Diet and lifestyle factors and risk of subtypes of esophageal and gastric cancers: classification tree analysis

PURPOSE

Although risk factors for squamous cell carcinoma of the esophagus and adenocarcinomas of the esophagus (EA), gastric cardia (GC), and other (noncardia) gastric (OG) sites have been identified, little is known about interactions among risk factors. We sought to examine interactions of diet, other lifestyle, and medical factors with risks of subtypes of esophageal and gastric cancers.

METHODS

We used classification tree analysis to analyze data from a population-based case-control study (1095 cases, 687 controls) conducted in Connecticut, New Jersey, and western Washington State.

RESULTS

Frequency of reported gastroesophageal reflux disease symptoms was the most important risk stratification factor for EA, GC, and OG, with dietary factors (EA, OG), smoking (EA, GC), wine intake (GC, OG), age (OG), and income (OG) appearing to modify the risk of these cancer sites. For esophageal squamous cell carcinoma, smoking was the most important risk stratification factor, with gastroesophageal reflux disease, income, race, noncitrus fruit, and energy intakes further modifying risk.

CONCLUSION

Various combinations of risk factors appear to interact to affect risk of each cancer subtype. Replication of these data mining analyses are required before suggesting causal pathways; however, the classification tree results are useful in partitioning risk and mapping multilevel interactions among risk variables.

Association of marijuana smoking with oropharyngeal and oral tongue cancers: pooled analysis from the INHANCE consortium

BACKGROUND

The incidence of oropharyngeal and oral tongue cancers has increased over the last 20 years which parallels increased use of marijuana among individuals born after 1950.

METHODS

A pooled analysis was conducted comprising individual-level data from nine case-control studies from the United States and Latin America in the INHANCE consortium. Self-reported information on marijuana smoking, demographic, and behavioral factors was obtained from 1,921 oropharyngeal cases, 356 oral tongue cases, and 7,639 controls.

RESULTS

Compared with never marijuana smokers, ever marijuana smokers had an elevated risk of oropharyngeal [adjusted OR (aOR), 1.24; 95% confidence interval (CI): 1.06-1.47] and a reduced risk of oral tongue cancer (aOR, 0.47; 95% CI, 0.29, 0.75). The risk of oropharyngeal cancer remained elevated among never tobacco and alcohol users. The risk of oral tongue cancer was reduced among never users of tobacco and alcohol. Sensitivity analysis adjusting for potential confounding by HPV exposure attenuated the association of marijuana use with oropharyngeal cancer (aOR, 0.99; 95% CI, 0.71-1.25), but had no effect on the oral tongue cancer association.

CONCLUSIONS

These results suggest that the association of marijuana use with head and neck carcinoma may differ by tumor site.

IMPACT

The associations of marijuana use with oropharyngeal and oral tongue cancer are consistent with both possible pro- and anticarcinogenic effects of cannabinoids. Additional work is needed to rule out various sources of bias, including residual confounding by HPV infection and misclassification of marijuana exposure.

A genome-wide association study identifies new susceptibility loci for esophageal adenocarcinoma and Barrett's esophagus

Esophageal adenocarcinoma is a cancer with rising incidence and poor survival. Most such cancers arise in a specialized intestinal metaplastic epithelium, which is diagnostic of Barrett's esophagus. In a genome-wide association study, we compared esophageal adenocarcinoma cases (n = 2,390) and individuals with precancerous Barrett's esophagus (n = 3,175) with 10,120 controls in 2 phases. For the combined case group, we identified three new associations. The first is at 19p13 (rs10419226: P = 3.6 × 10(-10)) in CRTC1 (encoding CREB-regulated transcription coactivator), whose aberrant activation has been associated with oncogenic activity. A second is at 9q22 (rs11789015: P = 1.0 × 10(-9)) in BARX1, which encodes a transcription factor important in esophageal specification. A third is at 3p14 (rs2687201: P = 5.5 × 10(-9)) near the transcription factor FOXP1, which regulates esophageal development. We also refine a previously reported association with Barrett's esophagus near the putative tumor suppressor gene FOXF1 at 16q24 and extend our findings to now include esophageal adenocarcinoma.

Sex-specific associations between body mass index, waist circumference and the risk of Barrett's oesophagus: a pooled analysis from the international BEACON consortium

OBJECTIVE

Barrett's oesophagus is a precursor lesion of oesophageal adenocarcinoma, a cancer that, in the USA, has increased in incidence over 600% during the past 40 years. Barrett's oesophagus and oesophageal adenocarcinoma are much more common among men than among women; this finding is unexplained and most earlier studies lacked sufficient numbers of women to evaluate sex-specific risk factors. We leveraged the power of an international consortium to assess sex-specific relationships between body mass index (BMI), abdominal circumference and Barrett's oesophagus.

DESIGN

Four case-control studies provided a total of 1102 cases (316 women, 786 men) and 1400 population controls (436 women, 964 men) for analysis. Study-specific estimates, generated using individual participant data, were combined using random effects meta-analysis.

RESULTS

Waist circumference was significantly associated with Barrett's oesophagus, even after adjustment for BMI; persons in the highest versus the lowest quartiles of waist circumference had approximately 125% and 275% increases in the odds of Barrett's oesophagus among men and women, respectively (OR 2.24, 95% CI 1.08 to 4.65, I(2)=57; OR 3.75, 95% CI 1.47 to 9.56, I(2)=0). In contrast, there was no evidence of a significant association between BMI and the risk of Barrett's oesophagus, with or without adjustment for waist circumference.

CONCLUSIONS

Waist circumference, independent of BMI, was found to be a risk factor for Barrett's oesophagus among both men and women. Future studies examining the biological mechanisms of this association will extend our knowledge regarding the pathogenesis of Barrett's oesophagus.

Adult height and head and neck cancer: a pooled analysis within the INHANCE Consortium

Several epidemiological studies have shown a positive association between adult height and cancer incidence. The only study conducted among women on mouth and pharynx cancer risk, however, reported an inverse association. This study aims to investigate the association between height and the risk of head and neck cancer (HNC) within a large international consortium of HNC. We analyzed pooled individual-level data from 24 case-control studies participating in the International Head and Neck Cancer Epidemiology Consortium. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated separately for men and women for associations between height and HNC risk. Educational level, tobacco smoking, and alcohol consumption were included in all regression models. Stratified analyses by HNC subsites were performed. This project included 17,666 cases and 28,198 controls. We found an inverse association between height and HNC (adjusted OR per 10 cm height = 0.91, 95% CI 0.86-0.95 for men; adjusted OR = 0.86, 95% CI 0.79-0.93 for women). In men, the estimated OR did vary by educational level, smoking status, geographic area, and control source. No differences by subsites were detected. Adult height is inversely associated with HNC risk. As height can be considered a marker of childhood illness and low energy intake, the inverse association is consistent with prior studies showing that HNC occur more frequently among deprived individuals. Further studies designed to elucidate the mechanism of such association would be warranted.

Temporal and spatial evolution of somatic chromosomal alterations: a case-cohort study of Barrett's esophagus

All cancers are believed to arise by dynamic, stochastic somatic genomic evolution with genome instability, generation of diversity, and selection of genomic alterations that underlie multistage progression to cancer. Advanced esophageal adenocarcinomas have high levels of somatic copy number alterations. Barrett's esophagus is a risk factor for developing esophageal adenocarcinoma, and somatic chromosomal alterations (SCA) are known to occur in Barrett's esophagus. The vast majority (∼95%) of individuals with Barrett's esophagus do not progress to esophageal adenocarcinoma during their lifetimes, but a small subset develop esophageal adenocarcinoma, many of which arise rapidly even in carefully monitored patients without visible endoscopic abnormalities at the index endoscopy. Using a well-designed, longitudinal case-cohort study, we characterized SCA as assessed by single-nucleotide polymorphism arrays over space and time in 79 "progressors" with Barrett's esophagus as they approach the diagnosis of cancer and 169 "nonprogressors" with Barrett's esophagus who did not progress to esophageal adenocarcinoma over more than 20,425 person-months of follow-up. The genomes of nonprogressors typically had small localized deletions involving fragile sites and 9p loss/copy neutral LOH that generate little genetic diversity and remained relatively stable over prolonged follow-up. As progressors approach the diagnosis of cancer, their genomes developed chromosome instability with initial gains and losses, genomic diversity, and selection of SCAs followed by catastrophic genome doublings. Our results support a model of differential disease dynamics in which nonprogressor genomes largely remain stable over prolonged periods, whereas progressor genomes evolve significantly increased SCA and diversity within four years of esophageal adenocarcinoma diagnosis, suggesting a window of opportunity for early detection.

Germline genetic contributions to risk for esophageal adenocarcinoma, Barrett's esophagus, and gastroesophageal reflux

BACKGROUND

Esophageal adenocarcinoma (EA) is an increasingly common cancer with poor survival. Barrett's esophagus (BE) is the main precursor to EA, and every year 0.12% to 0.5% of BE patients progress to EA. BE typically arises on a background of chronic gastroesophageal reflux (GERD), one of the risk factors for EA.

METHODS

We used genome-wide association data to investigate the genetic architecture underlying GERD, BE, and EA. We applied a method to estimate the variance explained (array heritability, h(2)g) and the genetic correlation (rg) between GERD, BE, and EA by considering all single nucleotide polymorphisms (SNPs) simultaneously. We also estimated the polygenic overlap between GERD, BE, and EA using a prediction approach. All tests were two-sided, except in the case of variance-explained estimation where one-sided tests were used.

RESULTS

We estimated a statistically significant genetic variance explained for BE (h(2)g = 35%; standard error [SE] = 6%; one-sided P = 1 × 10(-9)) and for EA (h(2)g = 25 %; SE = 5%; one-sided P = 2 × 10(-7)). The genetic correlation between BE and EA was found to be high (rg = 1.0; SE = 0.37). We also estimated a statistically significant polygenic overlap between BE and EA (one-sided P = 1 × 10(-6)), which suggests, together with the high genetic correlation, that shared genes underlie the development of BE and EA. Conversely, no statistically significant results were obtained for GERD.

CONCLUSIONS

We have demonstrated that risk to BE and EA is influenced by many germline genetic variants of small effect and that shared polygenic effects contribute to risk of these two diseases.

Long-chain omega-3 polyunsaturated fatty acid intake and risk of colorectal cancer

Research suggests that long-chain omega-3 polyunsaturated fatty acids (LC-PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have antineoplastic properties, yet evidence for association between LC-PUFAs and colorectal cancer (CRC) remains inconsistent. Using the VITamins And Lifestyle (VITAL) cohort, we evaluated how EPA/DHA intake, and its primary sources, fish oil supplement use and dark fish consumption, relate to CRC risk. A total of 68,109 Washington residents aged 50-76 completed a questionnaire between 2000-2002 and were followed for CRC through 2008 (n = 488). Persons using fish oil supplements on 4+ days/wk for 3+ yr experienced 49% lower CRC risk than nonusers (hazard ratio = 0.51, 95% CI = 0.26-1.00; P trend = 0.06). The association between fish oil use and decreased CRC risk was primarily observed for men (P interaction = 0.02; P trend men = 0.02; P trend women = 0.88) and for colon cancer (P difference = 0.05; P trend colon = 0.03; P trend rectum = 0.87). Although dark fish and total EPA + DHA intake were not associated with CRC risk overall, these associations varied by genetic risk (P interaction = 0.009 and 0.02, respectively), with inverse associations observed among low-moderate genetic risk groups and positive associations observed among high risk groups. Results suggest that associations between LC-PUFA intake and CRC may vary by gender, subsite, and genetic risk, providing additional insight into the potential role of LC-PUFAs in cancer prevention.

Specialty supplement use and biologic measures of oxidative stress and DNA damage

BACKGROUND

Oxidative stress and resulting cellular damage have been suggested to play a role in the etiology of several chronic diseases, including cancer and cardiovascular disease. Identifying factors associated with reduced oxidative stress and resulting damage may guide future disease-prevention strategies.

METHODS

In the VITamins And Lifestyle (VITAL) biomarker study of 209 persons living in the Seattle area, we examined the association between current use of several specialty supplements and oxidative stress, DNA damage, and DNA repair capacity. Use of glucosamine, chondroitin, fish oil, methylsulfonylmethane (MSM), coenzyme Q10 (CoQ10), ginseng, ginkgo, and saw palmetto was ascertained by a supplement inventory/interview, whereas the use of fiber supplements was ascertained by questionnaire. Supplements used by more than 30 persons (glucosamine and chondroitin) were evaluated as the trend across number of pills/week (non-use, <14 pills/week, 14+ pills/week), whereas less commonly used supplements were evaluated as use/non-use. Oxidative stress was measured by urinary 8-isoprostane and PGF2α concentrations using enzyme immunoassays (EIA), whereas lymphocyte DNA damage and DNA repair capacity were measured using the Comet assay. Multivariate-adjusted linear regression was used to model the associations between supplement use and oxidative stress/DNA damage.

RESULTS

Use of glucosamine (Ptrend: 0.01), chondroitin (Ptrend: 0.003), and fiber supplements (P: 0.01) was associated with reduced PGF2α concentrations, whereas CoQ10 supplementation was associated with reduced baseline DNA damage (P: 0.003).

CONCLUSIONS

Use of certain specialty supplements may be associated with reduced oxidative stress and DNA damage.

IMPACT

Further research is needed to evaluate the association between specialty supplement use and markers of oxidative stress and DNA damage.

Association between markers of obesity and progression from Barrett's esophagus to esophageal adenocarcinoma

BACKGROUND & AIMS

Individuals with Barrett's esophagus (BE) have an increased risk of developing esophageal adenocarcinoma (EA). Obesity contributes to the development of BE and its progression to cancer. We investigated the roles of obesity-induced hyperinsulinemia and dysregulation of adipokines in these processes.

METHODS

We measured fasting levels of glucose, insulin, leptin, and adiponectin in 392 patients enrolled in the Seattle Barrett's Esophagus Study. We calculated homeostatic model assessment scores (a measure of insulin sensitivity) and identified subjects with metabolic syndrome. We evaluated the association between these measures and the risk of EA using Cox regression models adjusted for known risk factors.

RESULTS

Increasing homeostatic model assessment scores were associated with an increasing risk for EA; the strongest association was observed within the first 3 years after participants entered the study (hazard ratio [HR], 2.45; 95% confidence interval [CI], 1.43-4.1; P trend = .001). Leptin level also was associated significantly with an increased risk of EA within 3 years (HR, 2.51; 95% CI, 1.09-5.81; P trend = .03) and 6 years (HR, 2.07; 95% CI, 1.01-4.26; P trend = .048) of baseline. The level of high-molecular-weight adiponectin had a nonlinear inverse association with risk of EA; the strongest associations were observed in the second tertile (HR, 0.34; 95% CI, 0.14-0.82). Metabolic syndrome was not associated with risk of EA.

CONCLUSIONS

Among patients with BE, increased levels of leptin and insulin resistance are associated with increased risk for EA, whereas increased levels of high-molecular-weight adiponectin is associated inversely with EA. These biomarkers might be used to determine cancer risk among patients with BE.

NSAIDs modulate clonal evolution in Barrett's esophagus

Cancer is considered an outcome of decades-long clonal evolution fueled by acquisition of somatic genomic abnormalities (SGAs). Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to reduce cancer risk, including risk of progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA). However, the cancer chemopreventive mechanisms of NSAIDs are not fully understood. We hypothesized that NSAIDs modulate clonal evolution by reducing SGA acquisition rate. We evaluated thirteen individuals with BE. Eleven had not used NSAIDs for 6.2±3.5 (mean±standard deviation) years and then began using NSAIDs for 5.6±2.7 years, whereas two had used NSAIDs for 3.3±1.4 years and then discontinued use for 7.9±0.7 years. 161 BE biopsies, collected at 5–8 time points over 6.4–19 years, were analyzed using 1Million-SNP arrays to detect SGAs. Even in the earliest biopsies there were many SGAs (284±246 in 10/13 and 1442±560 in 3/13 individuals) and in most individuals the number of SGAs changed little over time, with both increases and decreases in SGAs detected. The estimated SGA rate was 7.8 per genome per year (95% support interval [SI], 7.1–8.6) off-NSAIDs and 0.6 (95% SI 0.3–1.5) on-NSAIDs. Twelve individuals did not progress to EA. In ten we detected 279±86 SGAs affecting 53±30 Mb of the genome per biopsy per time point and in two we detected 1,463±375 SGAs affecting 180±100 Mb. In one individual who progressed to EA we detected a clone having 2,291±78 SGAs affecting 588±18 Mb of the genome at three time points in the last three of 11.4 years of follow-up. NSAIDs were associated with reduced rate of acquisition of SGAs in eleven of thirteen individuals. Barrett's cells maintained relative equilibrium level of SGAs over time with occasional punctuations by expansion of clones having massive amount of SGAs.

Cancer is a disease that develops over decades as result of accumulation of abnormalities in the genomes of otherwise normal cells. Cells in tumors compete for space and resources. Those cells able to survive the Darwinian struggle for existence within tissues progressively evolve uncontrolled growth and in some cases this results in cancer. Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) reduce death rate from multiple types of cancer by about 20%. However, the mechanisms by which NSAIDs act to prevent cancer are not fully understood. By examining thirteen individuals with Barrett's esophagus over time, we showed that the rate of accumulation of genomic abnormalities decreased when most individuals started taking NSAIDs. We also observed that, surprisingly, the number of abnormalities in the Barrett's tissues did not increase much over decades. However, in one individual who progressed to esophageal cancer, we observed massive genomic abnormalities affecting 19% of the genome. These findings suggest that NSAIDs may prevent cancer by reducing the accumulation of genomic abnormalities over time and that detection of stable versus unstable genomes may be used in the clinic to help manage treatment options in Barrett's esophagus.

Abstract 2561: MiRNA-related SNPs and risk of esophageal adenocarcinoma and Barrett's esophagus: post genome-wide association analysis in the BEACON consortium

The incidence of esophageal adenocarcinoma (EA) has increased significantly in recent decades. Although several major risk factors have been identified for EA and its precursor, Barrett's esophagus (BE), including reflux, Caucasian race, male gender, obesity, and smoking, only limited knowledge exists regarding the role of inherited genetic variation and its interplay with environmental factors. The Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) recently completed a genome-wide association study (GWAS) of 1,517 EA cases, 2,416 BE cases, and 2,187 controls. Using this dataset, we examined single nucleotide polymorphisms (SNPs) that potentially affect the biogenesis or biological activity of microRNAs (miRNAs), a class of small non-coding RNAs that regulate post-transcriptional gene expression and are deregulated in many cancers, including EA. Polymorphisms in three classes of genes were evaluated for their association with risk of EA or BE: 1) miRNA biogenesis genes (157 SNPs), 2) miRNA gene loci (234 SNPs), and 3) miRNA-targeted mRNAs (179 SNPs). 28 SNPs were significantly associated (P&lt;0.05) with EA, and 34 with BE. A polymorphism located in a predicted miRNA-138 binding site of the DNA repair gene XRCC1 (rs1799782) was associated with &gt;30% reduced risk of EA (OR 0.68, 95% CI 0.55-0.83), which remained significant after correction for multiple comparisons (adjusted P=0.04). This inverse association became more pronounced with increasing pack-years (P-interaction=0.02). Alterations in disease risk associated with other polymorphisms ranged from 10-40%. This study provides the most extensive assessment to date of miRNA-related SNPs in relation to risk of EA and BE and suggests that genetic variation in this pathway may influence disease susceptibility and interact with known risk factors.

Citation Format: Matthew F. Buas, Lynn Onstad, David Levine, Thomas L. Vaughan, David C. Whiteman, BEACON Consortium Investigators. MiRNA-related SNPs and risk of esophageal adenocarcinoma and Barrett's esophagus: post genome-wide association analysis in the BEACON consortium. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2561. doi:10.1158/1538-7445.AM2013-2561

Spectrum and risk of neoplasia in Werner syndrome: a systematic review

BACKGROUND

Werner syndrome (WS) is an autosomal recessive genetic instability and progeroid ('premature aging') syndrome which is associated with an elevated risk of cancer.

OBJECTIVES

Our study objectives were to characterize the spectrum of neoplasia in WS using a well-documented study population, and to estimate the type-specific risk of neoplasia in WS relative to the general population.

METHODS

We obtained case reports of neoplasms in WS patients through examining previous case series and reviews of WS, as well as through database searching in PubMed, Google Scholar, and J-EAST, a search engine for articles from Japan. We defined the spectrum (types and sites) of neoplasia in WS using all case reports, and were able to determine neoplasm type-specific risk in Japan WS patients by calculating standardized incidence and proportionate incidence ratios (SIR and SPIR, respectively) relative to Osaka Japan prefecture incidence rates.

RESULTS

We used a newly assembled study population of 189 WS patients with 248 neoplasms to define the spectrum of neoplasia in WS. The most frequent neoplasms in WS patients, representing 2/3 of all reports, were thyroid neoplasms, malignant melanoma, meningioma, soft tissue sarcomas, leukemia and pre-leukemic conditions of the bone marrow, and primary bone neoplasms. Cancer risk defined by SIRs was significantly elevated in Japan-resident WS patients for the six most frequent neoplasms except leukemia, ranging from 53.5-fold for melanoma of the skin (95% CI: 24.5, 101.6) to 8.9 (95% CI: 4.9, 15.0) for thyroid neoplasms. Cancer risk as defined by SPIR was also significantly elevated for the most common malignancies except leukemia.

CONCLUSIONS

WS confers a strong predisposition to several specific types of neoplasia. These results serve as a guide for WS clinical care, and for additional analyses to define the mechanistic basis for cancer in WS and the general population.

Use of glucosamine and chondroitin supplements and risk of colorectal cancer

PURPOSE

Glucosamine and chondroitin are non-vitamin, non-mineral supplements which have anti-inflammatory properties. These supplements are typically used for joint pain and osteoarthritis and are commonly taken as either glucosamine alone or glucosamine plus chondroitin. An exploratory analysis conducted within the VITamins And Lifestyle (VITAL) study observed any use of glucosamine and chondroitin to be associated with reduced risk of colorectal cancer (CRC) after 5 years of follow-up.

METHODS

With two additional years of follow-up, we have studied these associations in greater depth, including associations by frequency/duration of use and by formulation, and have evaluated whether observed associations are modified by factors associated with inflammation. Participants include 75,137 western Washington residents aged 50-76 who completed the mailed VITAL questionnaire between 2000 and 2002. Use of glucosamine and chondroitin was ascertained by questions about supplement use during the 10-year period prior to baseline, and participants were followed for CRC through 2008 (n = 557). Cox regression was used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs).

RESULTS

Persons reporting use of glucosamine + chondroitin on 4+ days/week for 3+ years had a non-statistically significant 45 % lower CRC risk than non-users (HR: 0.55; 95 % CI 0.30-1.01; p-trend: 0.16). This association varied by body mass index (p-interaction: 0.006), with inverse association observed among the overweight/obese (p-trend: 0.02), but not among the underweight/normal weight. Use of glucosamine alone was not significantly associated with CRC risk.

CONCLUSIONS

There is great need to identify safe and effective cancer preventive strategies, suggesting that glucosamine and chondroitin may merit further attention as a potential chemopreventive agent.

Genetic variation in C20orf54, PLCE1 and MUC1 and the risk of upper gastrointestinal cancers in Caucasian populations

Recently, two large genome-wide association studies, conducted in Chinese populations, have reported associations between upper gastrointestinal cancer and the rs2274223, rs13042395 and rs4072037 polymorphisms in PLCE1, C20orf54 and MUC1, respectively. We aimed to determine whether similar associations existed for Caucasian populations. We genotyped two population-based, case-control studies of upper gastrointestinal cancer; the first study included 290 gastric cancer (GC) cases and 376 controls and the second study included 306 GC cases, 107 oesophageal adenocarcinoma cancer cases, 52 oesphageal squamous cell cancer cases and 211 controls. Odds ratios (OR) and 95% confidence intervals (CIs) were computed from logistic models and adjusted for confounding variables. The rs4072037 polymorphism in MUC1 was associated with a reduced risk of GC of intestinal histological type (OR 0.4; 95% CI 0.2-0.9) and a reduced risk of oesophageal squamous cell cancer (OR 0.5; 95% CI 0.2-1.0), but not oesphageal adenocarcinoma. Similarly, rs2274223 in PLCE1 was associated with a reduced risk of oesophageal squamous cell cancer (OR 0.5; 95% CI 0.3-1.0), but not oesphageal adenocarcinoma. We observed no association between rs13042395 in Corf54 and the risk of gastric or oesphageal cancer in either of the two studies. Our findings for rs4072037 and the risk of GC are in agreement with one previous report for a Caucasian population. To the best of our knowledge, this is the first study to report an association between rs2274223 and rs4072037 and the risk of oesophageal squamous cell carcinoma in a Caucasian population.

The role of tobacco, alcohol, and obesity in neoplastic progression to esophageal adenocarcinoma: a prospective study of Barrett's esophagus

BACKGROUND

Esophageal adenocarcinoma (EA) incidence in many developed countries has increased dramatically over four decades, while survival remains poor. Persons with Barrett's esophagus (BE), who experience substantially elevated EA risk, are typically followed in surveillance involving periodic endoscopy with biopsies, although few progress to EA. No medical, surgical or lifestyle interventions have been proven to safely lower EA risk.

DESIGN

We investigated whether smoking, obesity or alcohol could predict progression to EA in a prospective cohort of 411 BE patients. Data were collected during personal interview. Adjusted hazard ratios (HR) were estimated using Cox regression.

RESULTS

39% had body mass index (BMI) over 30 and 64% had smoked cigarettes. Main analyses focused on those with at least 5 months of follow-up (33,635 person-months), in whom 45 developed EA. Risk increased by 3% per year of age (trend p-value 0.02), with approximate doubling of risk among males. EA risk increased with smoking pack-years (trend p-value 0.04) and duration (p-value 0.05). Compared to never-smokers, the HR for those in the highest pack-year tertile was 2.29 (95%CI 1.04-5.07). No association was found with alcohol or BMI, whereas a suggestion of increased risk was observed in those with higher waist-hip ratio, especially among males.

CONCLUSION

EA risk significantly increased with increasing age and cigarette exposure. Abdominal obesity, but not BMI, was associated with a modest increased risk. Continued follow-up of this and other cohorts is needed to precisely define these relationships so as to inform risk stratification and preventive interventions.

Epidemiology and risk factors for gastroesophageal junction tumors: understanding the rising incidence of this disease

Gastroesophageal (GE) junction carcinoma is a rare but often lethal condition with increasing importance as a public health problem in recent decades. Whereas diagnosis of this disease has been complicated historically by the lack of uniform classification standards, available data from the Surveillance, Epidemiology, and End Results cancer registry program in the United States show an approximate 2.5-fold increase in the incidence of GE junction adenocarcinoma from 1973 to 1992, with rates stabilizing in the past 2 decades. Similar proportional trends are observed among subgroups defined by race and gender, but rates are significantly higher in males relative to females, and in white males relative to black males. Smoking, obesity, and GE reflux disease are significant risk factors for GE junction adenocarcinoma, and may account for a substantial fraction of total disease burden. Infection with Helicobacter pylori has been associated with reduced incidence, and high dietary fiber intake has also been linked to lower disease risk. Ongoing studies continue to explore a potential role for nonsteroidal anti-inflammatory drugs in chemoprevention.

Body mass index in relation to oesophageal and oesophagogastric junction adenocarcinomas: a pooled analysis from the International BEACON Consortium

BACKGROUND

Previous studies suggest an association between obesity and oesophageal (OA) and oesophagogastric junction adenocarcinomas (OGJA). However, these studies have been limited in their ability to assess whether the effects of obesity vary by gender or by the presence of gastro-oesophageal reflux (GERD) symptoms.

METHODS

Individual participant data from 12 epidemiological studies (8 North American, 3 European and 1 Australian) comprising 1997 OA cases, 1900 OGJA cases and 11 159 control subjects were pooled. Logistic regression was used to estimate study-specific odds ratios (ORs) and 95% confidence intervals (CIs) for the association between body mass index (BMI, kg/m(2)) and the risk of OA and OGJA. Random-effects meta-analysis was used to combine these ORs. We also investigated effect modification and synergistic interaction of BMI with GERD symptoms and gender.

RESULTS

The association of OA and OGJA increased directly with increasing BMI (P for trend <0.001). Compared with individuals with a BMI <25, BMI ≥40 was associated with both OA (OR 4.76, 95% CI 2.96-7.66) and OGJA (OR 3.07, 95% CI 1.89-4.99). These associations were similar when stratified by gender and GERD symptoms. There was evidence for synergistic interaction between BMI and GERD symptoms in relation to OA/OGJA risk.

CONCLUSIONS

These data indicate that BMI is directly associated with OA and OGJA risk in both men and women and in those with and without GERD symptoms. Disentangling the relationship between BMI and GERD will be important for understanding preventive efforts for OA and OGJA.

Association between use of specialty dietary supplements and C-reactive protein concentrations

Laboratory evidence suggests that certain specialty dietary supplements have antiinflammatory properties, though evidence in humans remains limited. Data on a nationally representative sample of 9,947 adults from the 1999-2004 cycles of the National Health and Nutrition Examination Survey were used to assess the associations between specialty supplement use and inflammation, as measured by serum high-sensitivity C-reactive protein (hs-CRP) concentration. Using survey-weighted multivariate linear regression, significant reductions in hs-CRP concentrations were associated with regular use of glucosamine (17%, 95% confidence interval (CI): 7, 26), chondroitin (22%, 95% CI: 8, 33), and fish oil (16%, 95% CI: 0.3, 29). No associations were observed between hs-CRP concentration and regular use of supplements containing methylsulfonylmethane, garlic, ginkgo biloba, saw palmetto, or pycnogenol. These results suggest that glucosamine and chondroitin supplements are associated with reduced inflammation in humans and provide further evidence to support an inverse association between use of fish oil supplements and inflammation. It is important to further investigate the potential antiinflammatory role of these supplements, as there is a need to identify safe and effective ways to reduce inflammation and the burden of inflammation-related diseases such as cancer and cardiovascular disease.

Abstract 27: Telomere length in relation to the risk of Barrett's esophagus and esophageal adenocarcinoma

Background: Repeated injury of the esophagus by chronic gastroesophageal reflux (GER) is associated with the development of Barrett's esophagus (BE), a condition in which the squamous epithelium is replaced by a metaplastic columnar epithelium. A proportion of individuals diagnosed with BE progress to esophageal adenocarcinoma (EAC), which has considerably increased in incidence in many Western countries over the past four decades. Major risk factors associated with BE and EAC, such as obesity, smoking and gastroesophageal reflux (GER), are all contributors to the presence of chronic inflammation and oxidative damage. Unlike other areas of the chromosome that have effective repair systems to deal with oxidative damage, telomeres are not as well maintained and telomere length may reflect the impact of chronic inflammation. We investigated whether leukocyte telomere length was associated with BE or EAC risk compared to population-based controls in a pooled analysis of seven studies from the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON).

Methods: Telomere length was measured by quantitative-PCR using leukocyte DNA samples. Participants included 1,198 cases (395 with EAC, 403 with BE, 400 with GER) and 749 population-based controls. The association of telomere length (in tertiles) along the continuum of disease progression from GER to BE to EAC was calculated using study-specific odds ratios (OR) and 95% confidence intervals (CI) from logistic regression models, adjusted for age, sex, smoking status, alcohol consumption, BMI and education. Summary risk estimates were obtained using a random effects meta-analysis models.

Results: Shorter telomeres were associated with decreased risks of EAC (OR 0.84; 95% CI 0.47-1.48) and BE (OR 0.68; 95% CI 0.46-1.01), when compared to population-based controls, though not statistically significant. In addition, subjects with shorter telomeres were associated with a decreased risk of GER (OR 0.43; 95% CI 0.18-1.01), compared to population-based controls.

Conclusion: Telomere length may play a role in the progression from chronic reflux to BE and EAC.

Citation Format: E. Christina Persson, Linda M. Liao, Rosana Risques, Donna Prunkard, Carol Giffen, Wong-Ho Chow, Thomas L. Vaughan, on behalf of the Barrett's Esophagus, Adenocarcinoma Consortium (BEACON) Investigators. Telomere length in relation to the risk of Barrett's esophagus and esophageal adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Post-GWAS Horizons in Molecular Epidemiology: Digging Deeper into the Environment; 2012 Nov 11-14; Hollywood, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(11 Suppl):Abstract nr 27.

A clinical risk prediction model for Barrett esophagus

Barrett esophagus is the only known precursor to esophageal adenocarcinoma. As definitive diagnosis requires costly endoscopic investigation, we sought to develop a risk prediction model to aid in deciding which patients with gastroesophageal reflux symptoms to refer for endoscopic screening for Barrett esophagus. The study included data from patients with incident nondysplastic Barrett esophagus (n = 285) and endoscopy control patients with esophageal inflammatory changes without Barrett esophagus ("inflammation controls", n = 313). We used two phases of stepwise backwards logistic regression to identify the important predictors for Barrett esophagus in men and women separately: first, including all significant covariates from univariate analyses and then fitting non-significant covariates from univariate analyses to identify those effects detectable only after adjusting for other factors. The final model pooled these predictors and was externally validated for discrimination and calibration using data from a Barrett esophagus study conducted in western Washington State. The final risk model included terms for age, sex, smoking status, body mass index, highest level of education, and frequency of use of acid suppressant medications (area under the ROC curve, 0.70; 95%CI, 0.66-0.74). The model had moderate discrimination in the external dataset (area under the ROC curve, 0.61; 95%CI, 0.56-0.66). The model was well calibrated (Hosmer-Lemeshow test, P = 0.75), with predicted probability and observed risk highly correlated. The prediction model performed reasonably well and has the potential to be an effective and useful clinical tool in selecting patients with gastroesophageal reflux symptoms to refer for endoscopic screening for Barrett esophagus.

Selenium, selenoenzymes, oxidative stress and risk of neoplastic progression from Barrett's esophagus: results from biomarkers and genetic variants

Clinical trials have suggested a protective effect of selenium supplementation on the risk of esophageal cancer, which may be mediated through the antioxidant activity of selenoenzymes. We investigated whether serum selenium concentrations, selenoenzyme activity, oxidative stress and genetic variation in selenoenzymes were associated with the risk of neoplastic progression to esophageal adenocarcinoma (EA) and two intermediate endpoints, aneuploidy and tetraploidy. In this prospective cohort study, during an average follow-up of 7.3 years, 47 EA cases, 41 aneuploidy cases and 51 tetraploidy cases accrued among 361 participants from the Seattle Barrett's Esophagus Research Study who were free of EA at the time of blood draw and had at least one follow-up visit. Development to EA was assessed histologically and aneuploidy and tetraploidy by DNA content flow cytometry. Serum selenium concentrations were measured using atomic absorption spectrometry, activity of glutathione peroxidase (GPX) 1 and GPX3 by substrate-specific coupled test procedures, selenoprotein P (SEPP1) concentrations and protein carbonyl content by ELISA method and malondialdehyde concentrations by HPLC. Genetic variants in GPX1-4 and SEPP1 were genotyped. Serum selenium was not associated with the risk of neoplastic progression to EA, aneuploidy or tetraploidy (P for trend = 0.25 to 0.85). SEPP1 concentrations were positively associated with the risk of EA [hazard ratio (HR) = 3.95, 95% confidence intervals (CI) = 1.42-10.97 comparing the third tertile with the first] and with aneuploidy (HR = 6.53, 95% CI = 1.31-32.58), but not selenoenzyme activity or oxidative stress markers. No genetic variants, overall, were associated with the risk of neoplastic progression to EA (global p = 0.12-0.69). Our results do not support a protective effect of selenium on risk of neoplastic progression to EA. Our study is the first to report positive associations of plasma SEPP1 concentrations with the risk of EA and aneuploidy, which warrants further investigation.

The importance of exposure rate on odds ratios by cigarette smoking and alcohol consumption for esophageal adenocarcinoma and squamous cell carcinoma in the Barrett's Esophagus and Esophageal Adenocarcinoma Consortium

BACKGROUND

Cigarette smoking is associated with esophageal adenocarcinoma (EAC), esophagogastric junctional adenocarcinoma (EGJA) and esophageal squamous cell carcinoma (ESCC), and alcohol consumption with ESCC. However, no analyses have examined how delivery rate modifies the strength of odds ratio (OR) trends with total exposure, i.e., the impact on the OR for a fixed total exposure of high exposure rate for short duration compared with low exposure rate for long duration.

METHODS

The authors pooled data from 12 case-control studies from the Barrett's Esophagus and Esophageal Adenocarcinoma Consortium (BEACON), including 1242 (EAC), 1263 (EGJA) and 954 (ESCC) cases and 7053 controls, modeled joint ORs for cumulative exposure and exposure rate for cigarette smoking and alcohol consumption, and evaluated effect modification by sex, body mass index (BMI), age and self-reported acid reflux.

RESULTS

For smoking, all sites exhibited inverse delivery rate effects, whereby ORs with pack-years increased, but trends weakened with increasing cigarettes/day. None of the examined factors modified associations, except for ESCC where younger ages at diagnosis enhanced smoking effects (P<0.01). For EAC and EGJA, ORs with drink-years exhibited inverse associations in <5 drinks/day consumers and no association in heavier consumers. For ESCC, ORs with drink-years increased, with trends strengthening with greater drinks/day. There was no significant effect modification, except for EAC and EGJA where acid reflux mitigated the inverse associations (P=0.02). For ESCC, younger ages at diagnosis enhanced drinking-related ORs (P<0.01).

CONCLUSIONS

Patterns of ORs by pack-years and drink-years, delivery rate effects and effect modifiers revealed common as well as distinct etiologic elements for these diseases.

Cigarette smoking increases risk of Barrett's esophagus: an analysis of the Barrett's and Esophageal Adenocarcinoma Consortium

BACKGROUND & AIMS

Cigarette smoking has been implicated in the etiology of esophageal adenocarcinoma, but it is not clear if smoking is a risk factor for Barrett's esophagus. We investigated whether tobacco smoking and other factors increase risk for Barrett's esophagus.

METHODS

We analyzed data from 5 case-control studies included in the international Barrett's and Esophageal Adenocarcinoma Consortium. We compared data from subjects with Barrett's esophagus (n = 1059) with those from subjects with gastroesophageal reflux disease (gastroesophageal reflux disease controls, n = 1332), and population-based controls (n = 1143), using multivariable logistic regression models to test associations with cigarette smoking. We also tested whether cigarette smoking has synergistic effects with other exposures, which might further increase risk for Barrett's esophagus.

RESULTS

Subjects with Barrett's esophagus were significantly more likely to have ever smoked cigarettes than the population-based controls (odds ratio [OR] = 1.67; 95% confidence interval [CI]: 1.04-2.67) or gastroesophageal reflux disease controls (OR = 1.61; 95% CI: 1.33-1.96). Increasing pack-years of smoking increased the risk for Barrett's esophagus. There was evidence of a synergy between ever-smoking and heartburn or regurgitation; the attributable proportion of disease among individuals who ever smoked and had heartburn or regurgitation was estimated to be 0.39 (95% CI: 0.25-0.52).

CONCLUSIONS

Cigarette smoking is a risk factor for Barrett's esophagus. The association was strengthened with increased exposure to smoking until ∼20 pack-years, when it began to plateau. Smoking has synergistic effects with heartburn or regurgitation, indicating that there are various pathways by which tobacco smoking might contribute to development of Barrett's esophagus.