Schizophrenia and Cancer: In 2010 Do We Understand the Connection?

Abstract

In recent years, there has been a plethora of cancer mortality and incidence data reported in schizophrenia. Despite this, there has been little focus on cancer in schizophrenia guidelines. Additionally, there have been suggestions that schizophrenia may provide inherent protection against cancer. The goal of this review is to establish, using recent data, the incidence and mortality rates for cancer in schizophrenia. Method: We identified systematic reviews and meta-analyses and undertook a search using the Medical Subject Headings' entry terms schizophrenia and neoplasm. Results: Incidence and mortality rates for cancer in schizophrenia are increased, compared with relevant general populations. Data are not uniformly reported and cohort ages tend to be young for expected cancer incidence. Despite the young cohort ages, the incidence of the major cancers-lung and breast-are substantially increased. Confounders are often not measured in the epidemiologic databases. When lung cancer is adjusted for smoking rates, there appears to be a lower risk of lung cancer than expected providing some basis to support an inherently reduced risk of cancer. There may also be a dissonance between incidence and mortality rates that suggest a prejudice against either diagnosis or treatment of these vulnerable patients. Conclusion: A single definitive study of schizophrenia and cancer is unfeasible, and future research will lean heavily on systematic review and meta-analysis. Researchers should report cancer data to include age and follow-up data and cohort overlap. Cancer accounts for almost an equivalent mortality as cardiovascular disease.

The Characteristics of Nicotine Addiction Among Patients with Schizophrenia

“…Although lung cancer occurs less frequently in patients with schizophrenia than among the general population, the effects of cigarette smoking are clearly seen here [27]. In the case of COPD and lung cancer, cigarette smoking is undoubtedly a significant etiologic factor [28].…”

The Effect of Study Design on the Reporting of Mortality Due to Colorectal Cancer in Adults with Mental Illness in Nova Scotia

“…5,7,8 Support for the former comes from the finding that CRC incidence is also reduced in first-degree relatives of people with schizophrenia. 5,6 However, these findings are not universal. One study 9 reported a significantly elevated risk of CRC in patients with schizophrenia that increased further in patients receiving antipsychotics.…”

“…5 Psychiatric patients may also present later because of reduced access to primary care or cancer screening, and therefore have more advanced disease on diagnosis. [10][11][12] There is little information on access to specialist services following diagnosis.…”

“…5,6 Explanations include genetic factors or protective effects of psychotropics, including antipsychotics and SSRIs. 5,7,8 Support for the former comes from the finding that CRC incidence is also reduced in first-degree relatives of people with schizophrenia. 5,6 However, these findings are not universal.…”

Prolactin and Schizophrenia, an Evolving Relationship

“…Certainly the data on bone fractures (Howard et al, 2007;Abel et al, 2008) has shown us the potential. The World Health Organization (WHO) initiated a number of databases to measure cancer rates in schizophrenia in the 1970s (Bushe and Hodgson, 2010) and have the knowledge and ability to conduct similar projects worldwide relating to outcomes of hyperprolactinaemia. 3.…”