Cancer mortality in patients with psychiatric diagnoses: a higher hazard of cancer death does not lead to a higher cumulative risk of dying from cancer

Both increased as well as decreased cancer mortality among psychiatric patients has been reported, but competing death causes were not included in the analyses. This study aims to investigate whether observed cancer mortality in patients with psychiatric disorders might be biased by competing death causes. In this retrospective cohort study on data from the Psychiatric Case Register Middle Netherlands linked to the death register of Statistics Netherlands, the risk of cancer death among patients with schizophrenia (N = 4,590), bipolar disorder (N = 2,077), depression (N = 15,130) and their matched controls (N = 87,405) was analyzed using a competing risk model. Compared to controls, higher hazards of cancer death were found in patients with schizophrenia (HR = 1.61, 95 % CI 1.26-2.06), bipolar disorder (HR = 1.20, 95 % CI 0.81-1.79) and depression (HR = 1.26, 95 % CI 1.10-1.44). However, the HRs of death due to suicide and other death causes were more elevated. Consequently, among those who died, the 12-year cumulative risk of cancer death was significantly lower. Our analysis shows that, compared to the general population, psychiatric patients are at higher risk of dying from cancer, provided that they survive the much more elevated risks of suicide and other death causes.