Sa1917

Epidemiology of Noncardia Gastric Adenocarcinoma in the United StatesBarry Schlansky, Amnon Sonnenberg

Background and Aims. Although adenocarcinoma of the cardia (ICD-9 code 151.0) andadenocarcinoma of the stomach (ICD-9 codes 151.1-151.9) are two clearly distinct diseases,in epidemiologic statistics they are frequently grouped together. The aim of this study wasto describe the current epidemiology of noncardia gastric cancer (GCA) in the United States.Methods. Three national databases were utilized to analyze GCA incidence, hospitalization,and mortality in the U.S. between 1997 and 2008. The Surveillance, Epidemiology, andEnd Results (SEER) database was used for incidence data, the Healthcare Costs and UtilizationProject (HCUP) for hospitalization data, and theWide-Ranging Online Data for EpidemiologicResearch (WONDER) for mortality data. Annual population estimates were obtained fromthe U.S. Census Bureau. Population-based incidence, hospitalization, and mortality rateswere adjusted to the U.S. 2000 population using the direct standardization method. Oddsratios (OR) and their 95% confidence intervals (CI) were calculated, using the Mantel-Haenszel method to adjust for confounding variables. Categorical variables were comparedwith Chi-square analysis. Results. Annually, GCA was associated with 19,090 incidentcases, 17,284 hospitalizations for first-listed diagnoses, 31,353 hospitalizations for all-listeddiagnoses, and 11,561 deaths. The incidence of GCA was greater in men than women (OR=1.56, CI 1.53-1.59) and non-white than white race (OR=2.38, CI 2.33-2.43). Hospitalizationfor GCA was more common in men than women (OR=1.82, CI 1.81-1.83) and non-whitethan white race (OR=2.13, CI 2.10-2.15). Mortality from GCA was more common in menthan women (OR=1.83, CI 1.81-1.86) and non-white than white race (OR=2.23, CI 2.20-2.26). In all three databases, GCA rates showed a marked age-dependent rise, with thehighest rates observed in the oldest age group, 85+ (p<0.001). Hospitalization and mortalityof GCA were greatest in the Northeast region of the U.S., followed by the South, West, andMidwest regions (p<0.001). Conclusions. Similar epidemiologic patterns were found amongthree different national databases. Older age, male gender, non-white race, and residencein the Northeast region of the U.S. were associated with an increased risk for noncardiagastric adenocarcinoma. These patterns may partly reflect underlying variations in exposureto H. pylori infection.

Sa1918

Anthropometrics and Colorectal Adenoma Risk Among Older WomenAmy S. Oxentenko, Robert Vierkant, Alice Wang, Aaron Folsom, Beth A. Virnig, James R.Cerhan, Paul J. Limburg

Background: Obesity is a controversial risk factor for colorectal cancer among older women.To date, relatively few studies have reported associations between anthropometric parametersand premalignant colorectal adenomas (CRAs) in this population. To address this knowledgegap, we evaluated height, weight, body mass index (BMI) and waist-to-hip ratio (WHR) aspredictors of CRA risk among subjects enrolled in the Iowa Women's Health Study (IWHS).Methods: The IWHS is a prospective cohort study of cancer and related endpoints amongrandomly selected Iowa women, ages 55-69 years of age and holding a valid drivers licenseat enrollment (1986). Height and weight were self-reported, while waist and hip circumfer-ences were measured using a paper tape, by IWHS subjects at baseline. BMI (kg/m2) andWHR were derived from these variables. CRAs were identified from Medicare data for 1993-2004 (hospitalization, outpatient and carrier files), using ICD-9 codes 211.3 and 211.4.Exclusion criteria were defined as: never enrolled in both parts A and B of Medicare for atleast one month on or after January 1, 1993; no response to 1992 IWHS follow-up question-naire; prior malignancy (except non-melanoma skin cancer) or CRA; < 1 year of follow-up;or incomplete anthropometric data. Height, weight, BMI andWHRwere analyzed by quartiles.Multivariate Cox regression models were fit to estimate relative risks (RRs) and 95% confid-ence intervals (CIs). Results: Complete anthropometric and CRA data were available for25,865 subjects. During 224,564 person-years of follow-up, 5,460 women were identifiedwith at least one newly diagnosed CRA. Height, weight, BMI and WHR were all positivelyassociated with CRA risk (p ≤ 0.001 for each variable; see Table). Conclusions: AmongIWHS subjects, multiple baseline anthropometric parameters were associated with increasedCRA risk. These data support body size as a potentially modifiable risk factor for premalignantcolorectal neoplaisa in older women.

S-347 AGA Abstracts

*RRs and 95% CIs adjusted for: age, smoking status, physical activity, exogenous estrogenuse, age at menopause, history of diabetes mellitus, and daily intakes of total energy, totalfat, red meat, fruits and vegetables, calcium, folate, vitamin E, and alcohol.

Sa1919

Low Serum Ghrelin is Associated With an Increased Risk of GastricAdenocarcinomaGwen A. Murphy, Farin Kamangar, Sanford M. Dawsey, Frank Z. Stanczyk, Stephanie J.Weinstein, Philip R. Taylor, Jarmo Virtamo, Christian C. Abnet, Demetrius Albanes, NealD. Freedman

Background: Cancers of the upper gastrointestinal tract remain a significant cause ofmorbidityand mortality. Ghrelin is a hormone produced in the oxyntic glands of the stomach andit's concentration is known to decrease significantly under conditions of inflammation andatrophy, however, it's role in the etiology of gastric cancer has not been explored. To examinethe relationship between serum ghrelin concentration and risk of gastric and esophagealcancers we conducted a nested case-control study within the Alpha-Tocopherol, Beta-Carot-ene Cancer Prevention (ATBC) Study cohort, in Finland. Methods: 82 esophageal squamouscell carcinomas (ESCC), 86 gastric cardia adenocarcinomas (GCA) and 174 gastric non-cardia adenocarcinomas (GNCA) were matched (1:1) by age and date of blood draw to thecontrols from the ATBC study. Odds ratios (OR) and 95% confidence intervals (95%CI) were calculated using unconditional logistic regression with adjustment for potentialconfounders. Results: Lower concentrations of serum ghrelin were significantly associatedwith an increased risk of GCA and GNCA. For those individuals in the lowest quartile ofserum ghrelin, compared to those in the highest, the multivariate ORs were 6.11 for GCA(95% CI: 1.41, 26.46) and 6.54 for GNCA (95% CI: 2.69, 15.90). These associations weredose dependent (P for trend = 0.008 and <0.0001, respectively) and independent of theeffect of low pepsinogen/atrophy and Helicobacter pylori infection, the significance of theseassociations remained following exclusion of individuals who developed cancer within thefirst 5 years of the study. The crude association noted for low serum ghrelin and ESCC didnot survive adjustment for potential confounders. Specifically, the addition of low serumpepsinogen I to the model nullified the significance of the association between low serumghrelin and increased risk of ESCC. Conclusion: Lower serum concentrations of ghrelinwere associated with a significantly increased risk of GCA and GNCA. The possible etiologicrole for ghrelin in gastric cancer should be investigated in future studies.

Sa1920

Biomarkers of Oxidative Stress and Risk of Colorectal Cancer: A Cohort-Nested Case-Control Study in the EPIC DatabaseAnke M. Leufkens, Fränzel J. van Duijnhoven, Sjoukje Woudt, Peter D. Siersema,Hendrik B. Bueno-de-Mesquita

Introduction: Oxidative stress is associated with the development of cancer. Prospectiveevidence for an association between oxidative stress biomarkers and risk of colorectal cancer(CRC) is not present. Aim: To investigate an association between blood concentrations ofreactive oxygen and antioxidant capacity as indicators of oxidative stress and CRC. Methods:Pre-diagnostic serum levels of Reactive Oxygen Metabolites (ROM) and Ferric ReducingAbility of Plasma (FRAP) were studied in relation to CRC risk in a nested case-control studywithin the European Prospective Investigation into Cancer and nutrition (EPIC) cohort. Atotal of 1,230 CRC cases were matched to 1,230 controls (median follow-up 3.8 years).Incidence Rate Ratios (IRRs) and 95% confidence intervals (95%CI) were estimated usingmultivariate conditional logistic regression analysis. Results: ROM was associated with theoverall risk of CRC (adjusted IRR for the highest compared to the lowest tertile 1.91, 95%CI1.47-2.48) and with subsites of CRC (adjusted IRRs between 1.69 and 2.31, p <0.05). When

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