Depression and long-term mortality among 5-year breast cancer survivors in Korea - a retrospective population-based cohort study

Sep 22, 2026

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The study examines how depression after breast cancer diagnosis relates to long-term mortality risk in a Korean population cohort. Using retrospective population-based cohort data from South Korea’s National Health Insurance Service cancer patient database, researchers included women aged 40+ diagnosed with breast cancer from 2007–2013, who survived at least 5 years and had no depression history before diagnosis. Depression was defined by hospitalization for over 2 days with primary depression diagnosis (ICD-10 F32–F33). Over follow-up, new-onset depression showed higher risks of all-cause and non-cancer mortality, especially in patients aged 65+, supporting screening and treatment needs.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

Methods

Data source

Study design and participants

Depression definition

Outcomes and statistical analysis

[www. nature.com/scientificreports](www. nature.com/scientificreports) OPEN Depression and long-term mortality among 5-year breast cancer survivors in Korea: a retrospective population-based cohort study Su Kyoung Lee1,4, Sangwoo Park2,4 & Sang Min Park2,3􀀍 To examine the association of depression after breast cancer diagnosis with long-term mortality risk in a Korean cohort. We conducted a retrospective population-based cohort study using data from the National Health Insurance Service (NHIS) cancer patient’s cohort of South Korea. We included women aged 40 years or older who were diagnosed with breast cancer between 2007 and 2013, survived at least 5 years, and had no history of depression prior to the breast cancer diagnosis. Depression was defined as hospitalization for more than 2 days with a primary diagnosis of depression (ICD-10 codes F32–F33). We evaluated all-cause, cancer-specific, and non-cancer-specific mortality using the Cox proportional hazards model while adjusting for covariates. Among 30,873 eligible women (mean age, 56.5 years), 502 were diagnosed with new-onset depression during the 5-year survival period, whereas 30,371 did not develop depression. During follow-up after the 5-year survivor period, a total of 1,904 deaths occurred. New-onset depression was associated with higher risks of all-cause mortality (adjusted hazard ratio [aHR], 1.38; 95% CI, 1.03–1.86; p = 0.033) and non-cancer mortality (aHR, 1.81; 95% CI, 1.14–2.86; p = 0.011), while no significant association was observed for cancer-specific mortality. The association was particularly pronounced among patients aged 65 years or older (aHR, 1.96; 95% CI, 1.27–3.03; p = 0.002). Depression was linked to increased mortality among 5-year breast cancer survivors, especially for non-cancer causes. This study implies the need for depression screening and treatment among breast cancer patients, especially in non-Western settings where depression may be underdiagnosed and undertreated. Keywords Breast cancer, Depression, Mortality, Cohort study, Korea Women with breast cancer have to cope with many difficulties that affect their quality of life in both psychological and physical aspects, as they face various sources of stress, fear, and emotional distress related to their condition, treatment options, and outcomes1,2. Depression is one of the most common mental health problems among breast cancer patients, affecting up to 40% of them at some point during or after their treatment3. Depression can have negative impacts on the quality of life, adherence to treatment, and survival outcomes of breast cancer patients4,5. The mechanisms by which depression influences breast cancer survival are complex and multifactorial, involving both behavioral and biological pathways6,7. Depression has been associated with impaired immune function, increased inflammation, changes in hormonal levels, and the potential to impact cytokine homeostasis, consequently enhancing angiogenesis and metastasis8. Moreover, depression may reduce the likelihood of receiving guideline-recommended treatment, which can affect survival7. Substantial evidence gathered from observational and clinical studies strongly indicates a link between the simultaneous occurrence of depression and poorer survival outcomes among women diagnosed with breast cancer, as noted across short-and long-term follow-ups4,9, 10. However, previous research has presented conflicting 1Department of Healthcare Management, College of Health and Medical Science, Daejeon University, Daejeon, Republic of Korea. 2Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Republic of Korea. 3Department of Family Medicine, Seoul National University Hospital, Seoul, Republic of Korea. 4Su Kyoung Lee and Sangwoo Park contributed equally to this work. 􀀍 email: [smpark.snuh@gmail.com](smpark.snuh@gmail.com) [www. nature.com/scientificreports/](www. nature.com/scientificreports/) outco

FAQs

How was depression defined in the study?

Depression was defined as hospitalization for more than 2 days with a primary diagnosis of depression using ICD-10 codes F32–F33.

What outcomes did the researchers analyze?

The study evaluated all-cause mortality, cancer-specific mortality, and non-cancer-specific mortality using a Cox proportional hazards model adjusted for covariates.

Did depression after diagnosis increase mortality risk among 5-year breast cancer survivors?

Yes. New-onset depression was associated with higher risks of all-cause mortality and non-cancer mortality, while no significant association was observed for cancer-specific mortality.

Sep 22, 2026

Upload by Finn