Mo1136

Colorectal Cancer Under Age 50 Years: a Surveillance Epidemiology and EndResults Based Analysis of CRC Incidence and Mortality in Young AdultsOverall, Stratified by Sex, and Relative to Other Common CancersAbhishek Bhandari, Elena Martinez, Samir Gupta

Background: Colorectal cancer (CRC) is a leading cause of cancer death worldwide, account-ing for 608,000 deaths in 2008 (World Health Organization, 2013). Largely as a result ofscreening, CRC incidence is declining, but the trend is restricted to individuals age >50years (Edwards BK 2010). Indeed, CRC incidence is increasing among individuals youngerthan 50 (World Health Organization, 2013; Siegel RL 2009). Setting public health prioritiesfor screening research and interventions requires understanding absolute rates of CRCincidence and mortality, and assessment of CRC incidence and mortality relative to othercancer types. Our aim was to use population-based cancer registry data to contrast CRCincidence and mortality relative to other common cancers, overall, and by sex. Methods:We utilized the Surveillance, Epidemiology, and End Results [SEER] Cancer Query systemto obtain cancer incidence and mortality data from the SEER Registry 2001- 2010. Tocompare cancer site-specific mortality rates, we extracted age-adjusted mortality per 100,000for individuals aged 20-44 years. To compare cancer site-specific incidence rates, we extractedage-specific incidence per 100,000 for individuals aged 15-49 years. We present mortalityand incidence data for the common young-onset cancers overall as well as stratified by sex.Results: Figure 1 demonstrates that CRC is the 3rd leading cause of cancer death amongyoung adults, after breast and lung cancer, at 1.67 cases per 100,000. Among males underage 45 yrs, CRC was the 2nd leading cause of cancer death, at 1.82 cases per 100,000, 2ndonly to lung cancer. Among females under age 45 yrs, CRC was the 4th leading cause ofcancer death, at 1.51 per 10000, behind breast, lung, and cervical cancer, respectively. Sex-specific differences in young onset CRC incidence patterns were noted. Among males, CRCbecame the 2nd most incident cancer after age 30, with 4.9, 9.0, 16.4, and 30.8 cases per100,000 for ages 30-34, 35-39, 40-44, and 45-49 yrs, respectively (Figure 2A). Amongfemales, CRC incidence patterns were similar to males after age 30, with 4.2, 7.6, 15.3, and25.9 cases per 100,000 for ages 30-34, 35-39, 40-44, and 45-49 yrs, respectively (Figure2B). However, among females, CRC incidence was dwarfed by breast cancer incidenceoverall, and less distinct from other cancers as compared to males. Conclusions: CRC is afrequent cause of cancer incidence and mortality among young adults in the U.S. Given theoverall incidence and mortality of CRC among young adults, and previously reported increas-ing trends in incidence, and availability of effective screening tests for CRC, new strategiesfor identifying young adults at risk for CRC who may be candidates for screening shouldbe developed.

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Figure 1: Age-adjusted mortality per 100,000 for males and females combined, SEER 2001to 2010

Figure 2: Age-specific CRC incidence among males (Figure 2A) and females (Figure 2B) age15 to 49 relative to other common cancers, SEER 2001 to 2010

Mo1137

Rectal Cancer: Characteristics and Survival Rates of Young vs. OldShams Mistry, Charles Andrew T. Chacko, Jill Gernand, Harish Madala, AlMarieGraceLogrono, Radhika Kakarala

Introduction: Rectal cancer is detected at a later stage in younger patients (YP) (< 50) dueto lack of screening in this age group. There has been an increased incidence of rectal cancerin YP, but they are underrepresented in research studies. The aim of our study is to comparecharacteristics of rectal cancer and survival outcome in YPs (18-49 years) vs older patients(50+) using the Surveillance, Epidemiology, and End Results (SEER) database. Methods:We analyzed a retrospective cohort of patients diagnosed with rectal cancer in the SEERnational cancer registry from 1991 through 2010. This National Cancer Institute database isa cancer registry covering approximately 26% of the US population across several geographicregions. It is the largest publicly available domestic cancer database. Using the SEER database,

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swe reviewed patients > 18 years of age with rectal adenocarcinoma from 1991-2010. Continu-ous and categorical variables are reported using mean (SD), proportions, and percentages.Univariate analysis was done using T-test and Chi-square tests respectively. MultivariateCox regression analysis was used to evaluate risk adjusted outcomes and to predict thehazard of dying. Kaplan Meier method was used to estimate the survival function. Results:We included 102,167 patients in our study. YPs with rectal carcinoma were more likely tobe African American (11.9% vs 8.8%; p<0.001), Hispanic (13.3% vs 8.3%; p<0.001) andAsian (10.9% vs 8.3%; p<0.001) as compared to the older age group. YPs were morelikely to present with distant metastasis (16.7% vs 13.4%; p<0.001) and had more poorlydifferentiated tumors (13.3 % vs 12.1%; p< 0.001). YPs also received more cancer directedsurgery (84 % vs 80%; p<0.001) and post-operative radiation (52% vs 39.8; p<0.001)compared to their older counterpart. In contrast to previous studies the five year survivalwas better for younger patients (74.3% vs 70.7%; p<0.001{table 1}). After controlling forgender, race, marital status, grade, stage, cancer specific surgery and post-operative radiation,multivariate Cox regression analysis revealed that age is an independent predictor of death,and younger patients with rectal cancer had a lower risk of dying (HR 0.693; p<0.001)Conclusion: In previous studies younger patients with rectal cancer were found to havepoorer or equivalent survival compared to older patients. In contrast, our study shows thatyoung patients less than 50 years of age, have advanced stage rectal cancer at diagnosis buthave better survival.Table 1: Five-year relative survival for rectal cancer patients

Mo1138

Erythrocyte Membrane Phospholipid Fatty Acid Concentrations and ColorectalAdenomas: A Case Control in TennesseeSamara Rifkin, Martha J. Shrubsole, Qiuyin Cai, Walter E. Smalley, Reid Ness, Larry L.Swift, Wei Zheng, Harvey Murff

Background: Polyunsaturated acids levels have been associated with colorectal cancer. Animalmodels suggest that n-3 polyunsaturated fatty acids (PUFA) may protect against cancer,whereas n-6 PUFAs may promote oncogenesis. Human studies have been inconclusive. Fewstudies have incorporated biomarkers of fatty acids intake into the study design and thosethat have are limited by small sample sizes. We evaluated the association between adenomasand advanced adenomas using the Tennessee Colorectal Polyp Study (TCPS), the largest,colonoscopy-based case-control study of incident adenomas within the United States. Meth-ods: We conducted a case-control study of 700 non-advanced adenoma cases, 350 advancedadenoma cases, and 1050 polyp-free controls. Erythrocyte membrane phospholipid fattyacid concentrations were determined by gas chromatography. Unconditional logistic regres-sion was used to calculate adjusted ORs for risk of colorectal adenomas with concentrationsof fatty acids, for advanced and all adenomas. Results: Associations were stronger amongall adenomas compared to only advanced adenomas. Contrary to previous studies, eicosapen-taenoic (EPA) was associated with increased risk of all adenomas [OR Q3vsQ1 = 1.40 (1.07,1.82)], but the association disappeared comparing the highest with the lowest quartile. Oleicacid was associated with an increased risk of all adenomas [OR Q4vsQ1 = 1.41 (1.04, 1.92)].Docosapentaenoic (DPA) was inversely associated with risk of all adenomas [OR Q4vsQ10.69 (0.51, 0.93)]. Increased levels of arachidonic acid were associated with all adenomas,but only trended toward significance [OR Q4vsQ1 1.54 (0.93, 2.53). Combined n-3 PUFAswere negatively associated with all adenomas [OR Q4vsQ1 0.75 (0.55, 1.03)], but also onlytrended toward significance. Conclusion: DPA and combined n-3 PUFAs were inverselyassociated with risk of all adenomas, however contrary to expectation EPA may be associatedwith an increased risk. Oleic acid and arachidonic acid were positively associated with alladenomas, although combined n-6 PUFAs were not.

Mo1139

Do Survival Outcomes Differ Between and Within Left and Right-Sided ColonCancers? A Population-Based StudyXi E. Zheng

Background: Despite declining mortality of colon cancer since the advent of screeningcolonoscopy, the incidence and mortality appear to shift towards right-sided colon. Tradition-ally the splenic flexure, descending and sigmoid colon are considered left-side, while theremaining segments excluding appendix are right-side of the colon. It remains unclearwhether the survival vary by tumor location in specific segments of the colon. Methods:We examined the relationships between colon cancer locations and cancer-specific andoverall survivals in a longitudinal population-based database. Subjects who were diagnosedwith primary colon adenocarcinoma from 2005 and 2010 were selected from the 18 RegistriesSurveillance Epidemiology and End Results database. Patient demographics, tumor- andtherapy-related variables were also extracted. Multivariate logistic and Cox proportionalhazards regression analyses were performed to evaluate the factors associated with the tumorlocation and the effects of tumor location on survivals using STATA. Results: Of 102,164patients diagnosed with primary adenocarcinoma of the colon between 2005 and 2010,58% had right-sided cancer. The tumors mostly commonly originated from the sigmoidcolon (32%), cecum (24%), ascending colon (20%), followed by transverse, descendingcolon, hepatic and splenic flexure (< 10% for each colon segment). Right-sided (cecum totransverse) cancers affected older, female patients, involved more lymph node metastasesand less distant metastases, and had higher rate of surgical intervention and lower rate ofadjuvant radiation therapy, as compared to left-sided cancers (p<0.001). Among all colon

S-568AGA Abstracts

segments, cancers from the cecum, ascending colon, hepatic flexure, transverse colon andsplenic flexure were associated with a HR of 1.16-1.36 for cancer-specific mortality and HRof 1.15-1.27 for overall mortality (p < 0.05), compared to cancers from the sigmoid colon,after controlling for all potential covariates. There was no difference in survival for cancersof the descending vs sigmoid colons and within the right-side colon. Overall, right-sidedcolon cancer was associated with 20% higher mortality relative to left-sided cancer afteradjusting for demographics and tumor stages, histologic grade, size, surgery, lymph nodesexamined and radiation therapy. Subgroup analyses resulted in the similar left-right survivaldifferences. Conclusions: Worse survivals of right-sided vs left-sided colon cancer wereconsistent across all colon segments except for splenic flexure, and across all ethnic groupsand tumor stages. It might be reasonable to group cancers at the splenic flexure into right-sided colon considering their survival disadvantage compared to the sigmoid and descendingcolon. Future studies on genetic and environmental factors controlling the location-specifictumorigenesis are warranted.

Mo1140

Prognostic Significance of Deprivation in Upper Gastrointestinal CancerPaul A. Blake, Charlotte E. Thomas, Alex Karran, David S. Chan, Guy Blackshaw,Geoffrey W. Clark, Timothy Havard, Xavier Escofet, Ashley Roberts, Wyn G. Lewis

Objective. To determine the influence of the Index of Multiple Deprivation (IMD) and healthdeprivation (HD) on upper gastrointestinal (UGI) cancer outcome. Design. 1185 consecutivepatients (697 esophageal, 488 gastric cancer) were studied prospectively and deprivationscores calculated using the IMD of Welsh Government. Primary outcome measure wassurvival from diagnosis. Results. Open and close laparotomy for all surgical patients wascommoner in patients residing in deprived geographical areas with a 6.5% open and closerate in the least deprived IMD quintile versus 13.5% in the most deprived quintile (p<0.0001).On post-operative histopathology, IMD was associated with pT (R=-0.146, p=0.043), pN(R=-0.158, p=0.029), and pM stage (R=-0.189, p=0.016). On univariate analysis survivalwas associated with esophageal versus gastric tumour site (p=0.028), histopathological celltype (p<0.0001), age (p<0.0001), radiological (r) TNM stage (p<0.0001), radical treatmentintent (p<0.0001), IMD (p<0.0001), and HD (p<0.0001). On multivariate analysis of allpatients, age (HR 1.021, 95% CI 1.014-1.028, p<0.0001), rTNM stage (HR 1.559, 95% CI1.427-1.704 p<0.0001), radical treatment intent (HR 0.338, 95% CI 0.274-0.418, p<0.0001),and IMD rank (HR 1.000, 95% CI, 1.000-1.000, p=0.084) were associated with durationof survival. Median (1 and 2 year) survival for patients residing in the most deprived quintilewas 9months (36%, 22%) compared with 11 months (45%, 28%) for patients residing inthe least deprived quintile. Conclusion. Deprivation is an important, but not independent,prognostic indicator in UGI cancer.

Mo1141

Association of Right-Sided Colorectal Cancer and Ulcerative Colitis WithEscherichia coli Strains of Phylogenetic Group B2, Which Harbour Genotoxic"PKS" IslandDarina Kohoutova, David Smajs, Michal Cihak, Jan Bures

Objectives: Precise aetiology and pathogenesis of right-sided colorectal cancer (CRC) andCRC associated with inflammatory bowel disease is still poorly understood. Right-sided andleft-sided CRC differs significantly from molecular, histopathological and clinical point ofview. The overall prevalence of CRC in patients with ulcerative colitis is higher whencompared to patients with Crohn's disease. Large intestinal microbiota play an importantrole in the aetiology and pathogenesis of CRC. Escherichia coli strains of genotype B2harbour the "pks" genomic island, which encodes colibactin, a polyketide-peptide genotoxin.Colibactin is capable to affect the host immune response and causes DNA double-strandbreaks. Therefore, colon colonization with Escherichia coli genotype B2 could contributeto the development of CRC. Methods: Mucosal biopsies were taken in the caecum / ascendingcolon, transverse colon and rectum within the colonoscopy in patients with right-sided CRC(12 biopsies, 4 patients, 3 men, 1 woman, mean age 68±16), left-sided CRC (78 biopsies,26 patients, 20 men, 6 women, mean age 66±11), ulcerative colitis (30 biopsies, 10 patients,5 men, 5 women, mean age 38±12), Crohn's disease (60 biopsies, 20 patients, 8 men, 12women, mean age 34±15) and in healthy controls (population with average risk for colorectalcancer with normal endoscopic findings and with negative history of colorectal cancer orinflammatory bowel disease; 60 biopsies, 20 patients, 9 men, 11 women, mean age 55±15).After appropriate microbiological culture genotypes of Escherichia coli were investigated byPCR methods. Results: Microbiological assessment and PCR investigation were carried outfrom 240 biopsy samples. Statistically significant difference in the frequency of Escherichiacoli genotype B2 was found out between patients with right-sided CRC and patients withleft-sided CRC (9/12 (75%) vs. 32/78 (41%); p=0.028). Statistically significant differencein the frequency of Escherichia coli genotype B2 was found between patients with ulcerativecolitis and patients with Crohn's disease (19/30 (63%) vs. 24/60 (40%); p=0.037). Escherichiacoli strains of genotype B2 were found in 40% (24/60) biopsy specimens of healthy controls.Conclusions: Escherichia coli genotype B2 with its genotoxic "pks" island was found morefrequently in patients with right-sided CRC and patients with ulcerative colitis. Contributionof large intestinal microbiota to the pathogenesis of CRC is indisputable.

Mo1142

Combination of Triple Therapy and Chronic Proton Pump Inhibitor MayAttenuate the Risk of Colonic Adenomatous Polyps in Helicobacter pyloriInfectionRina Zuniga, Josef Bautista, Susan E. Williams, Alexander Sy, Katherine Sapra

Background: Epidemiologic data about the role of Helicobacter pylori (H. pylori) infectionand chronic proton pump inhibitor (PPI) use in the development of colonic adenomatouspolyps are conflicting. This study aims to determine any association between H. pyloriinfection and the risk of colonic adenomatous polyps and to explore whether triple therapy