Abstract PS1-04-07: Sleep, depressive symptoms and quality of life among women with newly diagnosed breast cancer: findings from the AMBER cohort study

Abstract Background: Sleep problems are common among breast cancer survivors and are associated with poor quality of life. Yet, few studies have accounted for depression. This study examines whether depressive symptoms attenuate the association between sleep and quality of life in newly diagnosed breast cancer survivors. Methods: Women with newly diagnosed early-stage breast cancer were recruited between 2012-2019 in Alberta, Canada, and completed the Pittsburgh Sleep Quality Index (PSQI) to assess global sleep quality. Quality of life was measured using the Short Form Survey (SF-36 version-2) to assess physical and mental well-being. Depressive symptoms were measured using the Patient Health Questionnaire (PHQ-9). Multivariable linear regressions were used to estimate the association of sleep measures with physical and mental well-being. Depressive symptoms were evaluated as a potential confounder and effect modifier. Results: Among 1454 breast cancer survivors with available data, 43% reported poor global sleep quality and 10.5% reported clinically meaningful depressive symptoms. Poor sleep quality was associated with lower physical (β=-3.0, 95%CI: -3.8 to -2.3) and mental well-being (β=-5.7, 95%CI: -6.7 to -4.7). These associations were attenuated to (β=-2.3, 95%CI: -3.1 to 1.5) and (β=-1.2, 95%CI: -2.1 to -0.3) after further adjusting for depression symptoms. Stratified analyses showed a slightly stronger association in women with non-minimal symptoms, though this association was not clinically meaningful. Conclusion: The association between sleep and quality of life was substantially attenuated after accounting for depressive symptoms. Longitudinal data are needed to clarify the temporal relationship and determine whether sleep can serve as an early indicator of emerging depression. Next steps: Based on these findings, we are currently investigating depressive symptoms as a mediator for the association between sleep health and quality of life, using longitudinal data collected from time of diagnosis to five-years follow-up. We will be able to complete the analyses and report findings from the mediation analyses at the time of conference. Citation Format: L. Yang, T. Tayyab, R. Kokts-Porietis, Q. Wang, J. McNeil, M. Matthews, L. Dickau, J. Vallance, M. McNeely, N. Culos-Reed, K. Kopciuk, K. Courneya, C. Friedenreich. Sleep, depressive symptoms and quality of life among women with newly diagnosed breast cancer: findings from the AMBER cohort study [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS1-04-07.