Aspects of medical history and exocrine carcinoma of the pancreas: a population-based case-control study in The Netherlands

Cancer risk following surgical removal of tonsils and adenoids - a population-based, sibling-controlled cohort study in Sweden

BACKGROUND

Removal of tonsils and adenoids is among the most common surgical procedures worldwide. Evidence of increased risk of cancer following such surgery is, however, inconclusive.

METHODS

We conducted a population-based, sibling-controlled cohort study of 4,953,583 individuals in Sweden with a follow-up during 1980-2016. History of tonsillectomy, adenotonsillectomy, and adenoidectomy was identified from the Swedish Patient Register whereas incident cases of cancer during follow-up were identified from the Swedish Cancer Register. We used Cox models to calculate hazard ratios (HR) with 95% confidence intervals (CI) of cancer in both a population and a sibling comparison. The sibling comparison was used to assess the potential impact of familial confounding, due to shared genetic or non-genetic factors within a family.

RESULTS

We found a modestly increased risk for any cancer following tonsillectomy, adenoidectomy, or adenotonsillectomy in both the population (HR 1.10; 95%CI 1.07-1.12) and sibling (HR 1.15; 95%CI 1.10-1.20) comparisons. The association did not differ greatly by type of surgery, age at surgery, or potential indication for surgery, and persisted more than two decades after surgery. An excess risk was consistently observed for cancer of the breast, prostate, thyroid, and for lymphoma in both population and sibling comparisons. A positive association was observed for pancreatic cancer, kidney cancer, and leukemia in the population comparison whereas a positive association was observed for esophageal cancer in the sibling comparison.

CONCLUSIONS

Surgical removal of tonsils and adenoids is associated with a modestly increased risk of cancer during the decades following the surgery. The association is unlikely attributed to confounding due to shared genetic or non-genetic factors with a family.

Eosinophilic esophagitis-associated epithelial remodeling may limit esophageal carcinogenesis

Introduction

Under homeostatic conditions, esophageal epithelium displays a proliferation/differentiation gradient that is generated as proliferative basal cells give rise to suprabasal cells then terminally differentiated superficial cells. This proliferation/differentiation gradient is often perturbed in esophageal pathologies. Basal cell hyperplasia may occur in patients with gastroesophageal reflux disease (GERD), a condition in which acid from the stomach enters the esophagus, or eosinophilic esophagitis (EoE), an emerging form of food allergy. While GERD is a primary risk factor for esophageal cancer, epidemiological data suggests that EoE patients do not develop esophageal cancer.

Methods

In order to investigate the impact of EoE and esophageal cancer specifically on the cellular landscape of esophageal epithelium, we perform single cell RNA-sequencing in murine models of EoE and esophageal cancer, specifically esophageal squamous cell carcinoma (ESCC). We further evaluate modules of co-expressed genes in EoE- and ESCC-enriched epithelial cell clusters. Finally, we pair EoE and ESCC murine models to examine the functional relationship between these pathologies.

Results

In mice with either EoE or ESCC, we find expansion of cell populations as compared to normal esophageal epithelium. In mice with EoE, we detect distinct expansion of 4 suprabasal populations coupled with depletion of 2 basal populations. By contrast, mice with ESCC display unique expansion of 2 basal populations and 1 suprabasal population, as well as depletion of 2 suprabasal populations. Senescence, glucocorticoid receptor signaling, and granulocyte-macrophage colony-stimulating factor pathways are associated with EoE-enriched clusters while pathways associated with cell proliferation and metabolism are identified in ESCC-enriched clusters. Finally, our in vivo data demonstrate that exposure to EoE inflammation limits tumor burden of esophageal carcinogenesis.

Discussion

Our findings provide the first functional investigation of the relationship between EoE and esophageal cancer and suggest that esophageal epithelial remodeling events occurring in response to EoE inflammation may limit esophageal carcinogenesis. This investigation may have future implications for leveraging allergic inflammation-associated alterations in epithelial biology to prevent and/or treat esophageal cancer.

Noncutaneous and Cutaneous Cancer Risk in Patients With Atopic Dermatitis: A Systematic Review and Meta-analysis

Importance

Impaired skin barrier and aberrant immune function in atopic dermatitis (AD) may alter immune response to malignant cancer. Conflicting data exist on the risk of cancer in patients with AD.

Objective

To assess the risk of noncutaneous and cutaneous cancers in patients with AD compared with the general population without AD.

Data Sources

Studies identified from searches of MEDLINE and Embase that were published from 1946 and 1980, respectively, to January 3, 2019. The following search terms were used: [(exp NEOPLASMS/ OR neoplas*.tw. OR tumo*.tw. OR cancer*.tw. OR malignanc*.tw.) AND (exp Dermatitis, Atopic/ OR (atopic adj1 (dermatit* or neurodermatit*)).tw. OR eczema.tw. OR disseminated OR neurodermatit*.tw.)].

Study Selection

Included were observational studies (cohort and case-control designs) reporting a risk estimate for cancer in patients with AD compared with a control group (general population or patients without AD).

Data Extraction and Synthesis

Two independent reviewers extracted data and assessed the risk of bias using the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) assessment tool, modified for observational exposure studies. Data were pooled using a random-effects model and expressed as standardized incidence ratios (SIRs) or odds ratios (ORs) with 95% CIs. Heterogeneity was assessed using the Cochrane Q statistic and the I2 statistic.

Main Outcomes and Measures

The main outcome of the study was risk of cancer measured by SIRs or ORs.

Results

This systematic review and meta-analysis included 8 population-based cohort studies (n = 5 726 692 participants) and 48 case-control studies (n = 114 136 participants). Among cohort studies, a statistically significant association was found between AD and keratinocyte carcinoma (5 studies; pooled SIR, 1.46; 95% CI, 1.20-1.77) as well as cancers of the kidney (2 studies; pooled SIR, 1.86; 95% CI, 1.14-3.04), central nervous system (2 studies; pooled SIR, 1.81; 95% CI, 1.22-2.70), and pancreas (1 study; SIR, 1.90; 95% CI, 1.03-3.50). Among 48 case-control studies, pooled effects showed patients with AD had statistically significantly lower odds of central nervous system cancers (15 studies; pooled OR, 0.76; 95% CI, 0.70-0.82) and pancreatic cancer (5 studies; pooled OR, 0.81; 95% CI, 0.66-0.98), contrary to the higher incidence found in cohort studies. Case-control studies also demonstrated lower odds of lung and respiratory system cancers (4 studies; pooled OR, 0.61; 95% CI, 0.45-0.82). No evidence of association was found between AD and other cancer types, including melanoma. There was substantial heterogeneity between studies for many other cancers, which precluded pooling of data, and there was moderate to serious risk of bias among included studies.

Conclusions and Relevance

Observational evidence suggests potential associations between AD and increased risk of keratinocyte carcinoma and kidney cancer as well as lower odds of lung and respiratory system cancers. Further research is needed to address the heterogeneity and limitations of current evidence and to better understand the mechanisms underlying a possible association between AD and cancer risk.

Comorbidities in Dermatology: What's Real and What's Not

Comorbidities affecting dermatologic patients are of significant importance to providers and highly relevant for appropriate patient counseling, screening practices, prevention, and treatment. This article seeks to highlight several of the newest findings in the literature regarding comorbidities associated with dermatologic diseases including atopic dermatitis, hidradenitis suppurativa, alopecia areata, chronic urticaria, and the pemphigus family of immunobullous diseases. Further investigation is needed for associations between atopic dermatitis and pancreatic cancer and pemphigus family diseases and chronic obstructive pulmonary disease in order to better characterize the strength of these associations and clinical relevance.

Pancreatic Cancer Following Acute Pancreatitis: A Population-based Matched Cohort Study

BACKGROUND

Acute pancreatitis is linked to pancreatic cancer, but the direction of this association is not fully elaborated.

METHODS

This was a population-based cohort study including all Swedish residents diagnosed with a first-time episode of acute pancreatitis between 1997 and 2013 and corresponding matched pancreatitis-free individuals from the general population. Hazard ratios for the association between acute pancreatitis and pancreatic cancer were estimated using multivariable Cox regression models.

RESULTS

Overall, 49,749 individuals with acute pancreatitis and 138,750 matched individuals without acute pancreatitis were followed up for 1,192,134 person-years (median 5.3 years). A total of 769 individuals developed pancreatic cancer, of whom 536 (69.7%) had a history of acute pancreatitis. The risk of pancreatic cancer was substantially increased during the first few years after a diagnosis of acute pancreatitis but declined gradually over time, reaching a level comparable to the pancreatitis-free population after >10 years of follow-up. In those with non-gallstone-related acute pancreatitis, the risk of pancreatic cancer declined to a level comparable to the pancreatitis-free population only when follow-up time was censored for a second episode of acute pancreatitis or a diagnosis of chronic pancreatitis. Increasing number of recurrent episodes of acute pancreatitis was associated with increased risk of pancreatic cancer.

CONCLUSION

These findings imply a delay in the diagnosis of pre-existing pancreatic cancer, if clinically presented as acute pancreatitis. Any association between non-gallstone-related acute pancreatitis and pancreatic cancer in the long-term (>10 years) could be mediated through recurrent acute pancreatitis or chronic pancreatitis.

Gallstone, cholecystectomy and risk of gastric cancer

Backgrounds/Aims

The aim of this retrospective study is to compare stomach cancer incidence, characteristics between gallstones, cholecystectomy and control groups. It also aims to investigate key variables' potential effects on overall survival.

Methods

A total of 99 patients, diagnosed with stomach cancers between April 1994 and December 2015, were identified. We excluded stomach cancer patients, accrued during the first year of follow-up in both the gallstones and cholecystectomy groups, assuming that they missed cancers. The main analyses addressing the objective were a chi-square analysis and a survival analysis.

Results

The incidence of stomach cancers was increased in both the gallstone and cholecystectomy groups, compared with the control group (p=0.003). Multivariate regression analysis showed that the overall survival in gallstones, cholecystectomy group patients as compared with those in the control group decreased (HR=6.66, 95 CI: 1.94–22.80, p=0.003). Also, T-stage was found to statistically affect the rate of overall survival (HR=9.85, 95% CI: 3.09–31.39, p=.000). The stomach cancer showed the worse survival at the posterior, greater curvature location than anterior, lesser curvature of the stomach. (HR=0.30, 95% CI: 0.11–0.80, p=0.017).

Conclusions

We provided an awareness of the possible increased risks of stomach cancer in gallstone and cholecystectomy group patients, which might be induced by duodenogastric bile reflux. Also, the survival rate was poor (p<0.000). Therefore, close follow-up strategies for early detection are recommended for such patients.

Activated Natural Killer Cells Mediate the Suppressive Effect of Interleukin-4 on Tumor Development via STAT6 Activation in an Atopic Condition Melanoma Model

A protective effect of allergy for cancer has been suggested, but the results are somewhat conflicting, and the mechanism remains elusive. Interleukin-4 (IL-4) signaling has been identified as a potentially important pathway in the development of allergies and the suppression of cancer development. To evaluate the allergy responses in IL-4–mediated tumor development, we compared the growth of B16F10 melanoma cells in 4% phthalic anhydride (PA)-treated IL-4/Luc/CNS-1 transgenic mice (IL-4 mice) and acetone-olive oil (AOO)–treated IL-4 mice as a control for 3 weeks. Much higher allergic responses and natural killer (NK) and STAT6 activation were found in PA-treated IL-4 mice compared with AOO-treated IL-4 control mice. Tumor volume and weight showed an inverse association with the higher allergic response and were significantly reduced in the PA-treated IL-4 mice when compared with those of AOO-treated IL-4 control mice. Significantly higher activation of STAT6, as well as IL-4 and NK cell activation, was found in the tumor tissues of PA-treated IL-4 mice. Infiltration of immune cells and cytokine levels were also higher in the tumor tissues of PA-treated IL-4 mice. We further found that IL-4–activated NK-92MI cells showed increased anticancer effects in human melanoma cells. Overall, these results showed that allergy responses further accelerated the IL-4–induced inhibition of tumor development through the activation of STAT6 pathways.

Reduced risk of pancreatic cancer associated with asthma and nasal allergies

OBJECTIVE

Studies indicate an inverse association between ductal adenocarcinoma of the pancreas (PDAC) and nasal allergies. However, controversial findings are reported for the association with asthma. Understanding PDAC risk factors will help us to implement appropriate strategies to prevent, treat and diagnose this cancer. This study assessed and characterised the association between PDAC and asthma and corroborated existing reports regarding the association between allergies and PDAC risk.

DESIGN

Information about asthma and allergies was collated from 1297 PDAC cases and 1024 controls included in the PanGenEU case-control study. Associations between PDAC and atopic diseases were studied using multilevel logistic regression analysis. Meta-analyses of association studies on these diseases and PDAC risk were performed applying random-effects model.

RESULTS

Asthma was associated with lower risk of PDAC (OR 0.64, 95% CI 0.47 to 0.88), particularly long-standing asthma (>=17 years, OR 0.39, 95% CI 0.24 to 0.65). Meta-analysis of 10 case-control studies sustained our results (metaOR 0.73, 95% CI 0.59 to 0.89). Nasal allergies and related symptoms were associated with lower risk of PDAC (OR 0.66, 95% CI 0.52 to 0.83 and OR 0.59, 95% CI 0.46 to 0.77, respectively). These results were supported by a meta-analysis of nasal allergy studies (metaOR 0.6, 95% CI 0.5 to 0.72). Skin allergies were not associated with PDAC risk.

CONCLUSIONS

This study shows a consistent inverse association between PDAC and asthma and nasal allergies, supporting the notion that atopic diseases are associated with reduced cancer risk. These results point to the involvement of immune and/or inflammatory factors that may either foster or restrain pancreas carcinogenesis warranting further research to understand the molecular mechanisms driving this association.

Genetically Determined Chronic Pancreatitis but not Alcoholic Pancreatitis Is a Strong Risk Factor for Pancreatic Cancer

OBJECTIVE

To study if chronic pancreatitis (CP) is a risk factor for pancreatic cancer.

METHODS

Through a cohort and a case-control study design, CP and other important risk factors including smoking, diabetes, alcohol, obesity, and genetic mutations were studied for their association with pancreatic cancer.

RESULTS

In the cohort study, 402 patients with CP were included. During 3967.74 person-years of exposure, 5 of the 402 patients (4 idiopathic CP, 1 hereditary CP) developed pancreatic cancer after 16.60 ± 3.51 years of CP. The standardized incidence ratio was 121. In the case-control study, 249 pancreatic cancer patients and 1000 healthy controls were included. Of the 249 patients with pancreatic cancer, 24 had underlying idiopathic CP, and none had alcoholic pancreatitis. SPINK1 gene mutation was present in 16 of 26 patients with idiopathic CP who had pancreatic cancer. Multivariable analysis showed CP (odds ratio [OR], 97.67; 95% confidence interval [CI], 12.69-751.36), diabetes (>4 years duration) (OR, 3.05; 95% CI, 1.79-5.18), smoking (OR, 1.93; 95% CI, 1.38-2.69) as significant risk factors for pancreatic cancer. The population attributable risk was 9.41, 9.06, and 9.50 for diabetes, CP, and smoking, respectively.

CONCLUSIONS

Genetically determined CP but not alcoholic CP is a strong risk factor for pancreatic cancer.

Modifiable and non-modifiable risk factors for pancreatic cancer: A review

Pancreatic ductal adenocarcinoma is associated with a poor prognosis and a high case-fatality rate. The reasons for poor prognosis are low rates of curative resection due to local infiltration and distant metastasis. To increase survival rates of patients with pancreatic cancer, early detection through surveillance and screening is important. However, screening could only be cost-effective in high-risk populations. Identification of significant risk factors therefore assumes significance. Risk factors could be non-modifiable or modifiable. Non-modifiable risk factors include increasing age, familial cancer syndromes, Afro-American race, hereditary and other forms of chronic pancreatitis, diabetes, and non-O blood group. Important modifiable risk factors include smoking, obesity, dietary factors such as non-vegetarian diet, and toxins. Preventive strategies at the population level and an effective screening program targeted at high-risk people may help in prevention and early detection of pancreatic ductal adenocarcinoma.

High risk factors of pancreatic carcinoma

Over the past decades, cancer has become one of the toughest challenges for health professionals. The epidemiologists are increasingly directing their research efforts on various malignant tumor worldwide. Of note, incidence of cancers is on the rise more quickly in developed countries. Indeed, great endeavors have to be made in the control of the life-threatening disease. As we know it, pancreatic cancer (PC) is a malignant disease with the worst prognosis. While little is known about the etiology of the PC and measures to prevent the condition, so far, a number of risk factors have been identified. Genetic factors, pre-malignant lesions, predisposing diseases and exogenous factors have been found to be linked to PC. Genetic susceptibility was observed in 10% of PC cases, including inherited PC syndromes and familial PC. However, in the remaining 90%, their PC might be caused by genetic factors in combination with environmental factors. Nonetheless, the exact mechanism of the two kinds of factors, endogenous and exogenous, working together to cause PC remains poorly understood. The fact that most pancreatic neoplasms are diagnosed at an incurable stage of the disease highlights the need to identify risk factors and to understand their contribution to carcinogenesis. This article reviews the high risk factors contributing to the development of PC, to provide information for clinicians and epidemiologists.

Increased Risk of Pancreatic Cancer Related to Gallstones and Cholecystectomy: A Systematic Review and Meta-Analysis

To investigate the potential roles of gallstones and cholecystectomy in pancreatic carcinogenesis, we performed the first meta-analysis of all currently published studies by pooling relative risks (RRs) with 95% confidence intervals (95% CIs). Stratified analysis by ethnicity, study design, and common adjusted factors were also conducted. Individuals with a history of gallstones and cholecystectomy were at increased risk of pancreatic cancer (RR, 1.39; 95% CI, 1.28-1.52; P < 0.001). Gallstones and cholecystectomy were also associated with an elevated risk of pancreatic cancer, respectively (for gallstones: RR, 1.70; 95% CI, 1.30-2.21; P < 0.001; for cholecystectomy: RR, 1.31; 95% CI, 1.19-1.43; P < 0.001). The positive association is observed among not only the Asian population but also whites. The pooled findings were further confirmed by sensitivity analysis and stratified analyses in case-control and cohort studies. Stratified analyses by different adjusted factors further showed that the increased risk of pancreatic cancer was independent of confounders including diabetes, obesity, smoking, and follow-up years of postcholecystectomy. A history of gallstones and cholecystectomy is a robust risk factor for pancreatic cancer. Gallstone disease or cholecystectomy alone is also an independent risk factor for pancreatic carcinogenesis.

Long-Term Diabetes Mellitus Is Associated with an Increased Risk of Pancreatic Cancer: A Meta-Analysis

Purpose

Previous studies have shown a bidirectional relationship between diabetes and pancreatic cancer (PC). In particular, new-onset diabetes might be induced by PC, and people with long-term diabetes might be at increased risk for the development of PC. The purpose of our study was to examine whether long-term diabetes represented an independent risk factor for PC development.

Methodology

A literature search was performed by searching electronic databases for studies published before July 1, 2014, and relative risks (RRs) and corresponding 95% confidence intervals (CIs) were calculated. Data pertaining to diabetes were recorded at both individual and study levels, with RRs calculated separately to analyze the relationship between the duration of diabetes and the development of PC.

Results

Forty-four studies were included in this meta-analysis, including 18 studies with a case-control design, 5 with a nested case-control design and 21 with a cohort design. The overall summary estimate for the relationship between the population with a duration of diabetes ≥2 years and PC was 1.64 (1.52-1.78). The pooled RR (95% CI) of PC for the population with a duration of diabetes ≥5 years was 1.58 (1.42-1.75). For the population with a duration of diabetes ≥10 years, the RR (95% CI) of PC was 1.50 (1.28-1.75).

Conclusions

Our study suggests that long-term diabetes mellitus is associated with an increased risk of PC. However, the level of risk is negatively correlated with increasing diabetes mellitus duration.

Cholecystectomy and the risk of alimentary tract cancers: A systematic review

AIM: To investigate the association between cholecystectomy and gastro-intestinal tract (GIT) cancers.

METHODS: We conducted a systematic review according to the PRISMA guidelines. A MEDLINE search was performed with predefined search criteria for English Language articles on the association between cholecystectomy and GIT cancers. Additional articles were retrieved by manual search of references. All relevant articles were accessed in full text. Data on study type; cases; controls; country; effect estimate; adjustments for confounders and quality of publication were extracted. The quality of the publications were scored by adherence to the STROBE checklist. The data for each part of the GIT were presented in separate tables.

RESULTS: Seventy-five studies and 5 meta-analyses satisfied the predefined criteria for inclusion and were included in this review. There were inconsistent reports and no strong evidence of an association between cholecystectomy and cancers of the oesophagus (Adenocarcinoma), pancreas, small bowel and right-sided colon cancers. In squamous cancer of the oesophagus, cancers of the stomach, liver, bile ducts, small bowel and left sided colon cancers, good quality studies suggested a lack of association with cholecystectomy. Equally, distal colon and rectal cancers were found not to be associated with cholecystectomy. Several mechanisms for carcinogenesis/promotion of carcinogensis have been proposed. These have focused on a role for bile salts in carcinogenesis with several potential mutagenic molecular events and gut metabolic hormones signaling cell proliferation or initiation of carcinogenesis.

CONCLUSION: This is a comprehensive review of the association between GIT cancers and cholecystectomy. This review found no clear association between cholecystectomy and GIT cancers.

Association between pancreatitis and subsequent risk of pancreatic cancer: a systematic review of epidemiological studies

This study aimed to summarize published epidemiological evidence for the relationship between pancreatitis and subsequent risk of pancreatic cancer (PC). We searched Medline and Embase for epidemiological studies published by February 5th, 2014 examining the risk of PC in pancreatitis patients using highly inclusive algorithms. Information about first author, year of publication, country of study, recruitment period, type of pancreatitis, study design, sample size, source of controls and attained age of subjects were extracted by two researchers and Stata 11.0 was used to perform the statistical analyses and examine publication bias. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with the random effects model. A total of 17 articles documenting 3 cohort and 14 case-control studies containing 14,667 PC cases and 17,587 pancreatitis cases were included in this study. The pooled OR between pancreatitis and PC risk was 7.05 (95%CI: 6.42-7.75). However, the pooled ORs of case-control and cohort studies were 4.62 (95%CI: 4.08-5.22) and 16.3 (95%CI: 14.3-18.6) respectively. The risk of PC was the highest in patients with chronic pancreatitis (pooled OR=10.35; 95%CI: 9.13-11.75), followed by unspecified type of pancreatitis (pooled OR=6.41; 95%CI: 4.93-8.34), both acute and chronic pancreatitis (pooled OR=6.13; 95%CI: 5.00-7.52), and acute pancreatitis (pooled OR=2.12; 95%CI: 1.59-2.83). The pooled OR of PC in pancreatitis cases diagnosed within 1 year was the highest (pooled OR=23.3; 95%CI: 14.0-38.9); and the risk in subjects diagnosed with pancreatitis for no less than 2, 5 and 10 years were 3.03 (95%CI: 2.41-3.81), 2.82 (95%CI: 2.12-3.76) and 2.25 (95%CI: 1.59-3.19) respectively. Pancreatitis, especially chronic pancreatitis, was associated with a significantly increased risk of PC; and the risk decreased with increasing duration since diagnosis of pancreatitis.

CARING (CAncer Risk and INsulin analoGues): the association of diabetes mellitus and cancer risk with focus on possible determinants - a systematic review and a meta-analysis

Background:

Patients suffering from diabetes mellitus (DM) may experience an increased risk of cancer; however, it is not certain whether this effect is due to diabetes per se.

Objective:

To examine the association between DM and cancers by a systematic review and meta-analysis according to the PRISMA guidelines.

Data Sources:

The systematic literature search includes Medline at PubMed, Embase, Cinahl, Bibliotek.dk, Cochrane library, Web of Science and SveMed+ with the search terms: “Diabetes mellitus”, “Neoplasms”, and “Risk of cancer”.

Study Eligibility Criteria:

The included studies compared the risk of cancer in diabetic patients versus non-diabetic patients. All types of observational study designs were included.

Results:

Diabetes patients were at a substantially increased risk of liver (RR=2.1), and pancreas (RR=2.2) cancer. Modestly elevated significant risks were also found for ovary (RR=1.2), breast (RR=1.1), cervix (RR=1.3), endometrial (RR=1.4), several digestive tract (RR=1.1-1.5), kidney (RR=1.4), and bladder cancer (RR=1.1). The findings were similar for men and women, and unrelated to study design. Meta-regression analyses showed limited effect modification of body mass index, and possible effect modification of age, gender, with some influence of study characteristics (population source, cancer- and diabetes ascertainment).

Limitations:

Publication bias seemed to be present. Only published data were used in the analyses.

Conclusions:

The systematic review and meta-analysis confirm the previous results of increased cancer risk in diabetes and extend this to additional cancer sites. Physicians in contact with patients with diabetes should be aware that diabetes patients are at an increased risk of cancer.

Cholecystectomy, gallstones, tonsillectomy, and pancreatic cancer risk: a population-based case-control study in Minnesota

Background:

Associations between medical conditions and pancreatic cancer risk are controversial and are thus evaluated in a study conducted during 1994–1998 in Minnesota.

Methods:

Cases (n=215) were ascertained from hospitals in the metropolitan area of the Twin Cities and the Mayo Clinic. Controls (n=676) were randomly selected from the general population and frequency matched to cases by age and sex. The history of medical conditions was gathered with a questionnaire during in-person interviews. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using unconditional logistic regression.

Results:

After adjustment for confounders, subjects who had cholecystectomy or gallstones experienced a significantly higher risk of pancreatic cancer than those who did not (OR (95% CI): 2.11 (1.32–3.35) for cholecystectomy and 1.97 (1.23–3.12) for gallstones), whereas opposite results were observed for tonsillectomy (0.67 (0.48–0.94)). Increased risk associated with cholecystectomy was the greatest when it occurred ⩽2 years before the cancer diagnosis (5.93 (2.36–15.7)) but remained statistically significant when that interval was ⩾20 years (2.27 (1.16–4.32)).

Conclusions:

Cholecystectomy, gallstones, and tonsillectomy were associated with an altered risk of pancreatic cancer. Our study suggests that cholecystectomy increased risk but reverse causality may partially account for high risk associated with recent cholecystectomy.

Association of diabetes mellitus and pancreatic adenocarcinoma: a meta-analysis of 88 studies

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at an advanced, incurable stage. Previous epidemiological data suggests that diabetes mellitus (DM) is a risk factor for PDAC, which may be important in early detection. However, the strength of this association needs to be determined, taking into account a number of recently published studies.

METHODS

A systematic review of the association between DM and PDAC was undertaken by searching electronic databases and journal references from 1973 to 2013. Summary estimates were obtained separately for case-control and cohort studies by means of a 'random effects' approach. Data pertaining to the DM was recorded and plotted at both an individual and study level, with the relative risks (RR) pooled separately to determine the relationship of DM duration and PDAC.

RESULTS

A total of 88 independent studies, including 50 cohort and 39 case-control studies were examined. The overall summary-combined RR was 1.97 (95 % CI 1.78-2.18) with marked heterogeneity that could not be clearly attributed to any subgroup analyses. The risk of PDAC was greatest early after the diagnosis of DM but remained elevated long after the diagnosis. The individual-level RR ranged from 6.69 at less than 1 year to 1.36 at 10 years.

CONCLUSION

The results demonstrate a strong association between PDAC and recently diagnosed DM, which may be attributed to a paraneoplastic effect. However, the presence of diabetes also remains a modest risk factor for the development of PDAC long-term. Selective screening of patients with new-onset DM for PDAC needs to be considered.

Allergies and risk of pancreatic cancer: a pooled analysis from the Pancreatic Cancer Case-Control Consortium

In order to quantify the risk of pancreatic cancer associated with history of any allergy and specific allergies, to investigate differences in the association with risk according to age, gender, smoking status, or body mass index, and to study the influence of age at onset, we pooled data from 10 case-control studies. In total, there were 3,567 cases and 9,145 controls. Study-specific odds ratios and 95% confidence intervals were calculated by using unconditional logistic regression adjusted for age, gender, smoking status, and body mass index. Between-study heterogeneity was assessed by using the Cochran Q statistic. Study-specific odds ratios were pooled by using a random-effects model. The odds ratio for any allergy was 0.79 (95% confidence interval (CI): 0.62, 1.00) with heterogeneity among studies (P < 0.001). Heterogeneity was attributable to one study; with that study excluded, the pooled odds ratio was 0.73 (95% CI: 0.64, 0.84) (Pheterogeneity = 0.23). Hay fever (odds ratio = 0.74, 95% CI: 0.56, 0.96) and allergy to animals (odds ratio = 0.62, 95% CI: 0.41, 0.94) were related to lower risk, while there was no statistically significant association with other allergies or asthma. There were no major differences among subgroups defined by age, gender, smoking status, or body mass index. Older age at onset of allergies was slightly more protective than earlier age.

Ulcer, gastric surgery and pancreatic cancer risk: an analysis from the International Pancreatic Cancer Case-Control Consortium (PanC4)

BACKGROUND

Peptic ulcer and its treatments have been associated to pancreatic cancer risk, although the evidence is inconsistent.

METHODS

We pooled 10 case-control studies within the Pancreatic Cancer Case-control Consortium (PanC4), including 4717 pancreatic cancer cases and 9374 controls, and estimated summary odds ratios (OR) using multivariable logistic regression models.

RESULTS

The OR for pancreatic cancer was 1.10 [95% confidence interval (CI) 0.98-1.23] for history of ulcer (OR = 1.08 for gastric and 0.97 for duodenal ulcer). The association was stronger for a diagnosis within 2 years before cancer diagnosis (OR = 2.43 for peptic, 1.75 for gastric, and 1.98 for duodenal ulcer). The OR was 1.53 (95% CI 1.15-2.03) for history of gastrectomy; however, the excess risk was limited to a gastrectomy within 2 years before cancer diagnosis (OR = 6.18, 95% CI 1.82-20.96), while no significant increased risk was observed for longer time since gastrectomy. No associations were observed for pharmacological treatments for ulcer, such as antacids, H2-receptor antagonists, or proton-pump inhibitors.

CONCLUSIONS

This uniquely large collaborative study does not support the hypothesis that peptic ulcer and its treatment materially affect pancreatic cancer risk. The increased risk for short-term history of ulcer and gastrectomy suggests that any such association is due to increased cancer surveillance.

Is diabetes mellitus a risk factor for pancreatic cancer?

The relationship between diabetes mellitus and the risk of pancreatic cancer has been a matter of study for a long period of time. The importance of this topic is due to two main causes: the possible use of recent onset diabetes as a marker of the disease and, in particular, as a specific marker of pancreatic cancer, and the selection of a population at risk for pancreatic cancer. Thus, we decided to make an in-depth study of this topic; thus, we carried out an extensive literature search in order to re-assess the current knowledge on this topic. Even if diabetes is found a decade before the appearance of pancreatic cancer as reported in meta-analytic studies, we cannot select those patients already having non detectable pancreatic cancer, at least with the imaging and biological techniques available today. We believe that more studies are necessary in order to definitively identify diabetes mellitus as a risk factor for pancreatic cancer taking into consideration that approximately 10 years are needed to diagnose symptomatic pancreatic cancer. At present, the answer to the as to whether diabetes and pancreatic cancer comes first similar to the adage of the chicken and the egg is that diabetes is the egg.

Epidemiological evidence of a relationship between type-1 diabetes mellitus and cancer: a review of the existing literature

This review explores the epidemiological evidence relating to type-1 diabetes (T1DM) and cancer incidence and mortality. Mortality rates among those with T1DM are higher in every age group compared with the general population; the majority of this mortality is due to factors related to the consequences of diabetes, such as cardiovascular and renal disease. For over 100 years, researchers have explored the relationships between diabetes and cancer and although there is now a large body of work on the subject, consensus has not been reached. Such research has tended to focus upon type-2 diabetes, with the result that very little is known about T1DM and cancer. As incidence of T1DM increases, by around 3% annually among children, the need for further research into its impact upon cancer incidence and mortality increases. Within this review, findings varied by study method utilised, T1DM definition used and study region and outcome measure explored. None of the case-control studies found a statistically significant link between the two diseases, whereas both of the meta-analyses did. Cohort studies produced mixed results. There were also mixed findings among research that defined T1DM in the same way (e.g. defining individuals with the disease as those diagnosed with diabetes before 30 years of age). The review found a number of studies which explored cause-specific cancer mortality among those with diabetes; such studies also had mixed findings. This inconsistency within results suggests the need for further research to understand better the potential relationships between T1DM and cancer.

Gastrectomy and risk of pancreatic cancer: systematic review and meta-analysis of observational studies

PURPOSE

To investigate the association between gastrectomy and risk of pancreatic cancer (PaC).

METHODS

We identified eligible studies in Medline and EMBASE up to 11 February 2012 and the reference lists of original studies and review articles on this topic. Summary relative risks with their 95 % confidence intervals were calculated with a random-effects model. Between-study heterogeneity was assessed using Cochran Q and I (2) statistics.

RESULTS

Fifteen studies (11 case-control studies and 4 cohort studies) met eligibility criteria. The current data suggest that gastrectomy is associated with a 54 % excess risk of PaC (SRRs = 1.54; 95 % CI, 1.25-1.90; test for heterogeneity Q = 17.94, p < 0.001, I (2) = 22 %). There was no publication bias in the present meta-analysis.

CONCLUSION

A significant increased risk of PaC exists in patients who have undergone gastrectomy, particularly those receiving Billroth II resection with a long postoperative interval.

Selected medical conditions and risk of pancreatic cancer

We review the current evidence for associations of several medical conditions with risk of pancreatic cancer, including allergies, pancreatitis, gall bladder disease, cholecystectomy, ulcers, gastrectomy, appendectomy, and tonsillectomy. There are consistent findings of reduced risk associated with presence of self-reported allergies, particularly hay fever but not asthma; data on other allergies are limited and inconclusive. Several studies provide evidence that patients with pancreatic cancer are more likely than comparison groups to report pancreatitis. Those studies that investigated the time between onset of pancreatitis and diagnosis of pancreatic cancer found that risk estimates declined with longer periods of time; however, increased risks were noted for long-term pancreatitis, indicating that this condition is both a risk factor and a sign of early disease. Increased risk was reported in association with cholelithiasis, but the few studies that considered time before diagnosis of cancer did not find increased risk for cholelithiasis diagnosed in the more distant past. There is weak evidence that cholecystectomy 2 or more years before cancer diagnosis is related to risk, but this is based on only a few studies. There is no consistent association between ulcers and risk, while gastrectomy may increase risk. Overall, study of these conditions, particularly those that are rare, presents methodologic challenges. Time between diagnoses is likely to be important but is not considered in most studies. Lack of adequate control in several studies for risk factors such as smoking and heavy alcohol use also makes it difficult to draw firm conclusions about these results.

Diabetes and pancreatic cancer

Type 2 diabetes mellitus is likely the third modifiable risk factor for pancreatic cancer after cigarette smoking and obesity. Epidemiological investigations have found that long-term type 2 diabetes mellitus is associated with a 1.5-fold to 2.0-fold increase in the risk of pancreatic cancer. A causal relationship between diabetes and pancreatic cancer is also supported by findings from prediagnostic evaluations of glucose and insulin levels in prospective studies. Insulin resistance and associated hyperglycemia, hyperinsulinemia, and inflammation have been suggested to be the underlying mechanisms contributing to development of diabetes-associated pancreatic cancer. Signaling pathways that regulate the metabolic process also play important roles in cell proliferation and tumor growth. Use of the antidiabetic drug metformin has been associated with reduced risk of pancreatic cancer in diabetics and recognized as an antitumor agent with the potential to prevent and treat this cancer. On the other hand, new-onset diabetes may indicate subclinical pancreatic cancer, and patients with new-onset diabetes may constitute a population in whom pancreatic cancer can be detected early. Biomarkers that help define high-risk individuals for clinical screening for pancreatic cancer are urgently needed. Why pancreatic cancer causes diabetes and how diabetes affects the clinical outcome of pancreatic cancer have yet to be fully determined. Improved understanding of the pathological mechanisms shared by diabetes and pancreatic cancer would be the key to the development of novel preventive and therapeutic strategies for this cancer.

Cholecystectomy and risk of pancreatic cancer: a meta-analysis of observational studies

OBJECTIVE

Data from epidemiological studies related to the association of cholecystectomy and pancreatic cancer (PaC) risk are inconsistent. We conducted a meta-analysis of observational studies to explore this relationship.

METHODS

We identified studies by a literature search of Medline (from 1 January 1966) and EMBASE (from 1 January 1974), through 30 June 2011, and by searching the reference lists of pertinent articles. Summary relative risks with their 95% confidence intervals were calculated with a random-effects model. Between-study heterogeneity was assessed using Cochran's Q statistic and the I (2).

RESULTS

A total of 18 studies (10 case-control studies, eight cohort studies) were included in this meta-analysis. Analysis of these 18 studies found that cholecystectomy was associated with a 23% excess risk of PaC (SRR = 1.23, 95% CI = 1.12-1.35), with moderate heterogeneity among these studies (p (heterogeneity) = 0.006, I (2) = 51.0%). Sub-grouped analyses revealed that the increased risk of PaC was independent of geographic location, gender, study design and confounders. There was no publication bias in the current meta-analysis.

CONCLUSIONS

The results of this meta-analysis suggest that individuals with a history of cholecystectomy may have an increased risk of pancreatic cancer.

Diabetes and pancreatic cancer: chicken or egg?

OBJECTIVES

Although half of all patients with pancreatic cancer are diabetic at the time of diagnosis, it remains unclear whether the diabetes associated with pancreatic cancer is a cause or an effect of the malignancy.

METHODS

Epidemiologic studies were reviewed, the geographic prevalence of diabetes and the incidence of pancreatic cancer were examined, and clinical and laboratory studies were reviewed.

RESULTS

Long-standing diabetes increases the risk of pancreatic cancer by 40% to 100%, and recent-onset diabetes is associated with a 4- to 7-fold increase in risk, such that 1% to 2% of patients with recent-onset diabetes will develop pancreatic cancer within 3 years. Treatment of diabetes or morbid obesity decreases the risk of pancreatic cancer, and metformin therapy decreases the risk due to both its antidiabetic and antineoplastic effects. Recent-onset diabetes associated with pancreatic cancer likely represents secondary or type 3 diabetes. The discrimination of type 3 diabetes from the more prevalent type 2 diabetes may identify the high-risk subgroup of diabetic patients in whom potentially curable pancreatic cancer may be found.

CONCLUSIONS

Type 2 and type 1 diabetes mellitus increase the risk of pancreatic cancer with a latency period of more than 5 years. Type 3 diabetes mellitus is an effect, and therefore a harbinger, of pancreatic cancer in at least 30% of patients.

Italian consensus guidelines for chronic pancreatitis

This paper gives practical guidelines for diagnosis and treatment of chronic pancreatitis. Statements have been elaborated by working teams of experts, by searching for and analysing the literature, and submitted to a consensus process by using a Delphi modified procedure. The statements report recommendations on clinical and nutritional approach, assessment of pancreatic function, treatment of exocrine pancreatic failure and of secondary diabetes, treatment of pain and prevention of painful relapses. Moreover, the role of endoscopy in approaching pancreatic pain, pancreatic stones, duct narrowing and dilation, and complications was considered. Recommendations for most appropriate use of various imaging techniques and of ultrasound endoscopy are reported. Finally, a group of recommendations are addressed to the surgical treatment, with definition of right indications, timing, most appropriate procedures and techniques in different clinical conditions and targets, and clinical and functional outcomes following surgery.

Pancreatic cancer in chronic pancreatitis; aetiology, incidence, and early detection

Acute pancreatitis, chronic pancreatitis and pancreatic cancer are responsible for most of the burden of exocrine pancreatic disease. Glandular damage from recurrent bouts of acute pancreatitis can lead to irreversible changes characteristic of chronic pancreatitis. In recent decades accumulating evidence has defined longstanding pre-existing chronic pancreatitis as a strong risk factor for pancreatic cancer. The lag period between diagnosis of chronic pancreatitis and pancreatic cancer is usually one or two decades: pancreatitis appearing a year or two before the diagnosis of pancreatic cancer is often the result of tumour-related ductal obstruction. The risk of developing pancreatic cancer appears to be highest in rare types of pancreatitis with an early onset, such as hereditary pancreatitis and tropical pancreatitis. Even though there is a strong link between chronic pancreatitis and pancreatic cancer, over a 20 year period only around five percent of patients with chronic pancreatitis will develop pancreatic cancer. Until the development of more sophisticated screening procedures, screening is not recommended for patients with chronic pancreatitis.

Past medical history and pancreatic cancer risk: Results from a multicenter case-control study

PURPOSE

To investigate risk factors that may be linked to pancreatic cancer.

METHODS

We designed a multicenter population-based case-control (823 cases, 1679 control patients) study with data collection by using a common protocol and questionnaire. Participating centers were located in Australia, Canada, the Netherlands, and Poland.

RESULTS

After adjustment for confounding factors, a positive history of pancreatitis was associated with pancreatic cancer (odds ratio [OR], 4.68; 95% confidence interval [95% CI], 2.23-9.84). The risk was especially high in heavy smokers (OR, 15.4; 95% CI, 3.18-74.9). Patients with diabetes had an increased risk of developing pancreatic cancer (OR, 2.16; 95% CI, 1.60-2.91). The risk was highest in the first year after the development of diabetes (OR, 6.68; 95% CI, 3.56-12.6) and decreased over time. A history of allergy was associated with a reduced risk of pancreas cancer (OR, 0.64; 95% CI, 0.50-0.82).

CONCLUSIONS

Patients with newly diagnosed diabetes and patients with pancreatitis, particularly in heavy smokers, have an increased risk for developing pancreatic cancer. In addition to being risk factors, these conditions could be early manifestations of underlying pancreatic cancer. A history of allergy decreases the risk of pancreatic cancer.

History of peptic ulcer disease and pancreatic cancer risk in men

BACKGROUND & AIMS

Peptic ulcer disease has been associated with an increased risk of pancreatic cancer, but findings on this topic are inconsistent. We investigated the association between pancreatic cancer and the occurrence of gastric or duodenal ulcer in a large US cohort.

METHODS

We analyzed data collected from 51,529 male health professionals in a prospective cohort study. History of peptic ulcer disease was assessed at baseline in 1986 and updated biennially thereafter. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models adjusting for smoking, body mass index, diabetes, and physical activity.

RESULTS

During 18 years of follow-up evaluation, we observed 274 incident pancreatic cancer cases. Compared with those with report of no peptic ulcer disease, men with gastric ulcer had an increased risk of pancreatic cancer (RR, 1.83; 95% CI, 1.13-2.97). Although the risk was highest for those with a diagnosis of gastric ulcer that was close in time to the cancer diagnosis (RR, 3.66; 95% CI, 1.45-9.24), the risk remained significantly increased 10-19 years after the gastric ulcer diagnosis (RR, 2.89; 95% CI, 1.26-6.64). In contrast, duodenal ulcer was not associated with pancreatic cancer risk (RR, 1.15; 95% CI, 0.78-1.71).

CONCLUSIONS

Gastric ulcer increases the risk of pancreatic cancer, whereas there does not appear to be an association between duodenal ulcers and pancreatic cancer.

Pancreatitis and pancreatic cancer in two large pooled case-control studies

Objective

The association between duration of pancreatitis and pancreatic cancer has not been well characterized in large population-based studies. We conducted detailed analyses to determine the association between pancreatitis onset and pancreatic cancer risk.

Methods

Data from two case–control studies of pancreatic cancer (n = 4515) in the San Francisco Bay Area and the M.D. Anderson Cancer Center were pooled for analysis (1,663 cases, 2,852 frequency-matched controls). Adjusted odds ratios (OR) were estimated using a random-effects model.

Results

In the pooled multivariable model, history of pancreatitis was associated with a 7.2-fold increased risk estimate for pancreatic cancer [95% confidence interval (CI): 4.0, 13]. The risk estimate was nearly 10-fold in participants aged <55 years (OR = 9.9, 95% CI: 3.5, 28). A shorter temporal history of pancreatitis was more closely associated with pancreatic cancer than was a longer temporal history: <3 years (OR = 29, 95% CI: 12, 71), 3–10 years (OR = 2.6, 95% CI: 1.5, 5.6), and >10 years (OR = 1.8, 95% CI: 0.7, 4.5, p_trend < 0.001).

Conclusion

A short temporal history of pancreatitis was highly associated with pancreatic cancer, suggesting that pancreatitis may be an early manifestation of pancreatic cancer in some individuals. Pancreatic cancer should be considered in the differential diagnosis of individuals with an episode of pancreatitis.

Pancreatic cancer: a review of the evidence on causation

Pancreatic cancer kills more than 250,000 people each year worldwide and has a poor prognosis. The aim of this article is to critically review the epidemiologic evidence for exposures that may either increase or decrease the risk. A Medline search was performed for epidemiologic studies and reviews published up to April 2007. Consistent evidence of a positive association was found for family history and cigarette smoking. Many studies documented a positive association with diabetes mellitus and chronic pancreatitis, although the etiologic mechanisms are unclear. Other associations were detected, but the results were either inconsistent or from few studies. These included positive associations with red meat, sugar, fat, body mass index, gallstones, and Helicobacter pylori, and protective effects of increasing parity, dietary folate, aspirin, and statins. There was no evidence linking alcohol or coffee consumption with an increased risk of pancreatic cancer. The associations with many exposures need to be clarified from further epidemiologic work in which there is both precise measurement of risk factors, adjustment for potential confounders, and, for dietary studies, information recorded on the method of food preparation and pattern of consumption. Such work is important to reduce the incidence of this fatal disease.

Pancreatic cancer-associated diabetes mellitus: prevalence and temporal association with diagnosis of cancer

BACKGROUND & AIMS

The temporal association between diabetes mellitus and pancreatic cancer is poorly understood. We compared temporal patterns in diabetes prevalence in pancreatic cancer and controls.

METHODS

We reviewed the medical records of pancreatic cancer cases residing within 120 miles or less of Rochester, Minnesota, seen at the Mayo Clinic between January 15, 1981, and July 9, 2004, and approximately 2 matched controls/case residing locally. We abstracted all outpatient fasting blood glucose (FBG) levels for up to 60 months before index (ie, date of cancer diagnosis for cases) and grouped them into 12-month intervals; 736 cases and 1875 controls had 1 or more outpatient FBG levels in the medical record. Diabetes was defined as any FBG level of 126 mg/dL or greater or treatment for diabetes, and was defined as new onset when criteria for diabetes were first met 24 or fewer months before index, with at least 1 prior FBG level less than 126 mg/dL.

RESULTS

A higher proportion of pancreatic cancer cases compared with controls met the criteria for diabetes at any time in the 60 months before index (40.2% vs 19.2%, P < .0001). The proportions were similar in the -60 to -48 (P = .76) and -48 to -36 (P = .06) month time periods; however, a greater proportion of cases than controls met criteria for diabetes in the -36 to -24 (P = .04), -24 to -12 (P < .001), and -12 to 0 (P < .001) month time periods. Diabetes was more often new onset in cases vs controls (52.3% vs 23.6%, P < .0001).

CONCLUSIONS

Diabetes has a high (40%) prevalence in pancreatic cancer and frequently is new onset. Identification of a specific biomarker for pancreatic cancer-induced diabetes may allow screening for pancreatic cancer in new-onset diabetes.

Allergies, variants in IL-4 and IL-4R alpha genes, and risk of pancreatic cancer

BACKGROUND

Several studies in epidemiology indicate that risk of pancreatic cancer is reduced in individuals with allergies. Although genes have been identified that are critical in allergic response, polymorphisms in these genes have not been studied in relation to risk of pancreatic cancer. We hypothesized that variants in these genes are related to risk.

METHODS

We investigated the association of allergies and pancreatic cancer in a hospital-based case-control study with 405 cases and 212 controls. In a subgroup of 149 cases and 135 controls, we studied the association of variants in IL-4 (C-589T, G3017T) and IL-4R alpha (Gln576Arg) with allergies and with risk of pancreatic cancer.

RESULTS

We found reduced risk of pancreatic cancer associated with allergies, with adjusted odds ratios of 0.58 (95% CI 0.40-0.84) for any allergies, 0.45 (95% CI 0.29-0.70) for hay fever, and 0.43 (95% CI 0.23-0.80) for animals. The minor allele at each locus studied was associated with reduced risk of allergies in controls, leading us to hypothesize that they would be associated with increased risk of pancreatic cancer. Overall, there was no association between the genotypes studied and risk of pancreatic cancer. In analyses within strata defined by presence or absence of allergies, there were differences in risk associated with genotype for IL-4 G3017T: there was slightly increased risk among those with allergies and reduced risk among those without allergies.

CONCLUSIONS

The consistent association of allergies with risk of pancreatic cancer and these results suggest that associations between variants in genes related to allergic response and pancreatic cancer warrant further study.

The association between allergies and cancer: what is currently known?

OBJECTIVE

To provide an overview of what is currently known about the relationship between allergies and cancer.

DATA SOURCES

Publications were selected from a systematic review of the English-language literature from established databases (eg, MEDLINE, EBSCO) and the references of materials identified through these databases.

STUDY SELECTION

Publications assessing the association between asthma, hay fever, or other allergy-related diseases and cancer were included in this review.

RESULTS

Individuals with any type of allergy have a decreased risk for cancer (compared with the general population), including glioma, colorectal cancer, cancer of the larynx, non-Hodgkin lymphoma, cancer of the esophagus, oral cancer, pancreatic cancer, stomach cancer, and uterine body cancer. However, an increased risk for bladder cancer, lymphoma, myeloma, and prostate cancer exists among those with allergies. Studies that involve breast cancer, leukemia, lung cancer, melanoma, and thyroid cancer have shown no association or conflicting results related to allergies. More research is needed before conclusions can be made about the relation between allergies and Kaposi sarcoma, liver cancer, and cancer of the ovaries.

CONCLUSIONS

The association between allergies and cancer is site specific. Further research is needed to verify these results and to determine why such associations exist.

Pancreatic cancer and medical history in a population-based case-control study in the San Francisco Bay Area, California

OBJECTIVE

To determine the association between pancreatic cancer and medical conditions.

METHODS

A large population-based case-control study identified pancreatic cancer cases in the San Francisco Bay Area between 1995 and 1999. A total of 1,701 controls were randomly selected from the same population and were frequency-matched to 532 cases by sex and age. In-person interviews were conducted with no proxy interviews.

RESULTS

Prior history of gallbladder disease was associated with increased risk of pancreatic cancer (OR = 1.6, 95% CI = 1.2-2.2), with the highest risk occurring for gallbladder disease not caused by cholelithiasis (OR = 2.1, 95% CI = 1.1-3.7). Risk was associated with cholelithiasis only for participants diagnosed within the year before their pancreatic cancer (OR = 15, 95% CI = 6.2-34), and for those with cholelithiasis and cholecystectomy within the same time frame (OR = 28, 95% CI = 8.2-96). Gastric and/or duodenal ulcers were associated with increased risk of pancreatic cancer for individuals with ulcers of <or=two years duration (OR = 2.3, 95% CI = 1.1-4.6). Hyperthyroidism (OR = 2.1, 95% CI = 1.0-4.2) and "other" thyroid conditions (OR = 2.2, 95% CI = 1.1-4.2) were associated with increased risk. Participants with at least one first-degree relative with pancreatic cancer had an increased risk (OR = 1.6, 95% CI = 1.1-2.5).

CONCLUSION

History of recent gallbladder conditions, gastric and/or duodenal ulcers may represent an early manifestation of pancreatic cancer rather than an independent risk factor. These results warrant further investigation in pooled analyses.

The risk of pancreatic cancer in patients with gastric or duodenal ulcer disease

Although Helicobacter pylori (H. pylori) seropositivity is linked to an excess risk of pancreatic cancer, the biologic mechanism is unknown. Gastric ulcer is primarily associated with corpus colonization of H. pylori, atrophic gastritis and formation of N-nitrosamines. Duodenal ulcer is a marker of antral colonization, hyperacidity and uninhibited secretin release. We estimated relative risks for pancreatic cancer among patients with gastric or duodenal ulcer, based on a register-based retrospective cohort study with 88,338 patients hospitalized for gastric ulcer and 70,516 patients for duodenal ulcer recorded in the Swedish Inpatient Register between 1965 and 2003. Following operation, the 14,887 patients who underwent gastric resection and 8,205 with vagotomy were analyzed separately. Multiple record-linkages allowed complete follow-up and identification of all incident cases of pancreatic cancer until December 31, 2003. Standardized incidence ratios (SIRs) estimated relative risks. During years 3-38 of follow-up, we observed a 20% excess risk (95% confidence interval [CI] 10-40%) for pancreatic cancer among unoperated gastric ulcer patients. The excess increased to 50% (95% CI 10-110%) 15 years after first hospitalization (p for trend = 0.03). SIR was 2.1 (95% CI 1.4-3.1) 20 years after gastric resection. Unoperated duodenal ulcer was not associated with pancreatic cancer risk, nor was vagotomy. Our results lend indirect support to the nitrosamine hypothesis, but not to the hyperacidity hypothesis in the etiology of pancreatic cancer.

Pancreatic cancer in type 1 and young-onset diabetes: systematic review and meta-analysis

We conducted a systematic review of the risk of pancreatic cancer in people with type I and young-onset diabetes. In three cohort and six case–control studies, the relative risk for pancreatic cancer in people with (vs without) diabetes was 2.00 (95% confidence interval 1.37–3.01) based on 39 cases with diabetes.

Diabetes mellitus and pancreatic cancer in a population-based case-control study in the San Francisco Bay Area, California

BACKGROUND

Diabetes has been postulated to be both a risk factor and a consequence of pancreatic cancer, but the degree of risk and associated clinical factors remain unclear.

METHODS

We conducted a population-based case-control study of pancreatic cancer in the San Francisco Bay Area between 1995 and 1999. Rapid case ascertainment through the Surveillance, Epidemiology and End Results registry for cases and random selection from the general population for controls were employed to identify study participants with no proxy interviews.

RESULTS

Five hundred thirty-two cases and 1,701 controls were interviewed. Participants with pancreatic cancer were more likely to report a history of diabetes (13%) than were controls [9%; odds ratio (OR), 1.5; 95% confidence interval (95% CI), 1.1-2.1]. Compared with diabetics in the control group, diabetics in the case group had a shorter duration of diabetes (P = 0.0003) and a larger proportion of insulin users (P = 0.002). Risk for pancreatic cancer varied with duration of diabetes (OR, 2.4; 95% CI, 1.4-4.0 for 1-4 years; OR, 2.0; 95% CI, 1.2-3.4 for 5-9 years; and OR, 0.86; 95% CI, 0.52-1.4 for >or=10 years diabetes duration; P(trend) = 0.004). Among diabetics, use of oral diabetes medication or insulin for >or=5 years was not associated with pancreatic cancer, but insulin use of <5 years was associated with a 6.8-fold risk for pancreatic cancer (95% CI, 3.7-12).

CONCLUSION

Recent-onset diabetes may be a complication or an early marker of pancreatic cancer. Diabetes of short duration with insulin use conferred a substantially elevated risk for pancreatic cancer and may reflect insulin resistance that is elicited by pancreatic cancer.

Cigarette smoking, elevated fasting serum glucose, and risk of pancreatic cancer in Korean men

Pancreatic cancer is one of the most fatal human cancers and continues to be a major unsolved health problem. The goal of this study was to estimate the independent effects and interactions between cigarette smoking and diabetes on the risk of pancreatic cancer in Korean male population. Cigarette smoking and the risk of incidence and death from pancreatic cancer were examined in a 10-year prospective cohort study of 446,407 Korean men aged 40 to 65 years who received health insurance from the National Health Insurance Corporation and who had a medical evaluation in 1992. Relative risks (RR) and 95% confidence intervals (CI) were calculated using a Cox proportional hazards model after adjusting for age, body mass index, exercise and alcohol use. Current smoking was associated with an increased risk of incidence (RR = 1.7, 95% CI = 1.6-1.9) and mortality (RR = 1.6, 95% CI = 1.4-1.7) from pancreatic cancer. The RR for pancreatic cancer increased with both duration and amount of smoking. Diabetes was also associated with an increased risk of both incidence (RR = 1.8, 95% CI = 1.5-2.2) and mortality (RR = 1.7, 95% CI = 1.4-2.1) from pancreatic cancer. There was no interaction between smoking and fasting serum glucose in terms of pancreatic cancer risk. Thus, our prospective study has demonstrated that cigarette smoking and elevated fasting serum glucose are independently associated with an increased risk of pancreatic cancer in a large cohort of Korean males.

Serum cadmium levels in pancreatic cancer patients from the East Nile Delta region of Egypt

The northeast Nile Delta region exhibits a high incidence of early-onset pancreatic cancer. It is well documented that this region has one of the highest levels of pollution in Egypt. Epidemiologic studies have suggested that cadmium, a prevalent pollutant in the northeast Nile Delta region, plays a role in the development of pancreatic cancer.

OBJECTIVE

We aimed to assess serum cadmium levels as markers of exposure in pancreatic cancer patients and noncancer comparison subjects from the same region in Egypt.

DESIGN AND PARTICIPANTS

We assessed serum cadmium levels of 31 newly diagnosed pancreatic cancer patients and 52 hospital comparison subjects from Mansoura, Egypt. EVALUATION/MEASUREMENTS: Serum cadmium levels were measured using a novel immunoassay procedure.

RESULTS

We found a significant difference between the mean serum cadmium levels in patients versus comparison subjects (mean+/-SD, 11.1+/-7.7 ng/mL vs. 7.1+/-5.0 ng/mL, respectively; p=0.012) but not in age, sex, residence, occupation, or smoking status. The odds ratio (OR) for pancreatic cancer risk was significant for serum cadmium level [OR=1.12; 95% confidence interval (CI), 1.04-1.23; p=0.0089] and farming (OR=3.25; 95% CI, 1.03-11.64; p=0.0475) but not for age, sex, residence, or smoking status.

CONCLUSIONS

The results from this pilot study suggest that pancreatic cancer in the East Nile Delta region is significantly associated with high levels of serum cadmium and farming. RELEVANCE TO CLINICAL PRACTICE/PUBLIC HEALTH: Future studies should further investigate the etiologic relationship between cadmium exposure and pancreatic carcinogenesis in cadmium-exposed populations.

Atopic dermatitis and cancer risk

BACKGROUND

Epidemiological studies have provided growing evidence of a link between atopy and cancer risk.

OBJECTIVES

To review the evidence from case-control studies and cohort studies on a possible association between atopic dermatitis (AD) and cancer risk, with particular attention to the case definition of AD.

METHODS

Studies with quantitative data on the association between AD (eczematous disease) and cancer risk were obtained from MEDLINE in combination with a review of cited references.

RESULTS

In 23 publications, AD was implicated in the risk of haematological [childhood leukaemia (n = 3), adult leukaemia (n = 3), non-Hodgkin lymphoma (NHL; n = 4) and different haematological cancers (n = 1)], pancreatic (n = 5), skin (n = 2) and brain malignancies (n = 5). The overall picture of the results of these studies shows that a history of AD may be associated with a decreased risk of pancreatic cancer, brain tumour and childhood leukaemia, although in most instances the findings were not statistically significant. No consistent associations were observed for skin cancer or NHL. The definition of AD had varying quality, and was imprecise in the majority of publications.

CONCLUSIONS

The findings of the epidemiological studies tend to support a lower risk of cancer among persons with a history of AD. Although a more careful definition of AD is needed, these epidemiological studies could provide an estimate of the background cancer risk in patients with AD when the long-term effects of treatments for AD are assessed.

Is atopy a protective or a risk factor for cancer? A review of epidemiological studies

OBJECTIVE

There is an ongoing debate whether there is a link between a history of atopy and cancer risk. The purpose of this paper is to review the published epidemiological studies on the association between atopy and the risk of cancers.

METHODS

Through an electronic search (January 1986-April 2004) with an additional review of cited references, we identified studies with quantitative data on the relation of atopy (irrespective of its definition or subtype) to cancer (different cancer sites).

RESULTS

The protective effect of atopy in colorectal cancer has been observed consistently in the case-control studies, but not in cohort studies. A consistent inverse association between self-reported atopy and glioma risk has been shown, but there is absence of such an association for meningioma. In most studies, the risk of leukaemia, in particular childhood leukaemia, tends to be lower among people with a history of atopy. Studies, which looked at, the association between atopic diseases and risk of cancers of pancreatic, breast, lymphoma showed varying outcomes. Most studies on the atopy-pancreatic cancer relation suggested an inverse association. For lymphoma, most studies have shown no substantial association. Overall evidence indicates an increased risk of lung cancer among persons with a history of asthma.

CONCLUSION

Despite the mixed results, the emerging picture from most of the currently available epidemiological data indicate that atopic disease is associated with a reduced risk for cancer. Further research should focus on a more carefully defined 'atopy' status and manifestation of different atopic diseases, to advance our understanding of the role that allergies might play in the risk of developing cancer.

Allergies and the risk of pancreatic cancer: a meta-analysis with review of epidemiology and biological mechanisms

Previous reports suggest that allergic disorders may protect against various types of cancer, but the association between history of allergy and pancreatic cancer risk has not been well studied. We did a systematic review and meta-analysis of published studies to evaluate the association of any type, and specific types, of allergy and the risk of pancreatic cancer. We did a comprehensive literature search using MEDLINE, PUBMED, and the ISI Web of Science databases to identify potential relevant case-control and cohort studies. Pooled relative risks (RR) and 95% confidence intervals (95% CI) were calculated using the fixed- and random-effects model. Fourteen population-based studies (4 cohort and 10 case-control studies) with a total of 3,040 pancreatic cancer cases fulfilled our inclusion criteria. A history of allergy was associated with a reduced risk of pancreatic cancer (RR, 0.82; 95% CI, 0.68-0.99). The risk reduction was stronger for allergies related to atopy (RR, 0.71; 95% CI, 0.64-0.80), but not for asthma (RR, 1.01; 95% CI, 0.77-1.31). There was no association between allergies related to food or drugs and pancreatic cancer (RR, 1.08; 95% CI, 0.74-1.58). Overall, there was no evidence of publication bias. Allergies, in particular those related to atopy, seem to be associated with a decreased risk of pancreatic cancer. The hyperactive immune system of allergic individuals may, therefore, in some way lead to increased surveillance and protect against pancreatic cancer development.

Type-II diabetes and pancreatic cancer: a meta-analysis of 36 studies

Pancreatic cancer is the eighth major form of cancer-related death worldwide, causing 227 000 deaths annually. Type-II diabetes is widely considered to be associated with pancreatic cancer, but whether this represents a causal or consequential association is unclear. We conducted a meta-analysis to examine this association. A computer-based literature search from 1966 to 2005 yielded 17 case–control and 19 cohort or nested case–control studies with information on 9220 individuals with pancreatic cancer. The age and sex-adjusted odds ratio (OR) for pancreatic cancer associated with type-II diabetes was obtained from each study. The combined summary odds ratio was 1.82 (95% confidence interval (95% CI) 1.66–1.89), with evidence of heterogeneity across the studies (P=0.002 for case–control and P=0.05 for cohort studies) that was explained, in part, by higher risks being reported by smaller studies and studies that reported before 2000. Individuals in whom diabetes had only recently been diagnosed (<4 years) had a 50% greater risk of the malignancy compared with individuals who had diabetes for ⩾5 years (OR 2.1 vs 1.5; P=0.005). These results support a modest causal association between type-II diabetes and pancreatic cancer.

Allergy and the risk of selected digestive and laryngeal neoplasms

The relation between allergy and cancer has been investigated within an integrated series of case-control studies of digestive tract and laryngeal neoplasms conducted in Italy since the early 1990s. These included 598 patients with incident, histologically confirmed cancer of the oral cavity and pharynx, 304 of the oesophagus, 1225 of the colon, 728 of the rectum, 460 of the larynx and 4999 controls, selected among patients admitted to the same network of hospitals as cases for acute, non-neoplastic diseases. Inverse associations with history of allergy were found for all cancer sites examined (odds ratio=0.44 for oral cavity and pharynx, 0.80 for oesophagus, 0.76 for colon, 0.54 for rectum and 0.33 for larynx). The associations were consistent in strata of age and sex, and when subjects with a first diagnosis of allergy 5 or more years before cancer diagnosis or hospital admission were considered. The present study therefore provides further evidence for a possible protective effect of prior history of allergy on cancer risk.