Depression risk among breast cancer survivors: a nationwide cohort study in South Korea.

Background: Depression among breast cancer survivors is a significant concern affecting their long-term survivorship and quality of life. This study investigates the incidence of depression among breast cancer survivors and identifies associated risk factors.
Methods: This retrospective cohort study used data from the Korean National Health Insurance Service database and included 59,340 breast cancer patients without a history of depression who underwent surgery between January 1, 2010, and December 31, 2016. They were individually matched 1:2 by age with a general population without cancer (n = 99,834). The mean follow-up period was 6.4 ± 2.6 years. Sub-distribution hazard ratios (sHRs) and 95% confidence intervals (CIs) were calculated considering death as a competing risk and adjusting for sociodemographic factors and comorbidities.
Results: Breast cancer survivors with a mean (standard deviation) age of 51.5 (9.2) years had a 39% increased risk of depression compared to non-cancer controls (sHR 1.39, 95% CI 1.36-1.42). During the first year post-diagnosis, breast cancer survivors across all ages exhibited a significantly elevated risk of depression, with a sHR of 3.23 (95% CI 3.08-3.37). Notably, younger survivors had a sHR of 4.51 (95% CI 4.19-4.85), and older survivors had a sHR of 2.56 (95% CI 2.42-2.71). One year post-surgery, younger survivors (age ≤ 50 years) showed a 1.16-fold increase in depression risk (sHR 1.16, 95% CI 1.11-1.20), while older survivors (age > 50 years) showed no significant change in risk, which decreased over time. Use of anthracycline, taxane, or endocrine therapy was associated with an increased depression risk (sHR 1.17, 95% CI 1.13-1.22; sHR 1.12, 95% CI 1.07-1.16; and sHR 1.27, 95% CI 1.14-1.41, respectively), with endocrine therapy showing a 41% increased depression risk in older survivors (sHR 1.41, 95% CI 1.23-1.61).
Conclusion: This study demonstrates a significant association between breast cancer and depression, with a particularly heightened risk in younger survivors within the first year post-diagnosis. Special attention is needed to meticulously screen for depressive symptoms during the early follow-up years for breast cancer survivors who are premenopausal or have undergone chemotherapy and endocrine therapy.
Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Institutional Review Board of Samsung Medical Center (approval no. NHIS-2023-1-212). The NHIS granted permission to use the NHIS database. Informed consent was waived because all screened populations agreed to transfer their screening results to the NHIS, and the NHIS database was constructed after anonymization of individual identities. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.
(© 2024. The Author(s).)