Background: The BREAST-Q is a patient-reported outcome measure to evaluate satisfaction and health-related quality of life (HRQOL) after breast surgery. The aim of this study is to test the acceptability, reliability, and validity of the most recently developed BREAST-Q module for breast-conserving therapy (BCT) in a prospective clinical cohort.
Methods: The BREAST-Q BCT module was translated into German according to international guidelines. A total of 253 women with primary breast cancer undergoing BCT were recruited preoperatively. This study evaluated the BREAST-Q BCT subscales by using psychometric methods including acceptability, reliability, and validity. To examine construct validity, convergent and discriminant validity were determined by testing the instrument's scales against the EORTC C30 and BR23 as reference questionnaires.
Results: Acceptability was supported by a high follow-up rate (90%) and low frequency of missing data (< 10%) in all but three scales. Scale reliability was supported by high Cronbach's alpha coefficients (> 0.86) and item-total correlations (range of means, 0.33-0.89). Validity was shown by convergent and divergent correlations. The hypotheses of relationships between the scales of the BREAST-Q and the EORTC QLQ C30 BR23 revealed moderate to high correlations.
Conclusions: The BREAST-Q BCT module proved to be an accepted, reliable, and valid questionnaire for the assessment of HRQOL and patient satisfaction after BCT in breast cancer patients. It can be recommended as a possible standard PROM for individual clinical analysis, quality assessment, and future trials.