Risk of prostate cancer in patients with schizophrenia.

ABSTRACT

OBJECTIVES: To examine the rate of prostate cancer in a cohort of schizophrenia in-patients in the PSA-era as compared to expected rates. There is conflicting evidence on the relative risk of prostate cancer in men with schizophrenia. METHODS: the study sample was comprised of schizophrenia patients who had been admitted to a tertiary care mental health center between 1990 and 2011. The data for the sample was cross-referenced with the National Cancer Registry. Analyses of Standardized Incidence Rates (SIR) for prostate cancer and for lung cancer (representing an organ system not sensitive to sex hormones) were performed. RESULTS: Of 4,326 schizophrenia patients included in the present study, 181 (4.2%) were diagnosed with cancer at any site. Only 10 of these patients were diagnosed with prostate cancer. This reflects a reduced risk; SIR of 0.56 (95% CI 0.27-1.03). In the same cohort, 33 schizophrenia patients were diagnosed with lung cancer presenting a SIR of 1.43 (95% CI 0.98-2.01) in this sample. CONCLUSIONS: The present study suggests a reduced rate of prostate cancer in patients admitted for schizophrenia. There are several possible explanations for this finding including chronic state of hyperprolactinemia induced by antipsychotic drugs.