The influence of age, sex, and race on the incidence of esophageal cancer in the United States (1992-2006)

Obesity is associated with higher prevalence of gastroesophageal reflux disease and reflux related complications: A global healthcare database study

BACKGROUND

Prior studies have demonstrated that obesity may be associated with the development of gastroesophageal reflux disease (GERD) and GERD-related complications. However, such association has never been assessed in a global-wide real-world patient population.

METHODS

The TriNetX electronic health records network, which involves 92 healthcare organizations in 12 countries, was utilized for this multicenter global health research network study. The cohort with obesity comprised adult patients with body mass index (BMI) of more than 30 kg/m2. We performed 1:1 propensity score matching to decrease confounders effects. The prevalence of GERD and GERD-related complications including erosive esophagitis, Barrett's esophagus (BE), BE with dysplasia, and esophageal adenocarcinoma were assessed.

RESULTS

A total of 2,356,548 patients were included in the obesity and non-obesity groups after propensity score matching. In the group with obesity, patients had a significantly higher prevalence of GERD (30% vs. 24%, OR 1.35, 95% CI 1.34-1.36) compared to the group without obesity. Further analysis showed a higher prevalence of GERD-related complications in the group with obesity with statistical significance: Erosive esophagitis (OR 1.07, 95% CI 1.05-1.08), Barrett's esophagus (1.08, 1.05-1.10), BE with dysplasia (1.11, 1.04-1.18), esophageal cancer (1.32, 1.15-1.51).

CONCLUSION

Globally, obesity was associated with a higher prevalence of GERD and GERD-related complications.

Age-Related Sex Disparities in Esophageal Cancer Survival: A Population-Based Study in the United States

Background

The association between sex and the survival of patients with esophageal cancer (EC) remains controversial. We sought to systematically investigate sex-based disparities in EC survival using the Surveillance, Epidemiology, and End Results (SEER) registry data from the United States.

Methods

Patients with EC diagnosed from 2004 to 2015 registered in the SEER database were selected. The association between sex and cancer-specific survival (CSS) was evaluated using survival analysis. The Inverse Probability Weighting (IPW) approach was applied to reduce the observed bias between males and females. Subgroup analyses were used to investigate the robustness of the sex-based disparity and to explore potential interaction effects with other variables.

Results

Overall, 29,312 eligible EC patients were analyzed, of whom 5,781 were females, and 23,531 were males. Females had higher crude CSS compared to males (10-year CSS: 24.5 vs. 21.3%; P < 0.001). Similar results were obtained after adjusting for selection bias using the IPW approach and multivariate regression. Subgroup analyses confirmed the relative robustness of sex as a prognostic factor. However, significant interactions were observed between sex and other variables, such as age, race, tumor grade, histology, and treatment modality. In particular, there was no survival advantage for premenopausal females compared to their male counterparts, but the association between sex and EC survival was prominent in 46-55-year-old patients.

Conclusions

Female EC patients had better long-term survival than males. The association between sex and EC survival vary according to age, race, tumor grade, histology, and treatment modality. Sex-based disparity in EC-specific survival was age-related in the United States population.

Esophageal Adenocarcinoma: Opportunities for Targeted Prevention in Ohio

Objective:

The incidence of esophageal adenocarcinoma, one of the most lethal gastroenterological diseases, has been increasing since the 1960s. Prevention of esophageal adenocarcinoma is important because no early detection screening programs have been shown to reduce mortality. Obesity, gastroesophageal reflux disease, and tobacco smoking are risk factors for esophageal adenocarcinoma. Due to the high prevalence in Ohio of obesity (32.6%) and cigarette smoking (21.0%), this study sought to identify trends and patterns of these risk factors and esophageal adenocarcinoma in Ohio as compared with the United States.

Methods:

Data from the Ohio Cancer Incidence Surveillance System, Surveillance Epidemiology and End Results Program (SEER), and Behavioral Risk Factor Surveillance System were used. Incidence rates overall, by demographics and by county, as well as trends in incidence of esophageal adenocarcinoma and the percent of esophageal adenocarcinoma among esophageal cancers were examined. Trends in obesity and cigarette smoking in Ohio, and the prevalence of each by county, were reported.

Results:

There was an increasing trend in esophageal adenocarcinoma incidence in Ohio. Ohio’s average annual esophageal adenocarcinoma incidence rate was higher than the SEER rate overall and for each sex, race, and age group in 2009 to 2013. There was also an increasing prevalence of obesity in Ohio. Although the prevalence of cigarette smoking has been stable, it was high in Ohio compared with the United States.

Conclusions:

Health care providers and researchers should be aware of the esophageal adenocarcinoma incidence rates and risk factor patterns and tailor interventions for areas and populations at higher risk.

Barrett's Esophagus and Esophageal Adenocarcinoma: How Common Are They Really?

Since the early 1970s, the incidence of esophageal adenocarcinoma (EA) has increased dramatically in most Western populations while the incidence of esophageal squamous cell carcinoma has decreased. As a result, EA has become the predominant subtype of esophageal cancer in North America and Europe and is an important contributor to overall cancer mortality. Barrett's esophagus (BE), a metaplastic columnar epithelium of the distal esophagus, is the known precursor lesion for EA. EA and BE occur more frequently in white men over 50 years old, as well as in people with frequent symptoms of gastroesophageal reflux, in smokers, and in people who are obese. Conversely, EA and BE are less common in persons using nonsteroidal anti-inflammatory drugs and in person with Helicobacter pylori infection. The 5-year survival rate for patients with EA, although generally poor, has improved during the past decade, and long-term survival is increasingly possible for patients with early or locally advanced disease. This review combines a synthesis of published studies with an analysis of data from the United States National Cancer Institute's Surveillance, Epidemiology, and End Results program to discuss the change in incidence of EA and summarize current knowledge of risk factors.

HER-2 Protein Overexpression in Patients with Gastric and Oesophageal Adenocarcinoma at a Tertiary Care Facility in Ghana

The prognosis of gastric and oesophageal adenocarcinoma remains generally poor. However, mounting evidence suggests a positive role of human epidermal growth factor receptor-2 (HER-2) expression in the prognosis of patients with these cancers. In this work, the patterns of HER-2 protein expression were determined in patients with gastric or oesophageal adenocarcinoma. Retrospectively, we reviewed records of gastric and oesophageal biopsies received from 2008 to 2012 and their corresponding archived formalin-fixed paraffin-embedded tissue blocks selected for immunohistochemical analysis. The prevalence of gastric and oesophageal adenocarcinomas and their association with HER-2 protein overexpression were evaluated. Gastric adenocarcinoma made up 18.79% of the gastric biopsies reviewed, and majority of these cancers occurred in males. Regarding the tumour type, HER-2 overexpression was common in the intestinal subtype compared to the diffuse type. Although squamous cell carcinoma was observed to be the commonest (31%) tumour type in the oesophagus compared to adenocarcinoma (8.79%), HER-2 was overexpressed in 42.9% of oesophageal adenocarcinomas, like gastric adenocarcinoma (41.4%). There is a high prevalence of gastric and oesophageal adenocarcinoma, with significant overexpression of HER-2 in these tumours, a window of hope for the management of patients with these cancers.

Trends in esophageal cancer survival in United States adults from 1973 to 2009: A SEER database analysis

BACKGROUND AND AIM

The rise in incidence of esophageal cancer (EC) in the USA over the last four decades has been well documented; however, data on trends in long-term survival and impact on modern therapies associated with survival are lacking.

METHODS

The Surveillance, Epidemiology, and End Results database was queried to identify patients with confirmed EC. Cox proportional hazard regression was used to determine independent mortality factors.

RESULTS

Of 93 167 patients diagnosed with EC between 1973 and 2009, 49% had a histologic diagnosis of esophageal adenocarcinoma (EAC). There was an increase (almost double) in the proportion of patients with adenocarcinoma from the 1970s to 2000s (n = 2,350; 35% to n = 32,212; 61%, P < 0.001). Surgery was performed for localized disease in a majority of EC regardless of type (n = 46 683; 89%). Use of surgical treatment increased significantly over the study period (49% to 64%, P < 0.001). There was also an increase in overall median survival (6 months versus 10 months, P < 0.001) and 5-year survival rate (9% to 22%, P < 0.001). Median survival increased consistently for EAC and squamous cell carcinoma (SCC) until the 1990s. After this period, median survival of EAC continued to increase more rapidly while SCC remained relatively stable.

CONCLUSION

A significant survival improvement in esophageal cancer was seen from 1973 to 2009, largely because of earlier detection at a curative stage and greater utilization of treatment modalities (especially surgery). Despite the rising prevalence, patients with EAC have better long-term survival outcomes than those SCC.

Estrogen Enhances Esophageal Barrier Function by Potentiating Occludin Expression

BACKGROUND

We recently demonstrated that a female sex hormone, estrogen, suppressed esophageal epithelial injury in a reflux esophagitis model of rat, suggesting that estrogen may play an important role in controlling the progress of the gastro-esophageal reflux disease spectrum. However, the precise mechanism of the action is unclear.

AIM

To investigate the potential role of estrogen in the esophageal barrier function.

METHODS

Male rabbits were pretreated with either continuous release 17β-estradiol or placebo, and the excised esophageal mucosa was subjected to Ussing chamber experiments after the 2-week pre-treatment. The mucosal side of the chamber was perfused with luminal irritants (HCl or acidified sodium nitrite), while the basal side was perfused by modified Krebs buffer. The epithelial barrier function was evaluated by the transmembrane resistance and the epithelial permeability. The intercellular space of the epithelium was investigated with transmission electron microscopy and the expression of tight junction protein, occludin, claudin-1, and claudin-4, with immunoblotting.

RESULTS

Estrogen pre-treatment significantly attenuated the decrease in the transmembrane resistance and the increase in the epithelial permeability induced by luminal irritants. Furthermore, the dilation of the intercellular space induced by luminal HCl was significantly alleviated by 17β-estradiol administration. The baseline occludin expression was significantly potentiated by 17β-estradiol administration.

CONCLUSIONS

This is the first study showing an enhancement of the esophageal barrier function by 17β-estradiol administration. The lack of the protective effect of estrogen could be responsible for the male predominance of erosive reflux esophagitis.

The Male Predominance in Esophageal Adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has increased rapidly during the past 4 decades in many Western populations, including North America and Europe. The established etiological factors for EAC include gastroesophageal reflux and obesity, Helicobacter pylori infection, tobacco smoking, and consumption of fruit and vegetables. There is a marked male predominance of EAC with a male-to-female ratio in incidence of up to 9:1. This review evaluates the available literature on the reasons for the male predominance, particularly an update on epidemiologic evidence from human studies during the past decade. The striking sex difference does not seem to be explained by established risk factors, given that the prevalence of the etiological factors and the strengths of associations between these factors and EAC risk are similar between the sexes. Sex hormonal factors may play a role in the development of EAC; estrogenic exposures may prevent such development, whereas androgens might increase the risk of EAC. However, continuing research efforts are still needed to fully understand the reasons for the male predominance of EAC.

The epidemic of oesophageal carcinoma: Where are we now?

Since the early 1970s, the incidence of oesophageal adenocarcinoma has increased dramatically in most Western populations. In contrast, the incidence of oesophageal squamous-cell carcinoma has decreased in these same populations. Epidemiological studies conducted over the past decade have provided great insights into the etiology of oesophageal cancer. These studies have identified gastro-oesophageal reflux disease, obesity and cigarette smoking as risk factors for oesophageal adenocarcinoma, while use of nonsteroidal anti-inflammatory drugs and infection with Helicobacter pylori are associated with reduced risk of oesophageal adenocarcinoma. For oesophageal squamous-cell carcinoma, alcohol and cigarette smoking are the two major risk factors underlying most cases. This review combines a synthesis of these studies with an analysis of data from the United States National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program to discuss the change in incidence of oesophageal cancer and summarize current knowledge of risk factors.

Epidemiology of Barrett's Esophagus and Esophageal Adenocarcinoma

Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC), a disease with increasing burden in the Western world, especially in white men. Risk factors for BE include obesity, tobacco smoking, and gastroesophageal reflux disease (GERD). EAC is the most common form of esophageal cancer in the United States. Risk factors include GERD, tobacco smoking, and obesity, whereas nonsteroidal antiinflammatory drugs and statins may be protective. Factors predicting progression from nondysplastic BE to EAC include dysplastic changes on esophageal histology and length of the involved BE segment. Biomarkers have shown promise, but none are approved for clinical use.

Chemoprevention in Barrett's Esophagus: Current Status

Chemoprevention in Barrett's esophagus is currently applied only in research settings. Identifying pathways that can be targeted by safe, pharmaceutical or natural compounds is key to expanding the scope of chemoprevention. Defining meaningful surrogate markers of cancer progression is critical to test the efficacy of chemopreventive approaches. Combinatorial chemoprevention that targets multiple components of the same pathway or parallel pathways could reduce the risk and improve the efficacy of chemoprevention. Here we discuss the role of chemoprevention as an independent or an adjuvant management option in BE-associated esophageal adenocarcinoma.

Predictors of Progression to High-Grade Dysplasia or Adenocarcinoma in Barrett's Esophagus

The prevalence of esophageal adenocarcinoma is increasing dramatically. Barrett's esophagus remains the most well-established risk factor for the development of esophageal adenocarcinoma. There are multiple clinical, endoscopic, and pathologic factors that increase the risk of neoplastic progression to high-grade dysplasia or esophageal adenocarcinoma in Barrett's esophagus. This article reviews both risk and protective factors for neoplastic progression in patients with Barrett's esophagus.

Chemoprevention in Barrett's oesophagus

Increasing incidence of oesophageal adenocarcinoma along with poor survival entails novel preventive strategies. Agents that target pro-oncogenic pathways in Barrett's mucosa could halt this neoplastic transformation. In this review, we will use epidemiological associations and molecular mechanisms to identify novel chemoprevention targets in Barrett's oesophagus. We will also discuss recent chemoprevention trials.

Age and sex differences in the incidence of esophageal adenocarcinoma: results from the Surveillance, Epidemiology, and End Results (SEER) Registry (1973-2008)

Risk factors driving sex disparity in esophageal cancer are unclear. Recent molecular evidence suggests hormonal factors. We conducted a national descriptive epidemiological study to assess the hypothesis that estrogen exposure could explain the male predominance in observed esophageal adenocarcinoma incidence. We analyzed the esophageal cancer incidence trends by histology and sex from 1973 to 2008 in nine population-based cancer registries of the Surveillance, Epidemiology, and End Results (SEER) 9 Registry Database. We used age as a proxy for estrogen exposure in females. The collective age groups annual percentage change in esophageal adenocarcinoma for females is positive (0.03%; 95% confidence interval: 0.02, 0.03%) during the study period. Interestingly, the esophageal adenocarcinoma annual percentage change in incidence rates for females during the same time period is significantly negative from ages 50-54 to ages 60-64. Even though the incidence of esophageal adenocarcinoma rises in both males and females, the male-to-female ratio across age peaks in the 50-54 years then decreases. Furthermore, the esophageal adenocarcinoma age-adjusted incidence rate in postmenopausal females age 80 and above increases with age unlike their male counterparts. Taken together, these data support the hypothesis that the endocrine milieu in pre- and perimenopausal females serves as a protective factor against esophageal adenocarcinoma, and with loss of estrogen or because of the increasing time period away from estrogen exposure, the rate of esophageal adenocarcinoma incidence increases in the older postmenopausal female. Because females comprise the largest portion of the elderly population with esophageal adenocarcinoma, these findings are significant.

Using stool antigen to screen for Helicobacter pylori in immigrants and refugees from high prevalence countries is relatively cost effective in reducing the burden of gastric cancer and peptic ulceration

OBJECTIVES

Refugees and immigrants from developing countries settling in industrialised countries have a high prevalence of Helicobacter pylori (H. pylori). Screening these groups for H. pylori and use of eradication therapy to reduce the future burden of gastric cancer and peptic ulcer disease is not currently recommended in most countries. We investigated whether a screening and eradication approach would be cost effective in high prevalence populations.

METHODS

Nine different screening and follow-up strategies for asymptomatic immigrants from high H. pylori prevalence areas were compared with the current approach of no screening. Cost effectiveness comparisons assumed population prevalence's of H. pylori of 25%, 50% or 75%. The main outcome measure was the net cost for each cancer prevented for each strategy. Total costs of each strategy and net costs including savings from reductions in ulcers and gastric cancer were also calculated.

RESULTS

Stool antigen testing with repeat testing after treatment was the most cost effective approach relative to others, for each prevalence value. The net cost per cancer prevented with this strategy was US$111,800 (assuming 75% prevalence), $132,300 (50%) and $193,900 (25%). A test and treat strategy using stool antigen remained relatively cost effective, even when the prevalence was 25%.

CONCLUSIONS

H. pylori screening and eradication can be an effective strategy for reducing rates of gastric cancer and peptic ulcers in high prevalence populations and our data suggest that use of stool antigen testing is the most cost effective approach.

Role of Human papilloma virus infection and altered methylation of specific genes in esophageal cancer

BACKGROUND

Evaluation of Human papilloma virus (HPV) and its association with promoter methylation of candidate genes, p53 and Aurora A in esophageal cancer.

MATERIALS AND METHODS

One hundred forty-one esophageal tissue samples from different pathologies were evaluated for HPV infection by PCR, while the promoter methylation status of p53 and Aurora A was assessed by methylation-specific restriction based PCR assay. Statistical analyses were performed with MedCalc and MDR software.

RESULTS

Based on endoscopy and histopathology, samples were categorized: cancers (n=56), precancers (n=7), esophagitis (n=19) and normals (n=59). HPV infection was found to be less common in cancers (19.6%), whereas its prevalence was relatively high in precancers (71.4%), esophagitis (57.8%) and normals (45.7%). p53 promoter methylation did not show any significant difference between cancer and normal tissues, whereas Aurora A promoter methylation demonstrated significant association with disease (p=0.00016, OR:5.6452, 95%CI:2.18 to 14.6) when compared to normals. Aurora A methylation and HPV infection was found in a higher percentages of precancer (66.6%), esophagitis (54.5%) and normal (45.2%) when compared to cancers (14.2%).

CONCLUSIONS

Aurora A promoter methylation is significantly associated with esophageal cancer, but the effect of HPV infection on this epigenetic alteration is not significant. However MDR analysis showed that the hypostatic effect of HPV was nullified when the cases had Aurora methylation and tobacco exposure. Further HPV sub-typing may give an insight into its reduced prevalence in esophageal cancer verses normal tissue. However, with the present data it is difficult to assign any significant role to HPV in the etiopathology of esophageal cancer.

Psychosocial factors and their association with reflux oesophagitis, Barrett’s oesophagus and oesophageal adenocarcinoma

AIM: To investigate the role of psychological characteristics as risk factors for oesophageal adenocarcinoma (OAC), as well as the reflux-mediated precursor pathway.

METHODS: An all-Ireland population-based case-control study recruited 230 reflux oesophagitis (RO), 224 Barrett’s oesophagus (BO) and 227 OAC patients and 260 controls. Each case/control group completed measures of stress, depression, self-efficacy, self-esteem, repression and social support. A comparative analysis was undertaken using polytomous logistic regression adjusted for potential confounders.

RESULTS: Compared to controls, OAC patients were almost half as likely to report high stress levels over their lifetime (P = 0.010, OR 0.51; 95%CI: 0.29-0.90) and 36% less likely to report having experienced depression (OR 0.64; 95%CI: 0.42-0.98). RO patients reported significantly higher stress than controls particularly during middle- and senior-years (P for trends < 0.001). RO patients were 37% less likely to report having been highly emotionally repressed (OR 0.63; 95%CI: 0.41-0.95). All case groups (OAC, RO and BO) were more likely than controls to report having had substantial amounts of social support (OR 2.84; 95%CI: 1.63-4.97; OR 1.97; 95%CI: 1.13-3.44 and OR 1.83; 95%CI: 1.03-3.24, respectively).

CONCLUSION: The improved psychological profile of OAC patients may be explained by response shift. The role of psychological factors in the development of OAC requires further investigation.

Risk of oesophageal adenocarcinoma among individuals born preterm or small for gestational age

BACKGROUND

Gastroesophageal reflux is a main risk factor for oesophageal adenocarcinoma (EAC). Infants born preterm or small for gestational age (SGA) regurgitate more than infants born at term, and some data support the hypothesis of an association with oesophagitis, Barrett's oesophagus and EAC. This study aimed to assess the association between risk of EAC and preterm or SGA birth.

METHODS

In this population-based case-control study, all incident cases of EAC in Sweden between 1st January 1998 and 31st December 2004 with retrievable birth records were eligible as cases. We sampled three matched controls per case from the birth ledger at the same delivery ward as the respective case. Data on gestational age, birth weight and other perinatal exposures were extracted from the original birth records. For comparison, we collected perinatal data for cases of cardia adenocarcinoma and oesophageal squamous cell carcinoma and controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

The risk of EAC increased by 13% per week of shorter duration of gestation (OR 1.1, 95%CI 1.0-1.3), while SGA did not influence the risk. No effect of preterm birth or SGA was found on the risk of cardia adenocarcinoma or oesophageal squamous cell carcinoma.

CONCLUSION

Preterm birth, but not SGA, might lead to an increased risk of EAC as an adult.

Trends in esophageal adenocarcinoma incidence and mortality

BACKGROUND

Over the past several decades, the incidence of esophageal adenocarcinoma (EAC) has rapidly increased. The purpose of this analysis was to examine temporal trends in EAC incidence and mortality within the US population and, in addition, to explore these trends within subgroups of the population.

METHODS

The National Cancer Institute (NCI) Surveillance, Epidemiology and End Results (SEER 9) data were used to examine incidence and incidence-based (IB) mortality in EAC from 1975 to 2009. Secular trends in incidence and IB mortality by cancer stage, sex, and race were further characterized using the NCI's Joinpoint Regression program.

RESULTS

Based on SEER 9 data, EAC incidence and IB mortality continues to increase in the United States. However, since the mid-1990s, the overall rate of increase in both EAC incidence and IB mortality appears to be slowing. In addition, in early-stage cancers, there is a noticeable leveling off of IB mortality rates and divergence from incidence starting in the late 1990s. Over the study period, the average annual percentage increase in incidence was 6.1% in men and 5.9% in women.

CONCLUSIONS

EAC incidence and IB mortality rates continue to rise in the United States, although at a slower rate in more recent years. In early-stage cancers, IB mortality and incidence rates have diverged primarily because IB mortality rates have plateaued beginning in the late 1990s. Although EAC continues to be less common in women, the rate of increase in EAC incidence is similar in both sexes.

Cancer incidence among adolescents and young adults in urban Shanghai, 1973-2005

BACKGROUND

Lack of cancer incidence information for adolescents and young adults led us to describe incidence trends within the young population of 15 to 49 year-olds in urban Shanghai between 1973 and 2005.

METHODS

During 1973 to 2005, data on 43,009 (45.8%) male and 50,828 (54.2%) female cancer cases aged 15-49 years from the Shanghai Cancer Registry were analyzed. Five-year age-specific rates, world age-standardized rates, percent change (PC), and annual percent change (APC) were calculated using annual data on population size and its estimated age structure.

RESULTS

During the 33-year study period, overall cancer incidence of adolescents and young adults among males marginally decreased by 0.5% per year (P<0.05). However, overall cancer incidence for females slightly increased by 0.8% per year (P<0.05). The leading cancer for males in rank were liver, stomach, lung, colorectal, and nasopharyngeal cancers and for females were breast, stomach, colorectal, thyroid, and ovarian cancers. Among specific sites, incidence rates significantly decreased for cancers of the esophagus, stomach, and liver in both sexes. In contrast, incidence rates significantly increased for kidney cancers, non-Hodgkin lymphoma, and brain and nervous system tumors in both sexes and increased for breast and ovarian cancers among females.

CONCLUSIONS

Overall cancer incidence rates of adolescents and young adults decreased in males whereas they increased in females. Our findings suggest the importance of further epidemiology and etiologic studies to further elucidate factors contributing to the cancer incidence trends of adolescents and young adults in China.

Estrogen, male dominance and esophageal adenocarcinoma: is there a link?

Esophageal adenocarcinoma is a cancer with poor prognosis, and its incidence has risen sharply over recent decades. Obesity is a major risk factor for developing this cancer and there is a clear male gender bias in the incidence that cannot be fully explained by known risk factors. It is possible that a difference in the expression of estrogen, or its signaling axes, may contribute to this gender bias. We undertook a comprehensive literature search and analyzed the available data regarding estrogen and estrogen receptor expression, and the possible sex-specific links with esophageal adenocarcinoma development. Potentially relevant associations between visceral vs subcutaneous fat deposition and estrogen expression, and the effect of crosstalk between estrogen and leptin signaling were identified. We also found limited studies suggesting a role for estrogen receptor β expression in esophageal adenocarcinoma development. The current literature supports speculation on an etiological role for estrogen in the male gender bias in esophageal adenocarcinoma, but further studies are required.

Prognostic impact of body mass index stratified by smoking status in patients with esophageal adenocarcinoma

PURPOSE

Given that smoking affects body mass index (BMI) and survival, stratification by smoking status may be required to determine the true prognostic impact of BMI. Although obesity increases risk for developing esophageal adenocarcinoma (EAC), the prognostic influence of obesity and its potential modification by smoking status is unknown in this disease.

PATIENTS AND METHODS

All patients (N = 778) underwent potentially curative esophagectomy. BMI was calculated using measured height and weight at surgery and categorized as obese (≥ 30 kg/m(2)), overweight (25 to 29.9 kg/m(2)), or normal (18.5 to 24.9 kg/m(2)). Cigarette smoking was categorized as never or ever. The association of BMI with disease-specific survival (DSS), disease-free survival (DFS), and overall survival (OS) was determined by Cox regression.

RESULTS

Excess BMI was significantly associated with DSS in a manner that differed substantially by smoking status (P for interaction = .023). Among never smokers, obesity was significantly associated with adverse DSS (hazard ratio [HR] = 2.11; 95% CI, 1.31 to 3.43; P = .002), DFS (HR = 2.03; 95% CI, 1.30 to 3.18; P = .002), and OS (HR = 1.97; 95% CI, 1.24 to 3.14; P = .004), as compared with normal weight, after adjusting for covariates. By contrast, among ever smokers, obesity was not prognostic, and overweight status was significantly associated with favorable survival in univariate, but not multivariate, analysis.

CONCLUSION

Obesity among never smokers was independently associated with two-fold worsening of DSS, DFS, and OS after surgery for EAC, after adjusting for known prognostic factors. These data, in one of the largest reported resected EAC cohorts, are the first to show an adverse prognostic impact of obesity in EAC.

Influence of obesity on the risk of esophageal disorders

Obesity is associated with an increased risk of esophageal disorders, including esophageal adenocarcinoma, Barrett esophagus and GERD. For reasons yet unknown, the association between obesity and esophageal adenocarcinoma seems to be stronger than that for other types of obesity-related cancers. Predominantly abdominal or intra-abdominal adiposity (representing visceral fat and other fat within the abdominal cavity), which is more frequently observed in men than in women, is more strongly linked with these esophageal disorders than BMI alone, a finding that might contribute to the striking male predominance of esophageal adenocarcinoma. Research has identified potential mechanisms underlying the strong link between obesity and esophageal conditions. These findings are summarized in this Review, but more research remains to be carried out before these mechanisms are established.