Mortality of site-specific cancer in patients with schizophrenia: a systematic review and meta-analysis

Background: Numerous studies have reported contradicting results on the relationship between cancer mortality and schizophrenia. Our aim is to quantify the mortality rate of common site-specific cancers among patients with schizophrenia and to synthesize the available research evidence. Methods: We performed a systemic search of the PubMed, EMBASE and Web of Science databases. Studies reporting the mortality rate of different cancer in patients with schizophrenia were included. A random-effects model was applied to calculate the pooled relative risks (RRs) with 95% confidence intervals (95%CIs). Results: Seven studies consisting of 1,162,971 participants with schizophrenia were included in this meta-analysis. Data regarding mortality risk of breast, colon, lung and prostate cancer among schizophrenia patients were subjected to quantitative analysis. Pooled results showed significant increases in mortality risk of breast cancer (RR = 1.97, 95%CI 1.38-2.83), lung cancer (RR = 1.93, 95%CI 1.46-2.54) and colon cancer (RR = 1.69, 95%CI 1.60-1.80) in patients with schizophrenia compared with those in the general population or control group. The mortality risk of prostate cancer increased in male patients, although no significant difference was detected (RR = 1.58, 95% CI 0.79-3.15). Increased risks of mortality from lung and colon cancer were observed in female patients (RR = 2.49, 95%CI 2.40-2.59 and RR = 2.42, 95%CI 1.39-4.22, respectively) and elevated risks of mortality from lung and colon cancer in male patients (RR = 2.40, 95%CI 2.30-2.50 and RR = 1.90, 95%CI 1.71-2.11, respectively) were detected. Conclusions: Individuals with schizophrenia have a significantly high risk of mortality from breast, colon, and lung cancer.