Body mass index and risk of adenocarcinomas of the esophagus and gastric cardia

Epidemiology of adenocarcinoma of the esophagus, gastric cardia, and upper gastric third

The incidence of adenocarcinoma of the esophagus and esophagogastric junction (gastric cardia) has risen rapidly over the past three decades in the United States and northern Europe. This increase had been most dramatic among White males. The majority of these cancers arise from Barrett's esophagus. However, less than 10% of the patients with esophageal adenocarcinoma were known to have Barrett's esophagus before. Current evidence indicates that gastroesophageal reflux and obesity are major risk factors for adenocarcinoma of the esophagus. Abdominal obesity, more prevalent in males, and independent of body mass index, seems to be associated with an increased risk of esophageal adenocarcinoma but not of cardia adenocarcinoma. This observation may explain the high male:female ratio observed in esophageal adenocarcinoma. Tobacco use has also been found as a possible risk factor for adenocarcinoma of the esophagus and gastric cardia. Infection with Helicobacter pylori and the use of nonsteroidal anti-inflammatory drugs might reduce the risk. On the other hand, low intake of fruits, vegetables, and cereal fibers seem to increase the risk of esophageal adenocarcinoma. Currently, there is no evidence that strongly supports any specific strategy to screen a subgroup of the population at risk for adenocarcinoma of the esophagus or esophagogastric junction. Future strategies to decrease obesity and tobacco use might help to reduce the burden of esophageal adenocarcinoma at least partially.

Cigarette smoking and adenocarcinomas of the esophagus and esophagogastric junction: a pooled analysis from the international BEACON consortium

BACKGROUND

Previous studies that showed an association between smoking and adenocarcinomas of the esophagus and esophagogastric junction were limited in their ability to assess differences by tumor site, sex, dose-response, and duration of cigarette smoking cessation.

METHODS

We used primary data from 10 population-based case-control studies and two cohort studies from the Barrett's Esophagus and Esophageal Adenocarcinoma Consortium. Analyses were restricted to white non-Hispanic men and women. Patients were classified as having esophageal adenocarcinoma (n = 1540), esophagogastric junctional adenocarcinoma (n = 1450), or a combination of both (all adenocarcinoma; n = 2990). Control subjects (n = 9453) were population based. Associations between pack-years of cigarette smoking and risks of adenocarcinomas were assessed, as well as their potential modification by sex and duration of smoking cessation. Study-specific odds ratios (ORs) estimated using multivariable logistic regression models, adjusted for age, sex, body mass index, education, and gastroesophageal reflux, were pooled using a meta-analytic methodology to generate summary odds ratios. All statistical tests were two-sided.

RESULTS

The summary odds ratios demonstrated strong associations between cigarette smoking and esophageal adenocarcinoma (OR = 1.96, 95% confidence interval [CI] = 1.64 to 2.34), esophagogastric junctional adenocarcinoma (OR = 2.18, 95% CI = 1.84 to 2.58), and all adenocarcinoma (OR = 2.08, 95% CI = 1.83 to 2.37). In addition, there was a strong dose-response association between pack-years of cigarette smoking and each outcome (P < .001). Compared with current smokers, longer smoking cessation was associated with a decreased risk of all adenocarcinoma after adjusting for pack-years (<10 years of smoking cessation: OR = 0.82, 95% CI = 0.60 to 1.13; and > or =10 years of smoking cessation: OR = 0.71, 95% CI = 0.56 to 0.89). Sex-specific summary odds ratios were similar.

CONCLUSIONS

Cigarette smoking is associated with increased risks of adenocarcinomas of the esophagus and esophagogastric junction in white men and women; compared with current smoking, smoking cessation was associated with reduced risks.

Epidemiological aspects of gastric adenocarcinoma: are predictive diagnostics and targeted preventive measures possible?

The incidence of gastric cancer has witnessed major changes over the past decades. Until recently, gastric cancer was a common malignancy in most countries. A striking decline in incidence in most Western populations has occurred since the 1970s, and elucidating the detailed causes for this trend can potentially be of great value for targeted preventive measures. Furthermore, it can add to the understanding of malignant disease and prevention in general. Moreover, the absolute number of cases worldwide is predicted to increase during many years to come. Gastric cancer is typically diagnosed at an advanced stage in symptomatic patients, and there are often no effective curative or palliative or therapeutic options. This fact highlights the need for research aiming to increase our understanding of the etiology of this cancer, facilitating the design of successful targeted preventive strategies for different populations. The future outlook in terms of decreasing gastric cancer deaths would be to identify such intelligent diagnostic tools. In this article, we present a summary of the epidemiology of gastric cancer, with special focus on its etiology.

Sex-specific exposure prevalence of established risk factors for oesophageal adenocarcinoma

BACKGROUND

There is an unexplained male predominance in the incidence of oesophageal adenocarcinoma, and the sex-specific distribution of its risk factors in the general population is not known.

METHODS

A random sample of Swedish citizens aged 40-79 years completed a questionnaire for assessment of the prevalence of five risk factors for oesophageal adenocarcinoma: reflux symptoms, body mass index, tobacco smoking habits, socioeconomic status, and use of non-steroidal anti-inflammatory drugs (NSAIDs). Logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) to evaluate the association of these risk factors, separately and combined, with male sex, with women as reference.

RESULTS

Among 6969 invited people, 4906 (70.4%) completed the questionnaire. Adjusted prevalence estimates showed a negative association with male sex with regard to reflux disease (OR=0.70, 95% CI=0.58-0.84), whereas overweight (OR=1.98, 95% CI=1.72-2.27) and obesity (OR=1.22, 95% CI=1.01-1.47), previous smoking (OR=1.50, 95% CI=1.30-1.72), and no NSAID use (OR=1.35, 95% CI=1.15-1.49) were positively associated.

CONCLUSIONS

Exposure to some but not all established risk factors for oesophageal adenocarcinoma seems to be more common in men than in women, but the differences are small and unlikely to explain the male predominance of this tumour.

Genome-wide association study of esophageal squamous cell carcinoma in Chinese subjects identifies susceptibility loci at PLCE1 and C20orf54

We performed a genome-wide association study of esophageal squamous cell carcinoma (ESCC) by genotyping 1,077 individuals with ESCC and 1,733 control subjects of Chinese Han descent. We selected 18 promising SNPs for replication in an additional 7,673 cases of ESCC and 11,013 control subjects of Chinese Han descent and 303 cases of ESCC and 537 control subjects of Chinese Uygur-Kazakh descent. We identified two previously unknown susceptibility loci for ESCC: PLCE1 at 10q23 (P(Han combined for ESCC) = 7.46 x 10(-56), odds ratio (OR) = 1.43; P(Uygur-Kazakh for ESCC) = 5.70 x 10(-4), OR = 1.53) and C20orf54 at 20p13 (P(Han combined for ESCC) = 1.21 x 10(-11), OR = 0.86; P(Uygur-Kazakh for ESCC) = 7.88 x 10(-3), OR = 0.66). We also confirmed association in 2,766 cases of gastric cardia adenocarcinoma cases and the same 11,013 control subjects (PLCE1, P(Han for GCA) = 1.74 x 10(-39), OR = 1.55 and C20orf54, P(Han for GCA) = 3.02 x 10(-3), OR = 0.91). PLCE1 and C20orf54 have important biological implications for both ESCC and GCA. PLCE1 might regulate cell growth, differentiation, apoptosis and angiogenesis. C20orf54 is responsible for transporting riboflavin, and deficiency of riboflavin has been documented as a risk factor for ESCC and GCA.

Lack of differential pattern in central adiposity and metabolic syndrome in Barrett's esophagus and gastroesophageal reflux disease

Obesity is an established risk factor for esophageal adenocarcinoma, although the mechanism is unclear. A pathway from reflux to inflammation through metaplasia is the dominant hypothesis, and an added role relating to visceral adiposity and the metabolic syndrome has been mooted in Barrett's esophagus (BE) patients. Whether BE differs from gastroesophageal reflux disease (GERD) in obesity and metabolic syndrome profiles is unclear, and this was the focus of this study. Patients with proven BE or GERD were randomly selected from the unit data registry and invited to attend for metabolic syndrome screening, anthropometry studies including segmental body composition analysis, and laboratory tests including fasting lipids, insulin, and C-reactive protein. Metabolic syndrome was defined using the National Cholesterol Education Program (NCEP) and the International Diabetes Federation (IDF) criteria. One hundred and eighteen BE patients and 113 age- and sex-matched GERD controls were studied. The incidence of obesity (body mass index >30 kg/m(2)) was 36% and 38%, respectively, with the pattern of fat deposition predominantly central and an estimated trunk fat mass of 13 and 14 kg, respectively. Using the NCEP criteria, metabolic syndrome was significantly more common in the BE cohort (30% vs 20%, P < 0.05), but there was no significant difference using IDF criteria (42% vs 37%, P= 0.340). Central obesity and the metabolic syndrome are common in both Barrett's and GERD cohorts, but not significantly different, suggesting that central obesity and the metabolic syndrome does not per se impact on the development of BE in a reflux population. In BE, the importance of obesity and the metabolic syndrome in disease progression merits further study.

Expression of P16 and PDGFR-beta in gastric adenocarcinoma

OBJECTIVES

To detect immunohistochemistry expression of p16 and PDGFR-beta on gastric adenocarcinoma.

METHODS

Thirty six patients submitted to surgery for gastric adenocarcinoma between 1998 and 2002 at Santa Casa de Porto Alegre Hospital have been studied. Variables investigated were: age, gender, tumour size and localization, number of dissected and metastatic nodes, histological type, surgical resection extension and pathological staging.

RESULTS

No expression of PDGFR-beta has been detected on surgical specimens. Concerning to p16, loss of expression lower than 10% and 1% has been detected respectively on 89% and 79% of the specimens studied.

CONCLUSION

There has been no correlation among p16 loss and variables studied.

Age-specific trends in incidence of noncardia gastric cancer in US adults

CONTEXT

For the last 50 years, overall age-standardized incidence rates for noncardia gastric cancer have steadily declined in most populations. However, overall rates are summary measures that may obscure important age-specific trends.

OBJECTIVE

To examine effects of age at diagnosis on noncardia gastric cancer incidence trends in the United States.

DESIGN, SETTING, AND PARTICIPANTS

Descriptive study with age-period-cohort analysis of cancer registration data from the National Cancer Institute's Surveillance, Epidemiology, and End Results Program, which covers approximately 26% of the US population. From 1977 through 2006, there were 83,225 adults with incident primary gastric cancer, including 39,003 noncardia cases.

MAIN OUTCOME MEASURES

Overall and age-specific incidence rates, adjusted for period and cohort effects using age-period-cohort models. Results were stratified by race, sex, and socioeconomic status.

RESULTS

Overall age-standardized annual incidence per 100,000 population declined during the study period from 5.9 (95% confidence interval [CI], 5.7-6.1) to 4.0 (95% CI, 3.9-4.1) in whites, from 13.7 (95% CI, 12.5-14.9) to 9.5 (95% CI, 9.1-10.0) in blacks, and from 17.8 (95% CI, 16.1-19.4) to 11.7 (95% CI, 11.2-12.1) in other races. Age-specific trends among whites varied significantly between older and younger age groups (P < .001 for interaction by age): incidence per 100,000 declined significantly from 19.8 (95% CI, 19.0-20.6) to 12.8 (95% CI, 12.5-13.1) for ages 60 to 84 years and from 2.6 (95% CI, 2.4-2.8) to 2.0 (95% CI, 1.9-2.1) for ages 40 to 59 years but increased significantly from 0.27 (95% CI, 0.19-0.35) to 0.45 (95% CI, 0.39-0.50) for ages 25 to 39 years. Conversely, rates for all age groups declined or were stable among blacks and other races. Age-period-cohort analysis confirmed a significant increase in whites among younger cohorts born since 1952 (P < .001).

CONCLUSIONS

From 1977 through 2006, the incidence rate for noncardia gastric cancer declined among all race and age groups except for whites aged 25 to 39 years, for whom it increased. Additional surveillance and analytical studies are warranted to identify risk factors that may explain this unfavorable trend.

Obesity and gastrointestinal cancer

BACKGROUND

There is emerging evidence of a strong association between obesity and gastrointestinal cancer. This review summarizes the evidence from an epidemiological and pathophysiological perspective.

METHODS

Relevant medical literature was identified from searches of PubMed and references cited in appropriate articles were identified. Selection of articles was based on peer review, journal and relevance.

RESULTS

Numerous epidemiological studies consistently identified an increased risk of developing oesophageal adenocarcinoma and colorectal carcinoma in the obese. The association between obesity and other gastrointestinal malignancies was less robust. Sex seems important with respect to cancer risk. Adipose tissue, particularly viscerally located fat, is metabolically active and exerts systemic endocrine effects. Putative pathophysiological mechanisms linking obesity and carcinogenesis include the insulin-like growth factor axis, adipocytokines and sex steroids.

CONCLUSION

A better understanding of the mechanisms that link obesity and cancer may uncover targets for intervention. Tackling obesity may result in a reduction in the incidence in addition to mortality of certain cancers in future.

Comparison of gastric cancer survival following R0 resection in the United States and Korea using an internationally validated nomogram

OBJECTIVE

To compare disease-specific survival (DSS) between the US and Korea following R0 resection for gastric carcinoma (GC).

SUMMARY BACKGROUND DATA

Many studies have described decreased 5-year survival after curative gastrectomy for GC in the West compared with the East. Although clinicopathological presentations of GC are known to vary widely between Eastern and Western countries, including histology, tumor location, and stage at presentation, it remains unclear whether these factors account for differences in survival.

METHODS

All patients undergoing curative intent resections (R0) for GC (1995-2005) were evaluated in 2 independent, single-institution prospectively maintained databases from the US (711 patients) and Korea (1646 patients). Patients receiving neoadjuvant chemotherapy were excluded from this analysis. Patient, surgical and pathologic variables were compared. DSS was determined via multivariate analysis using prognostic variables from an internationally validated GC nomogram that estimates the probability of 5- and 9-year survival.

RESULTS

Age and body mass index were significantly higher in US patients. Location of tumors was more often proximal in the United States (39% vs. 9%, P < 0.0001) and distal in Korea (54% vs. 33%, P < 0.0001). Korean patients had more early stage tumors (42% vs. 28% stage Ia, P < 0.0001) with a higher number of lymph nodes identified (97% vs. 79%, >or=15 lymph nodes, P < 0.0001). The 5-year DSS was higher in Korea than in the United States. After multivariate analysis, applying factors used in the nomogram, DSS of Korean GC patients remained significantly better than that of US patients (HR = 1.3, 95% CI; 1.0-1.6, P = 0.008).

CONCLUSIONS

This study demonstrates better survival for GC patients in Korea compared with the US as determined by multivariate analysis with a validated gastric cancer nomogram. Multiple possibilities can explain this difference.

Barrett's surveillance identifies patients with early esophageal adenocarcinoma

BACKGROUND

Barrett's surveillance for dysplasia is recommended, but few studies have documented the benefit of endoscopic surveillance for dysplasia or cancer.

OBJECTIVES

Using a retrospective study design, we aim to demonstrate the impact of a Barrett's surveillance program on the stage of esophageal adenocarcinoma and identify factors for progression of metaplasia to cancer.

SUBJECTS

The Institutional Review Board at Veterans Affairs Connecticut Healthcare approved the study. We report a retrospective review of a prospectively followed Barrett's cohort in a surveillance program and compared their outcome with patients with a new diagnosis of esophageal adenocarcinoma, identified at the same center between 1999 and 2005.

RESULTS

There were 248 patients with Barrett's esophagus entered into a surveillance program from 1999 to 2005. During the surveillance period of 987 patient-years, 5 (0.5% patient-year) patients developed esophageal adenocarcinoma. During the same period, 46 patients were diagnosed with new-onset esophageal adenocarcinoma outside of our surveillance program. Only 5% of these patients had a history of gastroesophageal reflux disease. There were 248 patients who underwent a mean number of 2.7+/-1.7 upper endoscopic procedures, with 26 (10%) patients developing dysplasia. Compared with nonsurveillance, more patients had early stage of cancer in the surveillance group (P <.001). All 5 patients with cancer diagnosed from Barrett's esophagus surveillance endoscopy were alive, compared with 20 of 46 (43%) patients with cancer diagnosed outside of the surveillance program. The length of Barrett's segment >3 cm was found to be associated with development of dysplasia, P=.004 (odds ratio 1.2; 95% confidence interval, 1.07-1.34).

CONCLUSION

Patients with Barrett's esophagus undergoing endoscopic surveillance benefit from early-stage cancer diagnosis. Progression to adenocarcinoma is low, but long-segment and high-grade dysplasias have an increased risk of cancer. A significant number of patients with newly diagnosed esophageal adenocarcinoma do not complain of gastroesophageal reflux disease and are therefore not investigated for Barrett's esophagus nor entered into surveillance. Patients and physicians can use this information in making a decision about surveillance.

Interactions among genetic variants in apoptosis pathway genes, reflux symptoms, body mass index, and smoking indicate two distinct etiologic patterns of esophageal adenocarcinoma

PURPOSE

Apoptosis pathway, gastroesophageal reflux symptoms (reflux), higher body mass index (BMI), and tobacco smoking have been individually associated with esophageal adenocarcinoma (EA) development. However, how multiple factors jointly affect EA risk remains unclear.

PATIENTS AND METHODS

In total, 305 patients with EA and 339 age- and sex-matched controls were studied. High-order interactions among reflux, BMI, smoking, and functional polymorphisms in five apoptotic genes (FAS, FASL, IL1B, TP53BP, and BAT3) were investigated by entropy-based multifactor dimensionality reduction (MDR), classification and regression tree (CART), and traditional logistic regression (LR) models.

RESULTS

In LR analysis, reflux, BMI, and smoking were significantly associated with EA risk, with reflux as the strongest individual factor. No individual single nucleotide polymorphism was associated with EA susceptibility. However, there was a two-way interaction between IL1B + 3954C>T and reflux (P = .008). In both CART and MDR analyses, reflux was also the strongest individual factor for EA risk. In individuals with reflux symptoms, CART analysis indicated that strongest interaction was among variant genotypes of IL1B + 3954C>T and BAT3S625P, higher BMI, and smoking (odds ratio [OR], 5.76; 95% CI, 2.48 to 13.38), a finding independently found using MDR analysis. In contrast, for participants without reflux symptoms, the strongest interaction was found between higher BMI and smoking (OR, 3.27; 95% CI, 1.88 to 5.68), also echoed by entropy-based MDR analysis.

CONCLUSION

Although a history of reflux is an important risk for EA, multifactor interactions also play important roles in EA risk. Gene-environment interaction patterns differ between patients with and without reflux symptoms.

Sex differences in the incidence of gastrointestinal adenocarcinoma in Sweden 1970-2006

BACKGROUND

Oesophageal and gastric adenocarcinoma share a male predominance not seen for other adenocarcinomas of the gastrointestinal tract. These sex differences are not explained by known risk factors. An endogenous factor, such as premenopausal oestrogen exposure, may act protectively in favour of women and might be detected by scrutinising sex ratios and incidence rates stratified by age.

METHODS

The Swedish Cancer Register was used to collect primary oesophageal, gastric cardia, non-cardia gastric, colonic and pancreatic adenocarcinoma cases aged 25-84, during the study period of 1970-2006. Cases were divided into five-year age groups and crude incidence rates and male: female ratios were calculated. Evaluating potential time period effect, the corresponding results from 1970-1986 and 1987-2006 were also derived.

RESULTS

The sex ratio for oesophageal adenocarcinoma ranged from approximately 10:1 to 4:1, presenting a seemingly consistent decline with age. The sex ratio for non-cardia gastric adenocarcinoma, however, increased with age to reach 2:1 at a point one to two decades after menopause, where the ratio levelled off and eventually declined. There was no discernible time period effect concerning any type of adenocarcinoma. The ratios for gastric cardia, colonic and pancreatic adenocarcinoma were stable with age.

CONCLUSION

This study indicates separate patterns of age-dependency of the sex difference in oesophageal and non-cardia gastric adenocarcinoma incidence. The non-cardia gastric adenocarcinoma pattern might be due to a protective effect during premenopausal years for the female population, while the seemingly steady decline in sex ratio in oesophageal adenocarcinoma indicates a mechanism independent of menopause.

Screening for Barrett's Esophagus

Barrett's esophagus (BE) increases the risk for development of esophageal adenocarcinoma. Because of the rapid rise in incidence of esophageal adenocarcinoma, screening for BE with subsequent surveillance when found has been proposed as a method of early detection. Sedated endoscopy, however, is too expensive for wide spread screening. As a result, other techniques including unsedated transnasal esophagoscopy and capsule esophagoscopy have been proposed to expand screening programs.

Declining death rates reflect progress against cancer

BACKGROUND

The success of the "war on cancer" initiated in 1971 continues to be debated, with trends in cancer mortality variably presented as evidence of progress or failure. We examined temporal trends in death rates from all-cancer and the 19 most common cancers in the United States from 1970-2006.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed trends in age-standardized death rates (per 100,000) for all cancers combined, the four most common cancers, and 15 other sites from 1970-2006 in the United States using joinpoint regression model. The age-standardized death rate for all-cancers combined in men increased from 249.3 in 1970 to 279.8 in 1990, and then decreased to 221.1 in 2006, yielding a net decline of 21% and 11% from the 1990 and 1970 rates, respectively. Similarly, the all-cancer death rate in women increased from 163.0 in 1970 to 175.3 in 1991 and then decreased to 153.7 in 2006, a net decline of 12% and 6% from the 1991 and 1970 rates, respectively. These decreases since 1990/91 translate to preventing of 561,400 cancer deaths in men and 205,700 deaths in women. The decrease in death rates from all-cancers involved all ages and racial/ethnic groups. Death rates decreased for 15 of the 19 cancer sites, including the four major cancers, with lung, colorectum and prostate cancers in men and breast and colorectum cancers in women.

CONCLUSIONS/SIGNIFICANCE

Progress in reducing cancer death rates is evident whether measured against baseline rates in 1970 or in 1990. The downturn in cancer death rates since 1990 result mostly from reductions in tobacco use, increased screening allowing early detection of several cancers, and modest to large improvements in treatment for specific cancers. Continued and increased investment in cancer prevention and control, access to high quality health care, and research could accelerate this progress.

A segregation analysis of Barrett's esophagus and associated adenocarcinomas

Familial aggregation of esophageal adenocarcinomas, esophagogastric junction adenocarcinomas, and their precursor Barrett's esophagus (BE) has been termed familial BE (FBE). Numerous studies documenting increased familial risk for these diseases raise the hypothesis that there may be an inherited susceptibility to the development of BE and its associated cancers. In this study, using segregation analysis for a binary trait as implemented in S.A.G.E. 6.0.1, we analyzed data on 881 singly ascertained pedigrees to determine whether FBE is caused by a common environmental or genetic agent and, if genetic, to identify the mode of inheritance of FBE. The inheritance models were compared by likelihood ratio tests and Akaike's A Information Criterion. Results indicated that random environmental and/or multifactorial components were insufficient to fully explain the familial nature of FBE, but rather, there is segregation of a major type transmitted from one generation to the next (P < 10(-10)). An incompletely dominant inheritance model together with a polygenic component fits the data best. For this dominant model, the estimated penetrance of the dominant allele is 0.1005 [95% confidence interval (95% CI), 0.0587-0.1667] and the sporadic rate is 0.0012 (95% CI, 0.0004-0.0042), corresponding to a relative risk of 82.53 (95% CI, 28.70-237.35) or odds ratio of 91.63 (95% CI, 32.01-262.29). This segregation analysis provides epidemiologic evidence in support of one or more rare autosomally inherited dominant susceptibility allele(s) in FBE families and, hence, motivates linkage analyses.

Barrett's oesophagus and oesophageal adenocarcinoma: time for a new synthesis

The public health importance of Barrett's oesophagus lies in its association with oesophageal adenocarcinoma. The incidence of oesophageal adenocarcinoma has risen at an alarming rate over the past four decades in many regions of the Western world, and there are indications that the incidence of this disease is on the rise in Asian populations in which it has been rare. Much has been learned of host and environmental risk factors that affect the incidence of oesophageal adenocarcinoma, and data indicate that patients with Barrett's oesophagus rarely develop oesophageal adenocarcinoma. Given that 95% of oesophageal adenocarcinomas arise in individuals without a prior diagnosis of Barrett's oesophagus, what strategies can be used to reduce late diagnosis of oesophageal adenocarcinoma?

IGF2R polymorphisms and risk of esophageal and gastric adenocarcinomas

The mannose-6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R) encodes a protein that plays a critical role in tumor suppression, in part by modulating bioavailability of a potent mitogen, insulin-like growth factor-2 (IGF2). We tested the hypothesis that the common nonsynonymous genetic variants in M6P/IGF2R c.901C > G (Leu > Val) in exon 6 and c.5002G > A (Gly > Arg) in exon 34 are associated with risk of esophageal and gastric cancers. Study participants in this population-based study comprise 197 controls and 182 cases, including 105 with esophageal-gastric cardia adenocarcinoma (EGA), 57 with noncardia gastric adenocarcinoma and 20 with esophageal squamous (ES) cell carcinoma. Among white males, odds ratios (ORs) were elevated in relation to carrying at least 1 c.901C > G allele for EGA [OR = 1.9; 95% confidence intervals (CIs) = 1.0-3.6] and noncardia gastric cancer (OR = 2.5; 95% CI = 1.2-5.5), but not ES. Exploratory subgroup analyses suggested that associations between EGA and this variant were stronger among irregular or nonusers of nonsteroidal anti-inflammatory drugs (NSAIDs) (OR = 2.3; 95% CI = 1.2-4.2) and cigarette smokers (OR = 2.1; 95% CI = 1.0-4.2). An association between carrying the c.5002G > A genotype and EGA was not evident. These findings suggest that nonsynonymous polymorphisms in M6P/IGF2R may contribute to the risks of EGA and noncardia adenocarcinomas. Larger studies are required to confirm these findings.

Insulin-like growth factor type I receptor gene expression and obesity in esophageal adenocarcinoma

The objective of this exploratory study was to evaluate the role of the insulin-like growth factor I receptor (IGF-IR) in esophageal adenocarcinoma (EADC). Using quantitative PCR, we studied IGF-IR mRNA expression in 52 well-characterized surgically resected EADC and matched histologically normal esophageal tissues, and examined IGF-IR expression levels in relation to clinicopathologic characteristics, body mass index (BMI), and the common IGF-IR polymorphism (G1013A), recently proposed to modify risk of obesity for EADC. Expression levels of IGF-IR mRNA were not significantly different between EADC and matched histologically normal esophageal epithelia. Although no significant associations were found between IGF-IR expression and BMI, tumor differentiation, stage or survival, when stratified by genotype, patients with the polymorphic A variant had significantly higher IGF-IR expression in EADC tissues compared with matched normal epithelia. These findings suggest that G1013A most likely modulates IGF-IR function, possibly by influencing gene transcription or mRNA stability, and represents a plausible mechanistic link underlying the association between obesity and esophageal malignancy.

The mystery of male dominance in oesophageal cancer and the potential protective role of oestrogen

Oesophageal cancer is the sixth most common form of cancer death globally with almost 400,000 deaths annually. More than 90% of all cases are either adenocarcinomas (OAC) or squamous-cell carcinomas (OSCC). There is a strong male predominance with up to 8 and 3 men for every woman affected with OAC and OSCC, respectively. It has been hypothesised that sex hormonal factors may play a role in the development of oesophageal cancer or more specifically that oestrogen prevents such development. This article reviews the available literature on this topic. Basic science studies suggest an inhibitory effect of oestrogen in the growth of oesophageal cancer cells, and a possible mechanism of any oestrogen protection might be mediated through oestrogen receptors. But from the few epidemiological studies in which the hypothesis of oestrogen protection has been tested, no firm conclusions can yet be drawn of the role of oestrogen in human oesophageal cancer aetiology. More evidence from valid and large human studies is needed before any conclusions can be drawn.

Role of obesity in Barrett's esophagus and cancer

The incidence of esophageal adenocarcinoma (EAC) has increased dramatically in the western world, and there also appears to have been an increase in the incidence of Barrett's esophagus and gastroesophageal reflux disease in recent years. The contemporaneous increase in obesity has focused interest on whether obesity is a risk factor for EAC and its precursors. This article reviews current evidence for the role that overweight/obesity and body fat distribution have in development of the esophagitis metaplasia-dysplasia-adenocarcinoma sequence. Particular attention is paid to the stage at which adiposity may act to influence the risk of EAC, because this determines the importance of weight control and weight loss at each stage in the disease spectrum for the prevention of EAC.

Risk factors for esophageal cancer development

The incidence of esophageal adenocarcinoma is increasing at a rate greater than that of any other cancer in the Western world today. Barrett's esophagus is a clearly recognized risk factor for the development of esophageal adenocarcinoma, but the overwhelming majority of patients with Barrett's esophagus will never develop esophageal cancer. To date, dysplasia remains the only factor useful for identifying patients at increased risk for the development of esophageal adenocarcinoma in clinical practice. Other epidemiologic risk factors include aging, gender, race, obesity, reflux symptoms, smoking, and diet. Factors that may protect against the development of adenocarcinoma include infection with Helicobacter pylori, a diet rich in fruits and vegetables, and consumption of aspirin and NSAIDs.

Physical activity, obesity and risk for esophageal adenocarcinoma

Over the past three decades, an increasing incidence of esophageal adenocarcinoma (EADC) has been reported throughout North America and Europe at a rate exceeding that of any other human solid tumor. Recent studies have clearly implicated chronic gastroesophageal reflux disease and several lifestyle risk factors, including tobacco consumption, diet and obesity, to be associated with increased risk of EADC. Although physical inactivity is now recognized as a risk factor for several chronic diseases including cancer, only a very limited number of studies have specifically evaluated the association between physical activity and esophageal malignancy. Furthermore, the precise biological mechanisms underlying the association between physical activity, obesity and cancer risk remain unclear. Since successful promotion of healthy body weight and exercise may substantially reduce the future incidence of cancer in the population, the purpose of this review is to explore current evidence linking physical activity, obesity and risk of malignancy – specifically EADC.

Assessment of familiality, obesity, and other risk factors for early age of cancer diagnosis in adenocarcinomas of the esophagus and gastroesophageal junction

OBJECTIVES

Adenocarcinomas of the esophagus and adenocarcinomas of the gastroesophageal junction are postulated to be complex genetic diseases. Combined influences of environmental factors and genetic susceptibility likely influence the age at which these cancers develop. The aim of this study was to determine whether familiality and other recognized risk factors are associated with the development of these cancers at an earlier age.

METHODS

A structured validated questionnaire was utilized to collect self-reported data on gastro-esophageal reflux symptoms, risk factors for Barrett's esophagus (BE) and family history, including age of cancer diagnosis in affected relatives from probands with BE, adenocarcinoma of the esophagus, or adenocarcinoma of the gastroesophageal junction, at five tertiary care academic hospitals. Medical records of all relatives reported to be affected were requested from hospitals providing this cancer care to confirm family histories. Familiality of BE/cancer, obesity (defined as body mass index >30), gastroesophageal reflux symptoms, and other risk factors were assessed for association with a young age of cancer diagnosis.

RESULTS

A total of 356, 216 non-familial and 140 familial, cancers were studied. The study population consisted of 292 (82%) men and 64 (18%) women. Mean age of cancer diagnosis was no different in a comparison of familial and non-familial cancers, 62.6 vs. 61.9 years, P=0.70. There were also no significant differences in symptoms of gastroesophageal reflux, body mass index, race, gender, and smoking history between familial and non-familial cancers. Mean age of cancer diagnosis was significantly younger in those who were obese 1 year before diagnosis as compared to those who were non-obese, mean age 58.99 vs. 63.6 years, P=0.008. Multivariable modeling of age at cancer diagnosis showed that obesity 1 year before diagnosis was associated with a younger age of cancer diagnosis (P=0.005) after adjustment for heartburn and regurgitation duration.

CONCLUSIONS

Obesity is associated with the development of esophageal and gastroesophageal junctional adenocarcinomas at an earlier age. Familial cancers arise at the same age as non-familial cancers and have a similar risk factor profile.

Disparities in gastric cancer outcomes among Asian ethnicities in the USA

BACKGROUND

Survival for gastric cancer is reportedly higher in Asians than for other races. It is unclear whether differences in outcome exist among Asian ethnicities. Our objective was to assess gastric cancer survival in Asian ethnic groups in a large heterogeneous population.

METHODS

Asian-Americans treated for gastric adenocarcinoma between 1988 and 2006 were identified from the Los Angeles County Cancer Surveillance Program. Patients were stratified and compared by ethnicity (Korean, Japanese, Chinese, Vietnamese or Filipino).

RESULTS

Of the 1,817 Asian-Americans in the study cohort, 45% (n = 810) were Korean, 25% (n = 462) were Chinese, 11% (n = 193) were Japanese, 10% (n = 188) were Filipino, and 9% (n = 164) were Vietnamese. For the entire cohort Koreans and Filipinos had the longest and shortest median survival (MS), respectively (22.4 and 10.3 months, respectively; P < 0.001). Multivariate analysis demonstrated that Japanese and Filipino ethnicity independently predicted worse survival compared with Korean ethnicity [hazard ratio (HR) 1.37, 95% confidence interval (CI) 1.08-1.73, P = 0.008; and HR 1.71, 95% CI 1.37-2.13, P < 0.001, respectively]. In the surgical cohort, Koreans and Filipinos had the longest and shortest survival, respectively (MS of 57.8 and 21.7 months, respectively; P < 0.001). Multivariate analysis of the surgical cohort also demonstrated that Japanese and Filipino ethnicity independently predicted worse survival compared with Korean ethnicity (HR 1.61, 95% CI 1.22-2.13, P < 0.001; and HR 1.66, 95% CI 1.24-2.22, P < 0.001, respectively).

CONCLUSION

There are differences in gastric cancer survival among Asian ethnicities. Future studies addressing varying environmental exposures and molecular expression patterns in gastric cancer are warranted to better understand these disparities in outcome.

Anthropometry and esophageal cancer risk in the European prospective investigation into cancer and nutrition

BACKGROUND

Increasing evidence suggests that general obesity [measured by body mass index (BMI)] is positively associated with risk of esophageal adenocarcinoma (EAC). In contrast, previous studies have shown inverse relations with esophageal squamous cell carcinoma (ESCC). However, it is still unclear whether body fat distribution, particularly abdominal obesity, is associated with each type of esophageal cancer.

METHODS

We applied multivariable adjusted Cox proportional hazards regression to investigate the association between anthropometric measures and risk of EAC and ESCC among 346,554 men and women participating in the European Prospective Investigation into Cancer and Nutrition. All statistical tests were two sided.

RESULTS

During 8.9 years of follow-up, we documented 88 incident cases of EAC and 110 cases of ESCC. BMI, waist circumference, and waist-to-hip ratio (WHR) were positively associated with EAC risk [highest versus lowest quintile; relative risk (RR), 2.60; 95% confidence interval (95% CI), 1.23-5.51; P(trend) < 0.01; RR, 3.07; 95% CI, 1.35-6.98; P(trend) < 0.003; and RR, 2.12; 95% CI, 0.98-4.57; P(trend) < 0.004]. In contrast, BMI and waist circumference were inversely related to ESCC risk, whereas WHR showed no association with ESCC. In stratified analyses, BMI and waist circumference were significantly inversely related to ESCC only among smokers but not among nonsmokers. However, when controlled for BMI, we found positive associations for waist circumference and WHR with ESCC, and these associations were observed among smokers and nonsmokers.

CONCLUSION

General and abdominal obesity were associated with higher EAC risk. Further, our study suggests that particularly an abdominal body fat distribution might also be a risk factor for ESCC.

[Obesity and cancer]

Obesity which is now well recognized as a public health problem increases the risk of developing cancers. Some systematic review and meta-analyses assessed the strength of associations between body mass index and common cancers such as breast, endometrial, colon and adenocarcinoma of oesophagus. The causal mechanisms remain unexplained. However, epidemiological data and animal models have provided some evidence that hormonal alteration linked to obesity, such as hyperinsulinism, high insulin-like growth factor (IGF-1) levels or biodisponibility, low adiponectin serum level and high oestradiol serum level resulting from an enhanced aromatase activity may have mitogenic and antiapoptotic effects. The inflammation associated with visceral adiposity is another factor which promotes cancer. To date, there are no convincing data that weight loss could improve the prognosis of treated neoplasia. However, a regular physical activity and a limited caloric intake are probably safe in healthy subject to prevent cancer and also in cancer survivors.

A polymorphic variant of the insulin-like growth factor type I receptor gene modifies risk of obesity for esophageal adenocarcinoma

BACKGROUND

To investigate potential biologic mechanisms underlying the association between obesity and risk for esophageal adenocarcinoma (EADC), we studied the frequency of a common polymorphism of the insulin-like growth factor I receptor (IGF-IR) gene in patients with either gastroesophageal reflux disease (GERD), premalignant Barrett esophagus (BE) and or invasive EADC.

METHODS

Using a well characterized series of 431 individuals enrolled in a case-control study, we studied the frequency of the IGF-IR gene polymorphism, G1013A.

RESULTS

On multivariate analysis controlling for age and gender, in comparison to asymptomatic controls, obese individuals with the polymorphic A-variant (G/A, A/A) were found to have significantly increased risk for EADC (OR 4.81; 95%CI 1.09-21.15), whereas obese individuals with the G/G variant were not at statistically significant increased risk (OR 2.69; 95%CI 0.41-17.62). Similarly, compared to asymptomatic controls, only obese individuals with the A-variant (G/A, A/A) were at increased risk for BE (OR 3.11; 95%CI 1.12-8.63), while obese individuals with the G/G variant were not at increased risk for BE (OR 2.91; 95%CI 0.69-12.15).

CONCLUSION

We conclude that the common IGF-IR gene polymorphism G1013A modulates the risk of obesity for EADC, an effect most likely mediated by altered the receptor function by influencing gene transcription or mRNA stability. These findings further implicate the insulin-like growth factor axis in the molecular pathogenesis of EADC, and represent a plausible mechanistic link underlying the association between obesity and malignancy.

Pharmacokinetics and pharmacogenomics in esophageal cancer chemoradiotherapy

Esophageal cancer is one of the most lethal malignancies. Surgical resection of the tumor from the primary site has been the standard treatment, especially for localized squamous cell carcinoma, but considerable clinical efforts during the last decade have resulted in novel courses of treatment. These options include chemoradiotherapy, consisting of a continuous infusion of 5-fluorouracil (5-FU), cisplatin (CDDP), and concurrent radiation. Given the substantial inter- and/or intra-individual variation in clinical outcome, future improvements will likely require the incorporation of a novel anticancer drug, pharmacokinetically guided administration of CDDP or 5-FU, and identification of potential responders by patient genetic profiling prior to treatment. In this review, the latest information on incidence, risk factors, biomarkers, therapeutic strategies, and the pharmacokinetically guided or genotype-guided administration of CDDP and 5-FU is summarized for future individualization of esophageal cancer treatment.

Study of association between atrophic gastritis and body mass index: a cross-sectional study in 10,197 Japanese subjects

OBJECTIVES

The aim of this study was to elucidate the association between body mass index (BMI) and both Helicobacter pylori and atrophic gastritis.

METHODS

The study involved 10,197 subjects participating in a Japanese mass endoscopic gastric cancer screening program. Atrophic gastritis was assessed by pepsinogen I to II ratio.

RESULTS

In logistic regression models, BMI had an inverse association with atrophic gastritis, with the odds ratios (OR) decreasing progressively to 0.67 (95% confidence interval [CI] 0.57-0.79, P<0.0001) in the highest BMI quintiles (BMI >or=25.66) group compared with the lowest BMI quintiles (BMI <20.97) group. In linear regression models, atrophic gastritis predicted BMI (regression coefficient -0.326, 95% CI -0.469, -0.184, P<0.0001), whereas H. pylori antibody was not a predictor (regression coefficient 0.072, 95% CI -0.053, 0.198, P=0.3).

CONCLUSIONS

A small, inverse association between BMI and atrophic gastritis was found in the general population. In contrast, no association was observed between H. pylori seropositivity and BMI.

Cigarette smoking, body mass index, gastro-esophageal reflux disease, and non-steroidal anti-inflammatory drug use and risk of subtypes of esophageal and gastric cancers by P53 overexpression

A number of risk factors for esophageal and gastric cancers have emerged, yet little is known whether risk factors map to molecular tumor markers such as overexpression of the tumor suppressor TP53. Using a US multicenter, population-based case-control study (170 cases of esophageal adenocarcinomas, 147 gastric cardia adenocarcinomas, 220 non-cardia gastric adenocarcinomas, and 112 esophageal squamous cell carcinomas), we examined whether the risk associated with cigarette smoking, body mass index (BMI), gastroesophageal reflux disease (GERD), and non-steroidal anti-inflammatory drug (NSAID) use varied by P53 overexpression. We defined P53 overexpression through immunohistochemistry of paraffin-embedded tumor tissues, using cutpoints based on percent of cells positive. Polytomous logistic regression was used to assess differences between each case group (defined by tumor subtype and P53 expression) and the control group by risk factors. The proportion of cases overexpressing P53 by tumor subtype was 72% for esophageal adenocarcinoma, 69% for gastric cardia adenocarcinoma, 52% for non-cardia gastric adenocarcinoma, and 67% for esophageal squamous cell carcinoma. For most tumor subtypes, we found little difference in risk factors by tumor P53 overexpression. For non-cardia gastric cancer however, an association with cigarette smoking was suggested for tumors that do not overexpress P53, whereas larger BMI was related to adenocarcinomas that overexpress P53 versus no overexpression. Overall, this study did not find a clear relationship between P53 protein overexpression and the known risk factors for subtypes of esophageal and gastric cancers. Further research on these tumors is needed to identify molecular markers associated with variations in the risk factor profiles.

High-risk population for gastric cancer development based on serum pepsinogen status and lifestyle factors

BACKGROUND

Gastric atrophy is a major risk factor for non-cardiac gastric cancer. Serum pepsinogen status could identify people at high-risk for gastric cancer development during our previous cohort study. However, lifestyle-related factors may additionally affect this risk.

MATERIALS AND METHODS

A total of 6983 Japanese were followed up by annual endoscopy in the previous study, and 43 cases of gastric cancer including two cardiac cancers developed. In most subjects, the body length and weight were measured and a questionnaire was applied to gather information regarding life habits. The risk of non-cardiac gastric cancer development during surveillance was re-analyzed based on serum pepsinogen, sex, age, body mass index (BMI), alcohol, and smoking habit.

RESULTS

A total of 6158 subjects with 37 non-cardiac gastric cancer development (male/female = 4259/1899, mean age = 49.0, mean follow-up period = 4.79 years) were entered into analysis. In a multivariate analysis, old age (by 10 years; (odds ratio) OR, 2.8; p < .001), alcohol (weekly; OR, 2.4; p = .03), smoking (current; OR, 5.6; p = .006 and past; OR, 3.9; p = .04), and pepsinogen status ("atrophic"; OR, 6.2; p < .001) were independent risk factors, whereas BMI was not. The annual incidence of gastric cancer was 1.2% in the older subjects aged > or = 60 years with "atrophic" pepsinogen status. Moreover, it was as high as 2.9% when they had both alcohol and current smoking habits.

CONCLUSIONS

Old age, alcohol, and smoking habits additionally promoted the risk for gastric cancer in subjects with gastric atrophy.

ErbB receptors in the biology and pathology of the aerodigestive tract

The most common sites of malignancies in the aerodigestive tract include the lung, head and neck and the esophagus. Esophageal adenocarcinomas (EA), esophageal squamous cell carcinomas (ESCC), and squamous cell carcinomas of the head and neck (SCCHN) are the primary focus of this review. Traditional treatment for aerodigestive tract cancers includes primary chemoradiotherapy (CRT) or surgical resection followed by radiation (or CRT). Recent developments in treatment have focused increasingly on molecular targeting strategies including cetuximab (a monoclonal antibody against epidermal growth factor receptor (EGFR)). Cetuximab was FDA approved in 2006 for treatment of SCCHN, underscoring the importance of understanding the biology of these malignancies. EGFR is a member of the ErbB family of growth factor receptor tyrosine kinases. The major pathways activated by ErbB receptors include Ras/Raf/MAPK; PI3K/AKT; PLCgamma and STATs, all of which lead to the transcription of target genes that may contribute to aerodigestive tumor progression. This review explores the expression of ErbB receptors in EA, ESCC and SCCHN and the signaling pathways of EGFR in SCCHN.

Does type 2 diabetes influence the risk of oesophageal adenocarcinoma?

Since hyperinsulinaemia may promote obesity-linked cancers, we compared type 2 diabetes prevalence among oesophageal adenocarcinoma (OAC) patients and population controls. Diabetes increased the risk of OAC (adjusted odds ratio 1.59, 95% confidence interval (CI) 1.04-2.43), although the risk was attenuated after further adjusting for body mass index (1.32, 95% CI 0.85-2.05).

Physical activity and esophageal and gastric carcinoma in a large prospective study

BACKGROUND

Few studies have investigated the relationship of physical activity to esophageal and gastric carcinoma according to histology and anatomic site.

METHODS

This study prospectively investigated the association between physical activity and esophageal and gastric carcinoma in a cohort of 487,732 U.S. men and women, followed from 1995-1996 to December 31, 2003. All analyses were performed in 2007-2008.

RESULTS

During 8 years of follow-up study, 523 cases of esophageal carcinoma (149 squamous cell and 374 adenocarcinoma) and 642 cases of gastric carcinoma (313 cardia and 329 noncardia) were documented. Physical activity was associated with reduced risk of esophageal and gastric adenocarcinomas but was unrelated to esophageal squamous cell carcinoma. The inverse association with physical activity was strongest for gastric noncardia adenocarcinoma (multivariate relative risk [RR] for highest versus lowest physical activity level=0.62, 95% CI=0.44, 0.87). Relationships were weaker but evident for gastric cardia adenocarcinoma (RR=0.83; 95% CI=0.58, 1.19) and esophageal adenocarcinoma (RR=0.75; 95% CI=0.53, 1.06). No significant relationship with physical activity was observed for esophageal squamous cell carcinoma (RR=1.05; 95% CI=0.64, 1.74). Exclusion of cases diagnosed during the first 2 follow-up years did not change those estimates, indicating that the findings are not due to decreased activity levels among participants with undiagnosed cancer at entry.

CONCLUSIONS

Physical activity may play a role in the prevention of upper gastrointestinal tract adenocarcinomas. No association was seen between physical activity and esophageal squamous cell carcinoma.

Energy balance, physical activity, and cancer risk

This chapter posits that cancer is a complex and multifactorial process as demonstrated by the expression and production of key endocrine and steroid hormones that intermesh with lifestyle factors (physical activity, body size, and diet) in combination to heighten cancer risk. Excess weight has been associated with increased mortality from all cancers combined and for cancers of several specific sites. The prevalence of obesity has reached epidemic levels in many parts of the world; more than 1 billion adults are overweight with a body mass index (BMI) exceeding 25. Overweight and obesity are clinically defined indicators of a disease process characterized by the accumulation of body fat due to an excess of energy intake (nutritional intake) relative to energy expenditure (physical activity). When energy intake exceeds energy expenditure over a prolonged period of time, the result is a positive energy balance (PEB), which leads to the development of obesity. This physical state is ideal for intervention and can be modulated by changes in energy intake, expenditure, or both. Nutritional intake is a modifiable factor in the energy balance-cancer linkage primarily tested by caloric restriction studies in animals and the effect of energy availability. Restriction of calories by 10 to 40% has been shown to decrease cell proliferation, increasing apoptosis through anti-angiogenic processes. The potent anticancer effect of caloric restriction is clear, but caloric restriction alone is not generally considered to be a feasible strategy for cancer prevention in humans. Identification and development of preventive strategies that "mimic" the anticancer effects of low energy intake are desirable. The independent effect of energy intake on cancer risk has been difficult to estimate because body size and physical activity are strong determinants of total energy expenditure. The mechanisms that account for the inhibitory effects of physical activity on the carcinogenic process are reduction in fat stores, activity related changes in sex-hormone levels, altered immune function, effects in insulin and insulin-like growth factors, reduced free radical generation, and direct effect on the tumor. Epidemiologic evidence posits that the cascade of actions linking overweight and obesity to carcinogenesis are triggered by the endocrine and metabolic system. Perturbations to these systems result in the alterations in the levels of bioavailable growth factors, steroid hormones, and inflammatory markers. Elevated serum concentrations of insulin lead to a state of hyperinsulinemia. This physiological state causes a reduction in insulin-like growth factor-binding proteins and promotes the synthesis and biological activity of insulin-like growth factor (IGF)-I, which regulates cellular growth in response to available energy and nutrients from diet and body reserves. In vitro studies have clearly established that both insulin and IGF-I act as growth factors that promote cell proliferation and inhibit apoptosis. Insulin also affects on the synthesis and biological availability of the male and female sex steroids, including androgens, progesterone, and estrogens. Experimental and clinical evidence also indicates a central role of estrogens and progesterone in regulating cellular differentiation, proliferation, and apoptosis induction. Hyperinsulinemia is also associated with alterations in molecular systems such as endogenous hormones and adipokines that regulate inflammatory responses. Obesity-related dysregulation of adipokines has the ability to contribute to tumorigenesis and tumor invasion via metastatic potential. Given the substantial level of weight gain in industrialized countries in the last two decades, there is great interest in understanding all of the mechanisms by which obesity contributes to the carcinogenic process. Continued focus must be directed to understanding the various relationships between specific nutrients and dietary components and cancer cause and prevention. A reductionist approach is not sufficient for the basic biological mechanisms underlying the effect of diet and physical activity on cancer. The joint association between energy balance and cancer risk are hypothesized to share the same underlying mechanisms, the amplification of chemical mediators that modulate cancer risk depending on the responsiveness to those hormones to the target tissue of interest. Disentangling the connection between obesity, the insulin-IGF axis, endogenous hormones, inflammatory markers, and their molecular interaction is vital.

Energy intake, physical activity, energy balance, and cancer: epidemiologic evidence

Energy intake, physical activity, and obesity are modifiable lifestyle factors. This chapter reviews and summarizes the epidemiologic evidence on the relation of energy intake, physical activity, and obesity to cancer. High energy intake may increase the risk of cancers of colon-rectum, prostate (especially advanced prostate cancer), and breast. However, because physical activity, body size, and metabolic efficiency are highly related to total energy intake and expenditure, it is difficult to assess the independent effect of energy intake on cancer risk. There are sufficient evidences to support a role of physical activity in preventing cancers of the colon and breast, whereas the association is stronger in men than in women for colon cancer and in postmenopausal than in premenopausal women for breast cancer. The evidence also suggests that physical activity likely reduces the risk of cancers of endometrium, lung, and prostate (to a lesser extent). On the other hand, there is little or no evidence that the risk of rectal cancer is related to physical activity, whereas the results have been inconsistent regarding the association between physical activity and the risks of cancers of pancreas, ovary and kidney. Epidemiologic studies provide sufficient evidence that obesity is a risk factor for both cancer incidence and mortality. The evidence supports strong links of obesity with the risk of cancers of the colon, rectum, breast (in postmenopausal women), endometrium, kidney (renal cell), and adenocarcinoma of the esophagus. Epidemiologic evidence also indicates that obesity is probably related to cancers of the pancreas, liver, and gallbladder, and aggressive prostate cancer, while it seems that obesity is not associated with lung cancer. The role of obesity in other cancer risks is unclear.

Early gastric cancer shows different associations with adipose tissue volume depending on histological type

BACKGROUND

Visceral obesity is known to be a risk factor for diabetes and cardiovascular disease. Cancer of the gastric cardia has been shown to have a close association with obesity in Western countries. In order to examine the possible relationship between fat volume and the development of gastric cancer (GC), we quantified visceral and subcutaneous fat areas of computed tomography (CT) images of patients with early GC.

METHODS

A total of 210 patients who underwent endoscopic resection or surgical gastrectomy and whose disease was pathologically diagnosed as early GC were investigated for total fat area (TFA), visceral fat area (VFA), and subcutaneous fat area (SFA) with Fat Scan software, using a CT slice at the umbilical level, and the relationships of these findings with clinical and pathological data were analyzed. The same analysis was performed in 147 patients with early colorectal cancer (CRC).

RESULTS

TFA, VFA, and SFA values in GC patients were not significantly different from the values in CRC patients. These values did not differ with the location of the GC. However, patients with undifferentiated-type GC had significantly smaller VFAs and SFAs than those with differentiated-type GC. Among the patients with undifferentiated GC, TFA and SFA values in the patients with submucosal cancer were significantly smaller than those in the patients with mucosal cancer.

CONCLUSION

GC has different associations with adipose tissue volume according to its histological type. As compared with differentiated GC, lower adipose tissue volume may be a preferential environment for the development and progression of undifferentiated GC.

Barrett's esophagus: can biomarkers predict progression to malignancy?

Barrett's esophagus (BE) is one of the most common premalignant lesions and can progress to esophageal adenocarcinoma. It is characterized histologically by a specialized intestinal metaplasia that replaces the squamous epithelium of the distal esophagus, and is associated with chronic gastroesophageal reflux disease and obesity. Similar to the adenoma-carcinoma sequence of colorectal carcinomas, esophageal adenocarcinoma develops through progression from BE to low- and high-grade dysplasia, then to adenocarcinoma with accumulation of genetic and epigenetic abnormalities. The exact malignancy potential of BE is uncertain. Dysplasia is the most predictive marker for risk of esophageal adenocarcinoma, whereas endoscopic and histological diagnoses are still the gold standard for surveillance of patients with BE. However, both are limited, either by sampling errors in biopsies or by differences in histological interpretation. Several studies have identified candidate biomarkers that may have predictive value and may serve as additional factors for the risk assessment of esophageal adenocarcinoma. This review discusses the role of biomarkers in the progression from BE to adenocarcinoma, focusing on clinical and molecular markers.

Estimating the number of U.S. incident cancers attributable to obesity and the impact on temporal trends in incidence rates for obesity-related cancers

BACKGROUND

Reaching the American Cancer Society challenge goal for the nation to reduce cancer incidence by 25% by 2015 will be influenced in part by the epidemic of obesity. The purpose of this study was to estimate the impact of obesity on the number obesity-attributable incident cancers in the U.S. in 2007 and on trends on cancer incidence rates.

METHODS

Using estimated relative risks (RRs) for obesity vs. normal weight/height from published meta-analyses and/or large cohort studies, and the prevalence of obese adults from the latest national surveys, attributable risk percent (ARP) and numbers of obesity-attributed incident cancers in 2007 were estimated. Using the ARPs, the impact of obesity trends on trends in incidence rates for certain obesity-related cancers was estimated for the calendar years (1976-1980 through 2001-2004) for which cancer rates and obesity prevalence rates were available.

RESULTS

An estimated 33,966 new cancers (4% of all estimated cancers) in males and 50,535 (7% of all estimated cancers) in females diagnosed in 2007, or 6% of all cancers, may be potentially attributable to obesity. Without the impact of rising obesity rates, incidence rates might have declined (instead of remaining stable) from 1988-1994 to 2001-2004 for uterus, breast and certain other cancers.

CONCLUSIONS

Obesity may contribute to about 6% of U.S. incident cancers, apparently has affected recent trends in incidence rates for certain cancers, and is important because of increasing prevalence in the U.S. population.

The association between obesity and GERD: a review of the epidemiological evidence

The current epidemics of obesity and gastroesophageal reflux disease (GERD)-related disorders have generated much interest in studying the association between them. Results of multiple studies indicate that obesity satisfies several criteria for a causal association with GERD and some of its complications, including a generally consistent association with GERD symptoms, erosive esophagitis, and esophageal adenocarcinoma. An increase in GERD symptoms has been shown to occur in individuals who gain weight but continue to have a body mass index (BMI) in the normal range, contributing to the epidemiological evidence for a possible dose-response relationship between BMI and increasing GERD. Data are less clear on the relationship between Barrett's esophagus (BE) and obesity. However, when considered separately, abdominal obesity seems to explain a considerable part of the association with GERD, including BE. Overall, epidemiological data show that maintaining a normal BMI may reduce the likelihood of developing GERD and its potential complications.

Trends in esophageal cancer incidence by histology, United States, 1998-2003

Esophageal adenocarcinoma rates may be increasing, whereas, squamous cell carcinoma rates appear to be decreasing in the United States. Previous population-based research on esophageal cancer has only covered up to 68% of the country. Additional, updated research on a larger percentage of the country is needed to describe racial, ethnic and regional trends in histologic subtypes of esophageal cancer. Invasive esophageal cancer cases diagnosed between 1998 and 2003 (n = 65,926), collected by the National Program of Cancer Registries or the Surveillance, Epidemiology, and End Results program, were included. These data cover 83% of the US population. Esophageal squamous cell carcinoma incidence fell by 3.6%/year, whereas esophageal adenocarcinoma increased by 2.1%/year. Squamous cell carcinoma rates decreased among both sexes in most racial or ethnic groups, whereas adenocarcinoma rates increased primarily among white or non-Hispanic men. Except for white or non-Hispanic men, squamous cell carcinoma rates were similar to, or greater than, adenocarcinoma rates for men and women of all other races and ethnicities. The largest decrease in squamous cell carcinoma rates occurred in the West census region, which also exhibited no increase in adenocarcinoma rates. The rate of regional and distant-staged adenocarcinomas increased, while rates for local-staged adenocarcinoma remained stable. This is the first article to characterize esophageal cancer trends using data covering the majority of the US. Substantial racial, ethnic and regional variation in esophageal cancer is present in the US. Our work may inform interventions related to tobacco and alcohol use, and overweight/obesity prevention, and provide avenues for further research.

Multidisciplinary treatment of advanced cancer of the esophagus and gastroesophageal junction: a European center's approach

Tremendous progress has been made in surgery for cancer of the esophagus and gastroesophageal junction. After primary surgery, overall 5-year survival rates of 35% or more are obtained in high-volume units, and for advanced stage III cancer, 5-year survival reaches 25%. Multimodality therapy, in particular induction chemotherapy with or without radiotherapy, results in a complete response rate in up to 25% of the patients. Approximately 50% of the patients receiving such treatment do not respond, however, and their outcome is dismal. Therefore, further efforts are needed to elaborate more precise algorithms for selecting candidates for induction therapy versus primary surgery.

Food group intake and risk of subtypes of esophageal and gastric cancer

Incidence rates for adenocarcinomas of the esophagus and gastric cardia have been increasing rapidly, while rates for non-cardia gastric adenocarcinoma and esophageal squamous cell carcinoma have declined. We examined food group intake as a risk factor for subtypes of esophageal and gastric cancers in a multicenter, population-based case-control study in Connecticut, New Jersey and western Washington state. Associations between food groups and risk were estimated using adjusted odds ratios (OR), based on increasing intake of one serving per day. Total vegetable intake was associated with decreased risk of esophageal adenocarcinoma (OR = 0.85, 95% CI = 0.75, 0.96). Conversely, total meat intake was associated with increased risk of esophageal adenocarcinoma (OR = 1.43, 95% CI = 1.11, 1.83), gastric cardia adenocarcinoma (OR = 1.37, 95% CI = 1.08, 1.73) and noncardia gastric adenocarcinoma (OR = 1.39, 95% CI = 1.12, 1.71), with red meat most strongly associated with esophageal adenocarcinoma risk (OR = 2.49, 95% CI = 1.39, 4.46). Poultry was most strongly associated with gastric cardia adenocarcinoma (OR = 1.89, 95% CI = 1.15, 3.11) and noncardia gastric adenocarcinoma (OR = 1.90, 95% CI = 1.19, 3.03). High-fat dairy was associated with increased risk of both esophageal and gastric cardia adenocarcinoma. Higher intake of meats, particularly red meats, and lower intake of vegetables were associated with an increased risk of esophageal adenocarcinoma, while higher intake of meats, particularly poultry, and high-fat dairy was associated with increased risk of gastric cardia adenocarcinoma.

Obesity surgery and malignancy: our experience after 1500 cases

BACKGROUND

Obesity is a risk factor for cancer and is associated with increased mortality from a number of malignancies. We describe our experience with bariatric surgery patients with a history of malignancy and review the safety and outcomes of bariatric surgery in patients with a history of cancer.

METHODS

We performed a retrospective review of prospectively collected data from all patients diagnosed with a malignancy before, during, or after bariatric surgery. Data on weight loss, co-morbidities, and recurrence were collected.

RESULTS

From July 1999 to February 2008, 1566 patients underwent bariatric surgery. Of these 1566 patients, 36 (2.3%) had a history of malignancy before they underwent bariatric evaluation and surgery, 4 (0.26%) were diagnosed with a malignancy during their preoperative evaluation, 2 of whom subsequently underwent bariatric surgery, and 2 had intraoperative findings suspicious for malignancy; bariatric surgery was completed in both cases. The evaluation revealed renal cell carcinoma and low-grade lymphoma, respectively. No procedures were aborted because of a suspicion of malignancy. Postoperatively, 16 patients (0.9%) were diagnosed with cancer, 3 of whom had a history of malignancy: 1 with metastatic renal cell, 1 with recurrent melanoma, and 1, who had had prostate cancer, with bladder cancer.

CONCLUSION

A history of malignancy does not appear to be a contraindication for bariatric surgery as long as the life expectancy is reasonable. Screening for bariatric surgery might reveal the malignancy. Bariatric surgery does not seem to have a negative effect on the treatment of malignancies that are discovered in the postoperative period.