Suicide risk after cancer diagnosis among older adults: A nationwide retrospective cohort study

Objectives
Cancer increases suicide risk, but little is known about associations between cancer and suicide among older adults. We aimed to investigate suicide risk within 1 year after cancer diagnosis in older adults.
Methods
Using National Health Insurance Service-Senior Cohort data, we included newly diagnosed older patients with cancer and older adults without cancer, selected by a 1:3 propensity score matching using sex, age, Charlson comorbidity index, and index year from 2004 to 2012 and followed them up throughout 2013. We used Cox proportional hazard models to estimate adjusted hazard ratios (AHR) of suicide risk.
Results
In the total sample of 259,688 older adults (aged 62–115 years), the highest proportion of observed suicide deaths occurred within one year after cancer diagnosis (36.1% of total); 64,922 older patients with cancer showed higher suicide risk after cancer diagnosis compared to non-cancer participants (AHR 2.05; 95% CI 1.64–2.56). Patients with mental disorder diagnosis before cancer diagnosis (AHR 2.98; 95% CI 2.12–4.18) had increased suicide risk than those without mental disorder diagnosis (AHR 1.78; 95% CI 1.38–2.29) compared to non-cancer participants. Suicide risk among older patients with bladder, head and neck, liver, lung, and stomach cancers was higher than in non-cancer participants (AHR 4.77, 2.28, 2.99, 1.98, 2.40; 95% CI 2.53–8.99, 1.47–3.54, 1.63–5.49, 1.15–3.40, 1.57–2.24), respectively.
Conclusions
Older patients with cancer have a higher suicide risk. Early mental health support needs to be provided with consideration of prediagnosis mental disorders during follow-up after cancer diagnosis.