Cancer characteristics in patients with schizophrenia: a 25-year retrospective analysis

Schizophrenia is associated with higher cancer-related mortality, perhaps due to delayed diagnosis and limited access to treatment. The study aimed to compare patients diagnosed with cancer with and without schizophrenia to determine whether these groups differ in terms of oncological variables and survival outcomes. This was a retrospective, observational cohort study that included 30.990 patients diagnosed with cancer between 1997 and 2021. We performed univariate and bivariate analyses for the sociodemographic and clinical variables, and constructed Kaplan-Meier survival curves and used the log-rank test to perform the comparisons. All variables were compared for each cancer type. One hundred and sixty-two (0.52 %) patients had a confirmed diagnosis of schizophrenia (ICD-9 criteria). The mean age at diagnosis was significantly lower in the schizophrenia group. A significantly higher proportion of the schizophrenia group was diagnosed with cancer through the emergency department and a lower percentage through scheduled appointments. A smaller percentage of patients in the schizophrenia group received radical treatment for cancer. The mortality rate was higher in the schizophrenia group and median survival was lower. These findings suggest that cancer patients with schizophrenia have worse outcomes than patients without schizophrenia in terms of oncological variables and survival.