Suicide and violent deaths in survivors of cancer in childhood, adolescence and young adulthood-A national cohort study

Abstract

Suicide risk in adult cancer patients is found to be elevated, but limited information exists regarding risks of suicide and non-suicidal violent deaths when diagnosed with cancer in young age. We investigate suicide and violent deaths in a national cohort including individuals diagnosed with cancer before age 25. Through the linkage of different national registries (Cancer Registry of Norway, Norwegian Causes of Death Registry and the National Registry) a cohort of all live births in Norway during 1965-1985 was defined and followed up through 2008. Individuals diagnosed with cancer before age 25 and the cancer-free references were compared using an extended Cox proportional hazard regression model. The cohort comprised 1,218,013 individuals, including 5,440 diagnosed with cancer before age 25. We identified 24 suicides and 14 non-suicidal violent deaths in the cancer group. The hazard ratio (HR) of suicide in the cancer group was 2.5 (95% confidence interval (CI) 1.7-3.8), and was increased both when diagnosed with cancer in childhood (0-14 years of age); HR = 2.3 (95% CI: 1.2-4.6), and during adolescence/young adulthood (15-24 years); HR = 2.6 (95% CI: 1.5-4.2). Survivors of bone/soft tissue sarcomas, CNS tumors and testicular cancer were at particular risk. The risk of non-suicidal violent death was not increased in the cancer survivors (HR = 1.0; 95% CI: 0.6-1.7). Although based on small numbers and the absolute risk of suicide being low, these are novel findings with important implications for establishing adequate follow-up including suicide prevention strategies for young cancer survivors.