 0.732 to 0.949. McDonald's ω ranged from 0.848 to 0.955. Excellent known-groups validity, concurrent validity, predictive validity, and measurement invariance were demonstrated. Conclusions: The LSMS-BCs is psychometrically valid and reliable. It can serve as a valuable tool for assessing and understanding the lymphedema self-management support received by breast cancer survivors.