Epidemiology of esophageal cancer: Orient to Occident. Effects of chronology, geography and ethnicity

A population-based analysis of esophageal and gastric cardia adenocarcinomas in Ontario, Canada: incidence, risk factors, and regional variation

INTRODUCTION

In Western countries, the incidence of esophageal adenocarcinoma (EA) and gastric cardia adenocarcinoma (GCA) is increasing. This population-based study describes the incidence of, associated patient risk factors for, and regional variation in EA/GCA in Ontario, Canada.

METHODS

All adults with a new diagnosis of EA or GCA between 1972 and 2005 in Ontario were identified. Adjusted annual incidence rates were calculated, and multivariate models were used to identify patient risk factors. Maps were created to explore regional variation.

RESULTS

Over the study period, 8,245 persons were diagnosed with EA/CGA; incidence increased from 1.01 to 3.9 per 100,000. Age (>65 vs. <50 years; rate ratio (RR), 3.4; 95% confidence interval (CI), 2.8-4.1) and comorbidity (highest vs. lowest, RR, 3.5; 95% CI, 2.9-4.2) were most strongly associated with the development of EA/GCA. We found considerable regional variation in the rates of EA/GCA (North West vs. Central region, RR, 6.5; 95% CI, 4.4-9.6). Maps suggested ethnicity may explain some regional variation, and that the current allocation of designated surgical treatment centers for EA/CGA may be suboptimal.

CONCLUSIONS

The incidence of EA/GCA is rising dramatically in Ontario. Further investigation of observed regional variation is warranted, particularly for the allocation of cancer health resources.

Detection of erbB2 copy number variations in plasma of patients with esophageal carcinoma

BACKGROUND

Mortality is high in patients with esophageal carcinoma as tumors are rarely detected before the disease has progressed to an advanced stage. Here, we sought to isolate cell-free DNA released into the plasma of patients with esophageal carcinoma, to analyze copy number variations of marker genes in the search for early detection of tumor progression.

METHODS

Plasma of 41 patients with esophageal carcinoma was prospectively collected before tumor resection and chemotherapy. Our dataset resulted heterogeneous for clinical data, resembling the characteristics of the tumor. DNA from the plasma was extracted to analyze copy number variations of the erbB2 gene using real-time PCR assays.

RESULTS

The real-time PCR assays for erbB2 gene showed significant (P = 0.001) copy number variations in the plasma of patients with esophageal carcinoma, as compared to healthy controls with high sensitivity (80%) and specificity (95%). These variations in erbB2 were negatively correlated to the progression free survival of these patients (P = 0.03), and revealed a further risk category stratification of patients with low VEGF expression levels.

CONCLUSION

The copy number variation of erbB2 gene from plasma can be used as prognostic marker for early detection of patients at risk of worse clinical outcome in esophageal cancer.

Current status of Barrett's esophagus research in Asia

In Western countries, the epidemiology of esophageal cancer has changed considerably over the past decades with a rise in the ratio of adenocarcinoma to squamous cell carcinoma. Although the prevalence of gastroesophageal reflux is increasing in Asia, the prevalences of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) have remained low in most Asian countries. The Asian Barrett's Consortium recently conducted a review of published studies on BE from Asia to assess the current status of BE research in Asia, and to recommend potential areas for future BE research in the region. Differences in study design, enrolled population, and endoscopic biopsy protocols used have led to substantial variability in the reported BE prevalence (0.06% to 19.9%) across Asia. In particular, some Japanese studies used diagnostic criteria that differed considerably from what was used in most Asian studies. As in Western countries, increased age, male sex, tobacco smoking, reflux symptoms, and erosive esophagitis have been found to be risk factors for BE in several case-control studies from Asia. The Prague C and M criteria, developed to provide better interobserver reliability in diagnosis and grading of BE, are currently under extensive evaluation in the Asian population. There is a need for standardized protocols for endoscopic and histopathologic diagnosis before initiating collaborative projects to identify etiologic determinants of BE and its ensuing malignant transformation. At present, data regarding the management and long-term outcome of BE are extremely limited in Asia. More studies of BE in this geographic area are warranted.

Global epidemiology of Barrett's esophagus

Barrett's esophagus (BE) is defined as a metaplastic change of the distal esophageal epithelium from squamous to columnar type epithelium with the presence of intestinal metaplasia. There is a striking geographic variation in the prevalence rates of BE. Most epidemiological data on BE are derived from patients undergoing endoscopy and do not reflect prevalence rates in the general population. BE is much more common in the West when compared with Asia and Africa. Although BE is less common in Asia, the demographics are similar to the West, being predominantly found in older men with longer duration of reflux symptoms. Some studies from the West have suggested an increase in prevalence rates of BE. An increase in prevalence rates will have significant implications for health resource utilization and costs, due to the small but significant risk of developing esophageal adenocarcinoma. Endoscopic surveillance with the aim of detecting early lesions has been advocated. Compared with conventional white-light endoscopy with blind four-quadrant biopsies, the use of image-enhanced endoscopy, including chromoendoscopy, may improve detection of subtle mucosal irregularities and facilitate targeted biopsies. However, a truly cost-effective surveillance strategy remains to be determined.

Epidemiology of gastroesophageal reflux disease in Asia: a systematic review

Ethnic and geographical differences are important factors in studying disease frequencies, because they may highlight the environmental or genetic influences in the etiology. We retrieved the studies which have been published regarding the epidemiologic features of gastroesophageal reflux disease (GERD) in Asia, based on the definitions of GERD, study settings, publication years and geographical regions. From the population-based studies, the prevalence of symptom-based GERD in Eastern Asia was found to be 2.5%-4.8% before 2005 and 5.2%-8.5% from 2005 to 2010. In Southeast and Western Asia, it was 6.3%-18.3% after 2005, which was much higher than those in Eastern Asia. There were robust epidemiologic data of endoscopic reflux esophagitis in medical check-up participants. The prevalence of endoscopic reflux esophagitis in Eastern Asia increased from 3.4%-5.0% before 2000, to 4.3%-15.7% after 2005. Although there were only limited studies, the prevalence of extra-esophageal syndromes in Asia was higher in GERD group than in controls. The prevalence of Barrett's esophagus was 0.06%-0.84% in the health check-up participants, whereas it was 0.31%-2.00% in the referral hospital settings. In summary, the prevalence of symptom-based GERD and endoscopic reflux esophagitis has increased in Asian countries. However, the prevalence of Barrett's esophagus in Asia has not changed and also still rare.

Gastroesophageal reflux disease in Asia: A historical perspective and present challenges

Gastroesophageal reflux disease (GERD), previously uncommon in Asia, has now become an important disease in the region. Although much variability exists between studies, most endoscopy-based studies show a prevalence of erosive esophagitis of more than 10%. Symptom-based studies also show a prevalence of 6-10%. Two longitudinal follow-up studies on GERD symptoms have shown an increase with time, and several endoscopy-based time trend studies have also shown a significant increase in erosive reflux esophagitis. Studies on Barrett's esophagus have been confounded by the description of short (SSBE) and long segment (LSBE) Barrett's esophagus. Great variation in prevalence rates has been reported. SSBE vary from 0.1% to more than 20% while LSBE vary from 1-2%. Of the putative causative factors, obesity has been the most important. Many studies have linked GERD-esophagitis as well as occurrence of reflux symptoms with an increase in body mass index (BMI), obesity, especially visceral or central obesity, and metabolic syndrome. A decline in Helicobacter pylori infection with growing affluence in Asia has been broadly thought to result in healthier stomachs and a higher gastric acid output resulting in reflux disease. However, variable results have been obtained from association and H. pylori eradication studies.

Chemopreventive effects of early-stage and late-stage supplementation of vitamin E and selenium on esophageal carcinogenesis in rats maintained on a low vitamin E/selenium diet

Low vitamin E and selenium (Ve/Se) nutritional status is known to be associated with increased risk of esophageal squamous cell carcinoma (ESCC). A previous human intervention trial demonstrated that Ve/Se supplementation decreased the occurrence of esophageal cancer death among younger participants but not among older ones. In this study, we intended to mimic this human nutritional status to determine the chemopreventive effects of Ve/Se supplementation at the early or late stage of esophageal carcinogenesis in rats maintained on a low Ve/Se diet. ESCC was induced in F344 rats with N-nitrosomethylbenzylamine (NMBzA) (0.35 mg/kg body wt, subcutaneously, three times per week for 5 weeks). The rats were maintained on a modified AIN-93M diet with low levels of Ve/Se or supplementation to the normal level by using the AIN-93M diet. At Week 25, the numbers of visible tumors and ESCC were significantly lower in rats on AIN-93M diet during the entire experimental period (Group D) or during the early stage (Group B) but not during the late stage (Group C). Ve/Se supplementation (switching from the low Ve/Se diet to the AIN-93M diet) also decreased cell proliferation, angiogenesis, 8-hydroxy-2'-deoxyguanosine, biosynthesis of prostaglandin E2 and leukotriene B4, expression of cyclooxygenase 2 and 5-lipoxygenase in the esophagus. Our results demonstrated that Ve/Se supplementation inhibited NMBzA-induced esophageal carcinogenesis in rats on low Ve/Se diet, and supplementation during the early stage is more effective than during the late stage of carcinogenesis.

CpG island methylator phenotype of cell-cycle regulators associated with TNM stage and poor prognosis in patients with oesophageal squamous cell carcinoma

Aims

CpG island methylator phenotype (CIMP) involves the targeting of multiple genes by promoter hypermethylation, and the cell-cycle regulatory proteins often change in human neoplasms. To gain insight into the role of epigenetic aberration of cell-cycle regulator genes in oesophagus squamous cell carcinoma (ESCC), the authors determined the hypermethylation profile in ESCC.

Methods

The promoter methylation status of nine cell-cycle regulator genes was examined in 50 ESCC, 50 dysplastic tissues and 50 normal epithelial tissues by methylation-specific PCR.

Results

The frequency of promoter methylation was 52% for p14, 44% for p15, 50% for p16, 56% for p21, 38% for p27, 8% for p53, 42% for p57, 36% for p73, and 44% for RB1 of 50 ESCC. CIMP+ was detected in 54% (27/50) of ESCC and 8% (4/50) of dysplastic tissues; no CIMP+ was present in normal epithelial tissues (p<0.001). The results show that promoter methylation of p14, p15, p16, p21, p27, p57 and p73 was far more common in ESCC samples with CIMP+ than those with CIMP−. A significant difference between CIMP status and TNM stage and metastasis was found in ESCC (p<0.05). Patients with ESCC with CIMP+ had poorer 4-year survival than those with CIMP−.

Conclusions

The results suggest that CIMP of a subset of cell-cycle regulatory genes has an important role in the pathogenesis and progression of ESCC.

Her-2/neu testing and therapy in gastroesophageal adenocarcinoma

Despite ongoing advances in the treatment of gastroesophageal cancer, prognosis remains poor. The best promise to improve this poor survival is provided by new targeted agents. Of these, human epidermal growth factor receptor 2 (HER2) is currently in the spotlight. In this review, we provide an overview of recent developments in HER2 testing and results of clinical trials targeting HER2 in gastroesophageal adenocarcinoma. Based on the encouraging ToGA trial findings it is now expected that routine HER2 testing will be included in the diagnostic work-up of patients with advanced gastric cancer. With regard to this testing, overexpression of the HER2 protein seems to possess the best predictive properties. However, HER2 immunohistochemistry (IHC) is subject to assay and interobserver variability, so standardization and internal and external proficiency testing is an absolute prerequisite, especially as the IHC scoring system in gastric cancer is different from that of breast cancer. Further study is needed to investigate the clinical meaning of the significant heterogeneity observed in both gene amplification and protein overexpression in gastroesophageal cancer. Highly effective therapies for gastroesophageal cancer can only be accomplished by a multi-targeted approach, considering crosstalk between pathways and continuing to optimize chemotherapy.

Vimentin expression of esophageal squamous cell carcinoma and its aggressive potential for lymph node metastasis

Esophageal squamous cell carcinoma (ESCC) has been generally considered as one of the most aggressive cancers with poor prognosis. Vimentin is the major protein constituent of intermediate filaments in normal and neoplastic mesenchymal cells, and has been regarded as a marker of epithelial-mesenchymal transition (EMT). However, little is known about ESCC with vimentin expression as a marker of EMT. In this study, we analyzed vimentin expression in 129 cases of ESCC in order to elucidate whether vimentin expression is correlated with clinicopathological features and aggressive behavior of ESCC. Vimentin expression was identified in 96 of the 129 cases (74.4%). The cases with vimentin-positive carcinoma cells showed a significantly higher incidence of lymph node metastasis (P = 0.001). Carcinomas with vimentin expression were more advanced in terms of tumor status and lymphatic invasion (P = 0.001, P = 0.009, respectively), and associated with stronger stromal alpha-smooth muscle actin (alpha-SMA) expression (P < 0.001). Vimentin expression was also associated with distant metastasis, including distant node metastasis (P = 0.014). Vimentin expression in both primary and metastatic carcinomas was found in 68.6% (48/70) of the cases, while no vimentin expression in both primary and metastatic carcinomas comprised 92.3% of the cases (12/13) (P < 0.001). In conclusion, we demonstrated that vimentin expression in ESCC is an independent predictor of lymph node metastasis (multivariate analysis, P = 0.014, odds ratio: 3.314, 95% confidence interval: 1.276-8.605). In addition, vimentin expression was frequently retained in metastatic carcinoma of the lymph node.

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.

Global patterns of cancer incidence and mortality rates and trends

While incidence and mortality rates for most cancers (including lung, colorectum, female breast, and prostate) are decreasing in the United States and many other western countries, they are increasing in several less developed and economically transitioning countries because of adoption of unhealthy western lifestyles such as smoking and physical inactivity and consumption of calorie-dense food. Indeed, the rates for lung and colon cancers in a few of these countries have already surpassed those in the United States and other western countries. Most developing countries also continue to be disproportionately affected by cancers related to infectious agents, such as cervix, liver, and stomach cancers. The proportion of new cancer cases diagnosed in less developed countries is projected to increase from about 56% of the world total in 2008 to more than 60% in 2030 because of the increasing trends in cancer rates and expected increases in life expectancy and growth of the population. In this review, we describe these changing global incidence and mortality patterns for select common cancers and the opportunities for cancer prevention in developing countries.

Esophageal cancer: an update

Esophageal cancer continues to be a lethal disease with the majority of patients presenting at an advanced stage. The incidence of adenocarcinoma is rising. Although Barrett's esophagus has been well characterized, specific pathways to the development of adenocarcinoma remain undefined. Current treatments for locoregional esophageal cancer include surgery, chemotherapy, radiation therapy, or a combination of these modalities. Optimal surgical treatment strategies include appropriate patient selection, accurate staging and risk assessment, selection of an appropriate surgical approach, and the use of multimodality treatment. This article provides an update on the myriad of options for managing esophageal cancer and outlines the surgical technique for minimally invasive esophagectomy used at our center.

Presentation and survival of operable esophageal cancer in patients 55 years of age and below

BACKGROUND

The increased incidence of esophageal cancer, especially in the younger age group, should encourage early diagnosis. The perceived rarity and poor prognostic outcome of esophageal cancer in this group is based on retrospective studies. The goal of this study was to review the presentation and survival of young patients with esophageal cancer.

METHODS

This study was conducted from 2000 to 2007 in a specialized esophagogastric center. All patients who had esophageal cancer operations were included. Variables collected included ages, duration of symptoms, presenting symptoms, tumor characteristics, and follow-up data.

RESULTS

In total, 365 esophagectomies were performed for cancer, of which 76 patients were younger than aged 55 years (20.8%) and 289 were older than aged 55 years. In patients younger than aged 55 years, 15 patients had symptoms for 6 months or more, 54 had dysphagia, 35 had weight loss compared with 220 and 175 respectively of patients older than aged 55 years. On histopathology, 48 had T3 tumors (63.2%), 17 had T2 (22.4%), and 10 had T1 (13.2%) for patients younger than aged 55 years compared with 141 had T3 (48.7%), 85 had T2 (29.4%), and 55 had T1 (19%) for patients older than aged 55 years. These differences in tumor stage at presentation between groups were significant (p < 0.05 with 3DF). In-hospital mortality was 0 for the group younger than aged 55 years and 5 for those older than aged 55 years. Average follow-up was 35 (minimum, 15) months. Thirty patients had locoregional recurrence in the first group and 110 in the latter group. Survival at 1 year after surgery was 79.6%, at 2 years 65.1%, and at 5 years 42.3% compared with 78.4, 60.6, and 45.9%, respectively, for the group older than aged 55 years, but this was not significant using log-rank (p = 0.99).

CONCLUSIONS

A significant proportion (20.8%) of patients presenting with operable esophageal cancer was younger than aged 55 years. Almost two-thirds of those presenting younger than aged 55 years had T3 stage tumors, which was significantly different than those older than aged 55 years. Despite more advanced tumor stage at presentation, the prognosis of esophageal cancer for patients younger than aged 55 years is similar to those older than aged 55 years (log-rank = 0.99).

Genetic predisposition to gastro-oesophageal cancer

Gastro-oesophageal cancers were ranked as the second cause of death from cancer worldwide despite a steady decrease in incidence for squamous cell carcinoma (SCC) of the oesophagus and distal gastric cancers. Adenocarcinoma of the oesophagus (OAC) is the tumour whose incidence has seen the highest increase in the past 30 years. Most of these cancers are strongly associated with environmental and life style risk factors such as smoking and alcohol for SCC, gastro-oesophageal reflux for OAC and Helicobacter pylori for distal gastric cancer. It may therefore be unsurprising that SCC is associated with polymorphisms in ALDH2 and ADH1B1, enzyme involved in alcohol metabolism, and with CYP1A1, involved in xenobiotics detoxification. OAC, whose incidence in absolute terms remains low, has been much less studied and at best the associations identified with risk are weak. Diffuse type gastric cancers while relatively uncommon have a strong genetic association with mutation of the CDH1 gene and prostate specific cancer antigen (PSCA) was demonstrated in a GWAS to be associated with an increased risk of diffuse gastric cancer but not intestinal type gastric cancer. This family of cancer is more associated with polymorphisms at the IL-1beta, IL-1RN loci and MHTFR loci. Specific strains of H pylori containing the virulence factors VacA s1, VacA m1 and cag A together with polymorphism at the IL-1beta and IL-1RN loci have up to a 87-fold increase in risk for developing intestinal type gastric cancer. While progress has been made to identify genetic variants associated with upper-gastrointestinal cancers, the relative small prevalence for some subtypes underlies the need for consortia, especially in view of the large variations in the prevalence of polymorphisms between different populations.

Probing the link between oestrogen receptors and oesophageal cancer

BACKGROUND

Human oesophageal carcinoma is considered to be one of the most aggressive malignancies and has a very poor prognosis. The incidence of oesophageal cancer shows a gender bias and is higher in males compared with females, the ratio between males and females varying from 3:1 to 7:1. This sex ratio is not entirely attributable to differences in the prevalence of known risk factors between the sexes. The potential role of oestrogen receptors (ER) in oesophageal cancer has been debated for several years but the significance of the receptors in this cancer remains unknown. Most of the work has been based on immunohistochemistry and has not been validated with other available techniques. The inconsistencies in the published literature on the link between ER expression and oesophageal cancer warrant a thorough evaluation of the potential role of ERs in this malignancy. Even the expression of the two ER isoforms, ERalpha and ERbeta, and its implications for outcome of treatments in histological subtypes of oesophageal tumours is ill defined. The aim of this article is to provide updated information from the available literature on the current status of ER expression in oesophageal cancer and to discuss its potential therapeutic role.

METHODS AND RESULTS

We performed a comprehensive literature search and analysed the results regarding ER expression in oesophageal tumours with special emphasis on expression of different oestrogen receptors and the role of sex hormones in oesophageal cancer. This article also focuses on the significance of the two main ER subtypes and mechanisms underlying the presumed male predominance of this disease.

CONCLUSION

We postulate that differential oestrogen receptor status may be considered a biomarker of poor clinical outcome based on tissue dedifferentiation or advanced stage of the disease. Further, if we can establish the importance of oestrogen and its receptors in the context of oesophageal cancer, then this may lead to a new future direction in the management of this malignancy.