The incidence rate of cancer in patients with schizophrenia: A meta-analysis of cohort studies

Background Numerous studies report that cancer prevalence in patients with schizophrenia might be different from the general population, but findings remain controversial. Aim Our updated meta-analysis of cohort studies aims to analyze the data from cohort studies concerning the incidence risk of overall cancer and some site-specific cancers in patients with schizophrenia. Method We performed a systemic search through electronic databases. Cohort studies evaluating and describing the cancer incidence among patients with schizophrenia were included. Pooled risk ratios (RRs) were calculated for assessing the incidence risk of cancer. Results There were 16 cohort studies included in this meta-analysis, which combined a total of 480,356 participants with schizophrenia and 41,999 cases of cancer. Results showed that there was a slight significant decreased overall risk ratio of cancer incidence among patients with schizophrenia (RR = 0.90, 95% CI 0.81–0.99). When stratified by cancer site and gender, there were significant decreased incidence risk rates of colorectal cancer (RR = 0.82, 95% CI 0.69–0.98) and prostate cancer (RR = 0.55, 95% CI 0.42–0.71) in those patients, moreover, the incidence rate of colorectal cancer decreased significantly in male patients (RR = 0.89, 95% CI 0.81–0.98), and the incidence rate of lung cancer increased significantly in female patients (RR = 1.12, 95% CI 1.01–1.25). Conclusions The incidence risk of some cancers was reduced in patients with schizophrenia. Gender and type of cancer were two important confounding factors contributed to the heterogeneity that required adjustment in our cancer incidence meta-analysis.