Background: A diagnosis of cancer is associated with an increased suicide risk, and this risk is the highest within the first year of diagnosis. The aim of the present study was to determine risk factors of suicide occurring within the first year of cancer diagnosis (early suicide).
Methods: The sampling pool consisted of 164,497 patients with cancer admitted to a general hospital in Seoul, South Korea, from 1996 to 2009. We conducted a 1:2 matched case-control study by matching 373 patients who died from suicide (cases) with 746 patients who did not die from suicide (controls) on age, sex, anatomic site, and at the time of cancer diagnosis. Data were analyzed using Cox proportional hazards regression modeling.
Results: Suicide within the first year after a cancer diagnosis occurred in 149 patients (40.0% of 373 total suicides). The standardized mortality ratio (SMR) for early suicide was 1.65 [95% confidence interval (CI) = 1.40-1.94] and was significantly higher for biliary-pancreatic (SMR = 3.07; 95% CI = 2.02-4.46), lung (SMR = 1.94; 95% CI = 1.19-3.30), and stomach (SMR = 1.71; 95% CI = 1.16-2.42) cancers than for other cancers. Early and late suicide was significantly different in anatomic site (p = 0.01) and stage (p < 0.001), while not significant in other demographic factors. Advanced stage was more frequent among early suicide compared with late suicide (53.4 versus 18.7%; p < 0.001). Stage of cancer was independently associated with early suicide risk.
Conclusions: Cancers with an advanced stage at diagnosis were associated with an increased risk of suicide within 1 year of diagnosis.
Keywords: advanced stage; cancer; clinical factors; early suicide; oncology.
Copyright © 2014 John Wiley & Sons, Ltd.