Risk of prostate cancer in patients with schizophrenia

The Risk and The Course of Cancer Among People with Severe Mental Illness

The paucity of data regarding patients with Serious Mental Illness (SMI) and cancer is alarming given the fact that people with SMI, especially schizophrenia, bipolar disorders and severe depressive disorders, have in general poorer access to physical health care and higher morbidity and mortality because of physical illnesses. The aims of this review were to examine the current evidence from existing literature on the risk of developing cancer and its course among people with SMI. Equivocal results emerge regarding the risk of developing some kind of cancer among people with SMI, with contrasting data on a possible higher, similar or lower risk in comparison with the general population. In contrast, a series of studies have pointed out that patients with SMI who develop cancer are less likely to receive standard levels of cancer care, both in terms of screening, diagnosis and treatment. Also, the mortality for cancer has been confirmed to be higher than the general population. A global sensitization about these problems is mandatory in an era in which community psychiatry has been developed in all countries and that policies of prevention, treatment, follow up, and palliative care should regard all the segments of the population, including people with SMI, through an interdisciplinary approach.

Cancer incidence and stage at diagnosis among people with psychotic disorders: Systematic review and meta-analysis

Research regarding the incidence of cancer among people with psychotic disorders relative to the general population is equivocal, although the evidence suggests that they have more advanced stage cancer at diagnosis. We conducted a systematic review and meta-analysis to examine the incidence and stage at diagnosis of cancer among people with, relative to those without, psychotic disorders. We searched the MEDLINE, EMBASE, PsycINFO, and CINAHL databases. Articles were included if they reported the incidence and/or stage at diagnosis of cancer in people with psychotic disorders. Random effects meta-analyses were used to determine risk of cancer and odds of advanced stage cancer at diagnosis in people with psychosis, relative to those without psychotic disorders. A total of 40 articles were included in the review, of which, 31 were included in the meta-analyses. The pooled age-adjusted risk ratio for all cancers in people with psychotic disorders was 1.08 (95% CI: 1.01-1.15), relative to those without psychotic disorders, with significant heterogeneity by cancer site. People with psychotic disorders had a higher incidence of breast, oesophageal, colorectal, testicular, uterine, and cervical cancer, and a lower incidence of skin, prostate, and thyroid cancer. People with psychotic disorders also had 22% higher (95% CI: 2-46%) odds of metastases at diagnosis, compared to those without psychotic disorders. Our systematic review found a significant difference in overall cancer incidence among people diagnosed with psychotic disorders and people with psychotic disorders were more likely to present with advanced stage cancer at diagnosis. This finding may reflect a need for improved access to and uptake of cancer screening for patients diagnosed with psychotic disorders.

The presence of polymorphisms in genes controlling neurotransmitter metabolism and disease prognosis in patients with prostate cancer: a possible link with schizophrenia

Polymorphisms of neurotransmitter metabolism genes were studied in patients with prostate cancer (PC) characterized by either reduced or extended serum prostate-specific antigen doubling time (PSADT) corresponding to unfavorable and favorable disease prognosis respectively. The ‘unfavorable prognosis’ group (40 cases) was defined by PSADT ≤ 2 months, whereas patients in the ‘favorable prognosis’ group (67 cases) had PSADT ≥ 30 months. The following gene polymorphisms known to be associated with neuropsychiatric disorders were investigated: a) the STin2 VNTR in the serotonin transporter SLC6A4 gene; b) the 30-bp VNTR in the monoamine oxidase A MAOA gene; c) the Val158Met polymorphism in the catechol-ortho-methyltransferase COMT gene; d) the promoter region C-521T polymorphism and the 48 VNTR in the third exon of the dopamine receptor DRD4 gene.

The STin2 12R/10R variant of the SLC6A4 gene (OR = 2.278; 95% CI = 0.953–5.444) and the -521T/T homozygosity of the DRD4 gene (OR = 1.579; 95% CI = 0.663–3.761) tended to be overrepresented in PC patients with unfavorable disease prognosis. These gene variants are regarded as protective against schizophrenia, and the observed trend may be directly related to a reduced PC risk described for schizophrenia patients. These results warrant further investigation of the potential role of neurotransmitter metabolism gene polymorphisms in PC pathogenesis.

The overall and sex- and age-group specific incidence rates of cancer in people with schizophrenia: a population-based cohort study

AIMS

Decades of research show that people with schizophrenia have an increased risk of death from cancer; however, the relationship between schizophrenia and cancer incidence remains less clear. This population-based study investigates the incidence of seven common types of cancer among people with a hospital diagnosis of schizophrenia and accounting for the effects of age, sex and calendar time.

METHODS

This population-based study used 1990-2013 data from three nationwide Swedish registries to calculate the incidence (in total, by age group and by sex) of any cancer and of lung, oesophageal, pancreatic, stomach, colon, (in men) prostate and (in women) breast cancer in 111 306 people with a hospital diagnosis of schizophrenia. The incidence in people with diagnosed schizophrenia was compared with the incidence in the general population. Risk estimates accounted for the effects of calendar time.

RESULTS

In 1 424 829 person-years of follow-up, schizophrenia did not confer an overall higher cancer risk (IRR 1.02, 95% CI 0.91-1.13) but was associated with a higher risk for female breast (IRR 1.19, 95% CI 1.12-1.26), lung (IRR 1.42, 95% CI 1.28-1.58), oesophageal (IRR 1.25, 95% CI 1.07-1.46) and pancreatic (IRR 1.10, 95% CI 1.01-1.21) and a lower risk of prostate (IRR 0.66, 95% CI 0.55-0.79) cancer. Some age- and sex-specific differences in risk were observed.

CONCLUSIONS

People with schizophrenia do not have a higher overall incidence of cancer than people in the general population. However, there are significant differences in the risk of specific cancer types overall and by sex calling for efforts to develop disease-specific prevention programmes. In people with schizophrenia, higher risk generally occurs in those <75 years.

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.

Lung cancer incidence in patients with schizophrenia: meta-analysis

BACKGROUND

Lung cancer risk factors, like tobacco smoking, are highly prevalent in patients with schizophrenia. Whether these patients have a higher risk of lung cancer remains unknown.

AIMS

We aimed to investigate whether patients with schizophrenia have a higher incidence of lung cancer compared with general population, in a meta-analysis.

METHOD

Eligible studies were searched from PubMed and EMBASE databases to identify cases of lung cancer in patients with schizophrenia and the general population. This meta-analysis utilised the random-effects model and prediction interval was used to calculate the heterogeneity of these eligible studies. We assessed the quality of evidence with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

There were 12 studies, totalling 496 265 patients, included in this meta-analysis. The data showed that the baseline schizophrenia diagnosis was not associated with any changes in lung cancer incidence in the overall population, with a standardised incidence ratio of 1.11 (95% CI 0.90-1.37; P = 0.31), although there was a significant heterogeneity among these studies (I2 = 94%). Moreover, there was also a substantial between-study variance with wide prediction interval values (0.47-2.64). The data were consistent for both males and females.

CONCLUSIONS

Up-to-date evidence from epidemiological studies indicates the lack of certainty about the association between schizophrenia diagnosis and lung cancer incidence.

Double-Edged Sword of Tumour Suppressor Genes in Schizophrenia

Schizophrenia (SCZ) is a common psychiatric disorder with polygenetic pathogenesis. Among the many identified candidate genes and loci, the group of tumour suppressor genes has drawn our interest. In this mini-review article, we describe evidence of a correlation between major tumour suppressor genes and SCZ development. Genetic mutations ranging from single nucleotide polymorphisms to large structural alterations have been found in tumour-related genes in patients with SCZ. Epigenetic mechanisms, including DNA methylation/acetylation and microRNA regulation of tumour suppressor genes, have also been implicated in SCZ. Beyond genetic correlations, we hope to establish causal relationships between tumour suppressor gene function and SCZ risk. Accumulating evidence shows that tumour suppressor genes may mediate cell survival and neural development, both of which contribute to SCZ aetiology. Moreover, converging intracellular signalling pathways indicate a role of tumour suppressor genes in SCZ pathogenesis. Tumour suppressor gene function may mediate a direct link between neural development and function and psychiatric disorders, including SCZ. A deeper understanding of how neural cell development is affected by tumour suppressors may lead to improved anti-psychotic drugs.

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.

Cancer prevalence in Israeli men and women with schizophrenia

The aim of this cross-sectional study was to compare cancer prevalence rates among patients with schizophrenia to those of the non-schizophrenia population. The study population included members of Clalit Health Services aged 25 to 74 years and all data was taken from patients' electronic health records. Of the 2,060,314 members who were included in the study, 32,748 had a diagnosis of schizophrenia. Cancer prevalence rates in women with and without schizophrenia were 491 per 10,000 and 439 per 10,000, respectively; in men, cancer prevalence rates were 226 per 10,000 and 296 per 10,000, respectively. The age-adjusted prevalence rate of all-type cancer was significantly lower among men with schizophrenia, compared to men without schizophrenia; specifically, men with schizophrenia had a lower rate of prostate cancer, and of cancers in the "other" category, compared to men without schizophrenia. Reduced cancer rates in men with schizophrenia may reflect under-diagnosis of some cancer types, likely due to insufficient medical attention. An effort to improve screening regimes should be made.

Cancer and central nervous system disorders: protocol for an umbrella review of systematic reviews and updated meta-analyses of observational studies

BACKGROUND

The objective of this study will be to synthesize the epidemiological evidence and evaluate the validity of the associations between central nervous system disorders and the risk of developing or dying from cancer.

METHODS/DESIGN

We will perform an umbrella review of systematic reviews and conduct updated meta-analyses of observational studies (cohort and case-control) investigating the association between central nervous system disorders and the risk of developing or dying from any cancer or specific types of cancer. Searches involving PubMed/MEDLINE, EMBASE, SCOPUS and Web of Science will be used to identify systematic reviews and meta-analyses of observational studies. In addition, online databases will be checked for observational studies published outside the time frames of previous reviews. Eligible central nervous system disorders will be Alzheimer's disease, anorexia nervosa, amyotrophic lateral sclerosis, autism spectrum disorders, bipolar disorder, depression, Down's syndrome, epilepsy, Huntington's disease, multiple sclerosis, Parkinson's disease and schizophrenia. The primary outcomes will be cancer incidence and cancer mortality in association with a central nervous system disorder. Secondary outcome measures will be site-specific cancer incidence and mortality, respectively. Two reviewers will independently screen references identified by the literature search, as well as potentially relevant full-text articles. Data will be abstracted, and study quality/risk of bias will be appraised by two reviewers independently. Conflicts at all levels of screening and abstraction will be resolved through discussion. Random-effects meta-analyses of primary observational studies will be conducted where appropriate. Parameters for exploring statistical heterogeneity are pre-specified. The World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) criteria and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be used for determining the quality of evidence for cancer outcomes.

DISCUSSION

Our study will establish the extent of the epidemiological evidence underlying the associations between central nervous system disorders and cancer and will provide a rigorous and updated synthesis of a range of important site-specific cancer outcomes.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016052762.

Prostate cancer and neuroendocrine differentiation: more neuronal, less endocrine?

Neuroendocrine differentiation (NED) marks a structural and functional feature of certain cancers, including prostate cancer (PCa), whereby the malignant tissue contains a significant proportion of cells displaying neuronal, endocrine, or mixed features. NED cells produce, and can secrete, a cocktail of mediators commonly encountered in the nervous system, which may stimulate and coordinate cancer growth. In PCa, NED appears during advanced stages, subsequent to treatment, and accompanies treatment resistance and poor prognosis. However, the term “neuroendocrine” in this context is intrinsically vague. This article seeks to provide a framework on which a unified view of NED might emerge. First, we review the mutually beneficial interplay between PCa and neural structures, mainly supported by cell biology experiments and neurological conditions. Next, we address the correlations between PCa and neural functions, as described in the literature. Based upon the integration of clinical and basic observations, we suggest that it is legitimate to seek for true neural differentiation, or neuromimicry, in cancer progression, most notably in PCa cells exhibiting what is commonly described as NED.

Prostate Cancer Related JAZF1 Gene is Associated with Schizophrenia

BACKGROUND

Epidemiological studies have shown that there is a reduced risk of prostate cancer among persons diagnosed with schizophrenia (SCZ). However, the mechanism of such relationship is not clear. The reduced incidence of cancer observed in SCZ patients may be related to differences in genetic background. Recently, the JAZF1 gene is found to be associated with prostate cancer and type 2 diabetes. However, no study has focused on the association of JAZF1 with the risk of SCZ.

METHODS

We examined genetic associations of 118 single-nucleotide polymorphisms (SNPs) within the JAZF1 gene with SCZ using one European American (EA) sample of 1,149 cases and 1,347 controls. Logistic regression analysis of SCZ as a binary trait was performed using PLINK software.

RESULTS

The most significant association with SCZ was observed with rs10258132 (p = 0.0011); while the next best signal was rs17156259 (p = 0.0031). The third best associated SNP was rs7791865 (p = 0.00889). In addition, haplotype analyses revealed that the A-C haplotype from rs10244184 and rs10258132 was associated with SCZ (p = 0.00093); and the G-G haplotype from rs17156238 and rs17156259 was associated with SCZ (p = 0.00455).

CONCLUSION

These findings provide evidence of several genetic variants in JAZF1 gene influencing the risk of SCZ and will serve as a resource for replication in other populations.