Reliability and validity of the Dutch bodily threat monitoring scale in breast cancer survivors

Background: Breast cancer survivors (BCS) commonly experience fear of cancer recurrence (FCR), fueling vigilance toward bodily sensations such as pain, which can cause further fear and reduce quality of life. FCR is a primary clinical concern of cancer survivors across countries, and hypervigilance is identified as a core clinical criterion of FCR, but we still do not have great measures for it or understand the subcomponents of it. Therefore, the Bodily Threat Monitoring Scale (BTMS) is a self-report scale designed to capture this vigilance toward bodily sensations as signals of threat. This study evaluates the reliability and construct validity of the BTMS-Dutch. Methods: Adult BCS completed the BTMS and other validated questionnaires of bodily processing, FCR, and health-related quality of life (n = 87); a subsample completed the BTMS again 2 weeks later (n = 67). Reliability was investigated using Cronbach alpha and intraclass correlations. Confirmatory factor analysis was used to inspect assumed subscales. Construct validity was investigated by evaluating correlations with the Illness Attitudes Scale (IAS) and the Anxiety Sensitivity Index (ASI-3). Associations with theoretically related clinical outcomes, specifically FCR and health-related quality of life, were also inspected. Results: The BTMS showed good-to-excellent internal consistency for the total score (α = 0.906) and assumed subscales (bodily monitoring α = 0.855; bodily threat appraisals α = 0.915). The ICC ranged from moderate-to-good (BTMS = 0.811; BM = 0.708; BTA = 0.836), confirming adequate test-retest reliability. The BTMS evidenced good construct validity, demonstrating a strong association with the IAS (r = 0.762) and a moderate association with the ASI-3 (r = 0.442). The two-factor structure of the BTMS did not provide a strong fit. Associations with FCR and indices of health-related quality of life were replicated. Conclusions: The BTMS-Dutch demonstrated good reliability and construct validity, and associations with theoretically related clinical outcomes including FCR were replicated. The two-factor structure could not be confirmed.