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753 Stool DNA Screening of Colorectal Neoplasia: Improved Adenoma Detection By Novel Digital Melt Curve Assay
750
AGA Abstracts
Identification of Inherited Predisposition to Colonic Neoplasia Through Partial Wave Spectroscopic Analysis of the Microscopically Normal Colonic Epithelium Hemant K. Roy, Hariharan Subramanian, Prabhakar Pradhan, Henry T. Lynch, David Weinberg, Zvezdana Bogojevic, Nahla Hasabou, Jennifer Koetsier, Ramesh K. Wali, Stephen J. Lanspa, Michael J. Goldberg, Dhananjay Kunte, Vadim Backman While familial risk comprises ~20-30% of all colorectal cancers (CRC), in most cases the genetic etiology is not readily identifiable. Thus, counselling CRC-prone families members is not based on individized risk assessment (e.g. one size fits all approach). Our group has developed novel light scattering technologies such as partial wave spectroscopy (PWS)to quantitate nanoscale architecture. We have noted that pre-dysplastic mucosal optical signatures provided a highly sensitive means of detecting CRC risk in experimental models(Gastro 2004, CEBP 2005, Clin Cancer Res 2006). Moreover, the PWS parameter, disorder strength (Ld), was markedly elevated in the endoscopically normal rectal mucosa of patients harboring adenomas (i.e. “field effect”). We now explore whether colonic Ld could detect a genetic predisposition to CRC. Methods: Animal studies: MIN (murine model of FAP with APC gene mutation) or age-matched wildtype mice were euthanized and had intestinal brushings taken of neoplasia-free areas Human Studies 35 patients with HNPCC mutation-confirmed (hMLH-1&hMSH-2),adenoma-free or controls (age-matched but no personal/family history) had rectal brushings taken during colonoscopy. PWS analysis: Ld and standard deviation of Ld (SDLd) were calculated by investigator blinded to clinical findings Results Ld was markedly elevated in the normal mucosa of germline carriers when compared to controls (figure). This, coupled with SDLd, allowed clear descrimination between cases and controls(both murine and human model. Conclusions: Ld and SDLd from the visually normal mucosa identified APC and hMLH1/hMSH2 mutations prior to phenotype development. Thus, probing nanoscale perturbations from readily accessible mucosa (e.g. rectum) may provide a modality for determing both the carriage of these syndromic mutations and possibly allow detection of the more common lower penetrant CRC risk genes.
752 Fluorodeoxyglucose-Positron Emission Tomography Scan (FDG-PET Scan) in the Diagnosis of Colorectal Cancer Recurrence Céline Deleau, Bruno Buecher, Caroline Rousseau, Françoise Kraeber-Bodéré, Stanislas Bruley des Varannes, Jean Paul Galmiche, Tamara Matysiak-Budnik Introduction: Early detection is an essential prognostic factor in colorectal cancer (CRC) recurrence. It has been suggested that FDG-PET Scan is more sensitive than computed tomography (CT) in the detection of early peritoneal carcinomatosis, lymph node metastases or neoplastic components within residual mass. Aims and methods: Our aim was to evaluate diagnostic performances of FDG-PET Scan in the detection of CRC recurrence and to determine the impact of FDG-PET Scan on clinical management of the patients. All CT and FDG-PET Scans performed in a single department between 2002 and 2006 for suspicion of CRC recurrence were analyzed retrospectively. All detected lesions were characterized according to their number, size, and anatomical localization. The lesions stable on at least two consecutives examinations were considered negative. The gold standard was histology or radiological follow-up according to the RECIST criteria of progression. Diagnostic sensitivity was calculated globally and with respect to the localization and the results of carcinoembryonic antigen (CEA) dosage. Diagnostic and therapeutic impact of FDG-PET Scan was evaluated by comparing pre- and post-FDG-PET Scan strategies. Results: One hundred and seven FDG-PET Scans, performed in 92 patients, were analyzed. One hundred eighty lesions (57 hepatic and 123 extrahepatic) were identified. Serum CEA dosage was obtained in 79/ 106 cases and was normal in 61% of patients and elevated in 39% of patients. Out of 186 lesions identified by FDG-PET Scan, 172 were true positive and 14 false positive. Out of 119 lesions identified by CT, 98 were true positive and 21 false positive. Ten patients were free of relapse. The global sensitivity for the detection of neoplastic lesions was of 95.6% for FDG-PET Scan and 55.1% for CT. In patients with elevated CEA, this value was of 96.8% for FDG-PET Scan and 49.2% for CT. Sensitivity of FDG-PET Scan for the detection of extrahepatic abdominal metastases was 100%. As compared to CT, FDG-PET Scan had a diagnostic impact in 58% of cases and led to modification of therapy in 33% of patients (avoidance of surgery in 8 patients, earlier decision of curative treatment in 6 patients, and earlier instauration of palliative chemotherapy in 7 cases). Conclusions: FDG-PET Scan is more sensitive than CT for diagnosis of CRC recurrence, in particular in patients with elevated CEA and in case of extra-hepatic abdominal metastases. FDG-PET Scan results can modify the management in about one third of the patients and thus should be proposed as a routine examination in patients with suspicion of CRC recurrence.
751 Prediction of Colonic Neoplasia Through Spectral Marker Analysis from the Endoscopically Normal Rectum: An Ex Vivo and In Vivo Study Hemant K. Roy, Vladimir Turzhitsky, Andrew Gomes, Michael J. Goldberg, Jeremy D. Rogers, Young L. Kim, Tat-Kin Tsang, Dhiren Shah, Monica S. Borkar, Mohammed Jameel, Nahla Hasabou, Randall Brand, Zvezdana Bogojevic, Vadim Backman
753
Introduction: Accurate risk analysis is critical to tailor colorectal cancer (CRC) screening programs. The “field effect” provides a simple means of CRC risk stratification through assessment of the distal colon. However, current markers (e.g. ACF, adenomas) lack the requisite sensitivity for CRC screening. We used a powerful novel optical technology, low coherence enhanced backscattering spectroscopy (LEBS), to detect pre-dysplastic mucosal nanoscale architectural perturbations. These were remarkably sensitive to carcinogenesis in rodent CRC models (Gastro 2004, CEBP 2005, Clin Cancer Res 2006). We now assessed the clinical utility of rectal LEBS analysis using ex vivo (biopsies) and In Vivo(endoscopically compatible LEBS probe). Methods Ex vivo: 219 patients undergoing colonoscopy had 2 biopsies taken from the visually normal rectum. In Vivo: 30 patients had 5 areas each from the normal rectum assessed by a novel LEBS probe after colonoscopy. Data Analysis: 4 distinct characteristics of the LEBS spectra were quantified (slope, width etc.) and used to calculate a composite marker, the LEBS index. Results: Rectal ex vivo (open air) and In Vivo(probe) LEBS index values were markedly altered in patients harboring adenomas with the magnitude mirroring neoplastic progression (figure). Both systems showed highly statistically significant effects for large adenomas but only the probe was sensitive to diminutive lesions. For advanced adenomas, both systems had excellent performance characteristics (area under ROC curve of 0.895 and 0.93, respectively). Conclusions: LEBS index from endoscopically normal rectal mucosa measured either ex vivo or In Vivo provided accurate risk stratification through identification of the microarchectural correlates of “field effect”. In the future, it may be possible to determine the need/timing of colonoscopy at the annual physical exam using a rectal LEBS probe.
Stool DNA Screening of Colorectal Neoplasia: Improved Adenoma Detection By Novel Digital Melt Curve Assay Hongzhi Zou, Jonathan J. Harrington, Xuan Jiang, Charles L. Loprinzi, Theodore R. Levin, Douglas Rex, Dennis Ahnen, Kandice L. Knigge, Peter . Lance, Daniel J. Sargent, David A. Ahlquist To prevent colorectal cancer, screening must detect premalignant adenomas. Based on our multicenter study (Gastroenterology 2007; 132:A-3) and others from the screening setting, current approaches to both fecal blood and DNA testing miss most advanced adenomas. Higher analytical sensitivity is required to improve adenoma detection by stool DNA testing, as target markers are present in such minute amounts. We have recently developed a digital melt curve assay capable of detecting trace quantities of genetic markers. AIMS: Using archived stools from the above multicenter study (CA 89389): we sought to (1) evaluate digital melt curve (DMC) assay of DNA markers for detection of advanced adenomas and (2) compare DMC accuracy with that of occult blood testing and a commercial DNA marker assay method (EXACT Sciences). METHODS: From the multicenter study, average risk subjects had collected stools without a preservative buffer and mailed them to central processing laboratories for banking and blinded stool testing by Hemoccult, HemoccultSENSA, and DNA marker assay. All subjects underwent a colonoscopy, and tissue from advanced adenomas was archived. For the present blinded study, archival stools were selected from the 27 patients with a colorectal adenoma >1cm found to harbor mutant K-ras on tissue analyses and from the first 25 age and gender matched subjects with normal colonoscopy. Standard methods were used to extract crude DNA from fecal aliquots, and K-ras gene was enriched by sequence capture. Mutations in the K-ras gene were quantified by DMC assay based on the number of wells containing mutant gene copies in a 96-well plate and confirmed by sequencing. RESULTS: Median age with adenomas was 67 and controls 71; males/females were 12/15 and 13/14, respectively. Median adenoma size was 1.5cm (range 1-3cm). Based on a cut-off of >3 wells with mutant K-ras, the DMC assay yielded an overall sensitivity of 59% for adenomas with a specificity of 92%; sensitivity for adenomas >2cm was 80% (8/10) and for those <2cm was 47% (8/17), p=0.1. In these same stools, overall adenoma detection rates were 7% by Hemoccult, 15% by HemoccultSENSA, and
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26% by the EXACT Sciences K-ras assay (p<0.05 for each vs DMC); respective specificities were 92%, 92%, and 100%. CONCLUSIONS: Based on these comparisons, a novel and analytically-sensitive DMC assay method has the potential to detect a majority of advanced colorectal adenomas and improve yield over current stool test approaches. Further prospective studies are clearly indicated.
756 Two Dose-Equivalent, 21-Days, Subcutaneous (S.C.), Glucagon-Like Peptide 2 (GLP-2) Dosing Regimens, 1.0 Mg Continuously Versus 0.33 Mg Three Time Daily (tid), in the Treatment of Short Bowel Syndrome (SBS) Patients Palle B. Jeppesen, Ida B. Gottschalck, Jens J. Holst, Per B. Mortensen, Bolette Hartmann Background: GLP-2 may improve intestinal function in SBS patients due to beneficial effects on gastric emptying, secretion and intestinal growth. In theory, optimal timing of GLP-2 administration could be in relation to meals, attempting to restore normal meal-related gastric emptying and secretion. However, continuous GLP-2 administration may promote intestinal growth better. Methods: Two dose-equivalent, 21-days, s.c., GLP-2 dosing regimens (1.0 mg Continuously versus 0.33 mg three times daily (TID)), were compared sequentially after baseline measurements in 8 short bowel patients (5F, 3M; mean age 60±7 years; remnant small bowel 111±62 cm; 1 with 50% colon; all received home parenteral nutrition or fluids). Continuous infusion was provided by MiniMed insulin pumps; alternatively the patients injected themselves in relation to three main meals. During three 72-hours balancestudies, dietary intake, fecal and urinary excretions were analysed. The patients had free access to food and beverages, collecting exactly double portions, one for analyses. Parenteral support was kept constant. Energy (by bomb calorimetry) and wet weight absorption (by total weight) was the difference between diet intake and fecal excretion. Post-absorptive plasma citrullin, possibly reflecting enterocyte mass, was measured by HPLC. A washout period of at least 3 weeks between the two dosing regimens was required. Results: See table below. Conclusion: Both GLP-2 dosing regimens, Continuous versus TID, reduced fecal wet weight excretions and increased wet weight absorption compared to baseline measurements. The increases in urinary excretions were not significant. Both regimens tended to reduce energy intake, but since energy excretion tended to be even lower, the absolute and relative energy absorption tended to increase in relation to both treatment regimens. Significant increases in plasma citrulline suggest intestinotrophic effects in relation to GLP-2 treatment. From a clinical point of view, the effects of the two GLP-2 dosing regimens seem of the same magnitude, although type 2 errors are likely in studies of this size.
754 Flow Cytometry in Barrett Esophagus (Cybar Study): A Prospective Cohort Study Marjolein Sikkema, Marjon Kerkhof, E. W. Steyerberg, Herman van Dekken, Anneke van Vuuren, Han Geldof, Hans van der Valk, Dirk Jan Bac, Raimond Giard, Wilco Lesterhuis, Robert Heinhuis, Elly C. Klinkenberg, Gerrit A. Meijer, Frank T. Borg, Jan-Willem Arends, Jeroen J. Kolkman, Joop van Baarlen, Richard A. de Vries, Andries H. Mulder, Antonie J. Van Tilburg, Johan Offerhaus, Fiebo J. Ten Kate, Johannes G. Kusters, E. J. Kuipers, Peter D. Siersema Background and aim: The incidence of esophageal adenocarcinoma (EAC) has increased rapidly over the last decades. Barrett esophagus (BE) predisposes to EAC, with an annual risk of developing EAC of approximately 0.5%. Surveillance aims to detect neoplastic lesions at an early and curable stage. Due to sampling error and interobserver variation in dysplasia, histological evaluation is presumably of limited value in differentiating the risk for neoplastic progression. It has been suggested that biomarkers may aid in identifying high risk patients. The aim of this study was to determine the value of an abnormal DNA-content as detected by flow cytometry (FC) for the risk of neoplastic progression in BE patients. Methods: In this multicenter, prospective cohort study we included 703 BE patients with no dysplasia (ND; n=604) or low grade dysplasia (LGD; n=99) at baseline and a BE segment of 2 cm or more. Five hundred-sixty-one patients were known with BE prior to the inclusion in this study. FC analysis was performed on paraffin embedded biopsies. BE patients were stratified for different surveillance schemes based on FC result (normal =diploid DNA-content; abnormal=aneuploid DNA-content) and baseline histology. Progression towards HGD and EAC was analyzed with Kaplan-Meier curves and Cox regression to estimate hazard ratios (HR) with adjustment for potential confounding variables. Results: Eleven patients showed progression towards HGD as well as 11 towards EAC, accounting for a 2-yr cumulative risk for neoplastic progression of 6.1% (95% CI: 2.3-9.9%). Patients with baseline ND and diploidy (n=479) had a risk for progression towards HGD or EAC of 3.7% (95%CI: 1-6.4%) compared with a 0% risk for patients with aneuploidy (n=78; log rank test p=0.19). Patients with baseline LGD and diploidy (n=84) had a risk of 30% (95%CI: 21.5-39%) compared with 20% (95%CI: 3-37%) for patients with aneuploidy (n=15;log rank test p=0.50). Multivariable analysis (adjusted for age, gender and presence of dysplasia) showed no association of aneuploidy with development to HGD or EAC (HR 0.9; 95% CI:0.3-3.1). This analysis confirmed however that LGD was associated with an increased risk of developing HGD or EAC (HR 7.1; 95% CI:2.9-18). Similar results were found in repeated analyses for development of HGD or EAC alone. Conclusion: Patients whose baseline biopsies show LGD, had a 7 times increased risk of developing progression towards HGD or EAC. Aneuploidy, determined in paraffin embedded biopsies, had no evident predictive value for neoplastic progression in BE patients after two years of follow-up, although longer follow-up is needed. 755
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Endoscopic Ultrasonography Is a Valuable Tool with High Yield in Screening of Patients At High-Risk Patients for Pancreatic Cancer Jan-Werner Poley, Irma Kluijt, Dirk J. Gouma, Anja Wagner, Cora M. Aalfs, Annemieke Cats, Yung Nio, Paul Fockens, Casper H. van Eijck, E. J. Kuipers, Marco Bruno
Teduglutide, a Glucagon-Like Peptide-2 (GLP-2) Analog, Improves Fluid Balance in Short Bowel Syndrome (SBS) Patients Depending On Parenteral Support (PN) Palle B. Jeppesen, Bernard Messing, Marek Pertkiewicz, Jane Cyran, Lidia L. Demchyshyn, Ronald Kershner
Introduction: Approximately 10-15% of all pancreatic cancers (PC) are considered to be familial or hereditary in origin. Despite improvements in imaging technology and surgery, survival remains dismal in patients with PC. We investigated the use of endoscopic ultrasonography (EUS) in screening patients at high-risk of developing PC. EUS can be useful in these patients since it enables detailed visualisation of both pancreatic duct and parenchyma. Our hypothesis was that EUS might be able to detect premalignant lesions and early invasive cancers and possibly improve survival. Methods: Patients eligible for screening were 1st degree members of families with familial PC as well as mutation carriers of PC prone hereditary syndromes (CDKN2A, PRSS1, STK11, p16) or patients with Peutz-Jeghers syndrome, or mutation carriers of other PC prone hereditary syndromes and clustering (>2 case per family) of PC (BRCA1/2, APC, p53, mismatch repair genes). All patients were asymptomatic and had not undergone EUS before. Results: 43 patients (M/F 18/25), age 32 - 75 years, median 51 years, underwent their first screening with EUS. No complications occurred. Genetic background was diverse: 13 patients (8 were known p16 mutation carriers) were from families with FAMMM (familial atypical multiple mole melanoma), 21 patients were from families with familial PC, 3 patients were diagnosed with hereditary pancreatitis (proven mutations in PRSS1 gene), 2 Peutz-Jeghers patients, 3 BRCA1 and 2 BRCA2 mutation carriers with familial clustering of PC and 1 patient with a p53 mutation. In three patients (2 proven FAMMM syndrome, 1 with a BRCA2 mutation) asymptomatic mass lesions (12, 27 and 50 mm) were found in the body and tail of the pancreas. The smallest lesion was not visualised on subsequent CT and MRI. All underwent surgery and were found to have moderately differentiated adenocarcinomas. All lesions were competely removed, however the patients with the larger lesions were found to have N1 disease (5/11 and 1/9 nodes positive). Sidebranch intraductal papillary mucinous neoplasias (IPMN) were found in 7 patients: 3 with FAMMM syndrome, 3 in patients with familial PC (1 multifocal) and 1 in a BCRA1 mutation carrier. Conclusion: Screening patients at high-risk for PC with EUS is feasible and safe. The incidence of clinically relevant findings is high with 7% asymptomatic cancers and 16% premalignant lesions in this series. Whether screening improves survival remains to be investigated, as is the optimal interval for screening. Sidebranch IPMN is frequently encountered in these patients and may serve as a precancerous marker lesion for early intervention to improve survival.
AGA Abstracts
In a phase 2 study, where PN and oral intake was kept constant, teduglutide decreased fecal wet weight (WW) excretion and increased WW absorption in SBS patients by ~700 g/day, thus increasing urinary excretion by ~600 g/day. The effects on energy absorption were minor. A decrease in fecal WW excretion may also translate into reductions in oral intake, increases in urine excretion and improvements in fluid balance/hydration; all beneficial effects in SBS. Thus, focusing on just one endpoint, reduction in PN, not considering the broader spectrum, may lead to an underestimation of the effects of new drugs. Methods: The primary endpoint, a relative reduction of at least 20% in PN, in a 24-week multicenter, randomized, double blind, placebo-controlled study of subcutaneous teduglutide 0.05 or 0.1 mg/kg/d in 83 PN-dependent SBS patients is presented elsewhere. The absolute effects of teduglutide on volumes of PN, oral fluid intake, and urine excretion are presented in the Table. These values were obtained by adjusting the raw data, given as PN per week and oral intake/urine output per 48 hours, to 24 hour equivalent volumes. Results: Teduglutide numerically reduces the need for PN in both dosing groups (~150-200 mL/d compared to placebo). The 0.05 mg/kg/day dose significantly increases urinary excretion (~300 mL/d), illustrating that weaning from PN could have been even more aggressive. In spite of the reduced oral intake (~300 mL/d) in patients given the 0.1 mg/kg/day dose, they maintained the same urine excretion. Conclusion: Thus, the study design and the PN weaning algorithm may lead to an underestimation of the true effect of teduglutide, when only considering reduction in PN as an isolated endpoint. Thus, the average effect of Teduglutide on intestinal wet weight absorption is likely to be >500 mL/d confirming findings from the phase 2 study.
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Identification of Inherited Predisposition to Colonic Neoplasia Through Partial Wave Spectroscopic Analysis of the Microscopically Normal Colonic Epithelium Hemant K. Roy, Hariharan Subramanian, Prabhakar Pradhan, Henry T. Lynch, David Weinberg, Zvezdana Bogojevic, Nahla Hasabou, Jennifer Koetsier, Ramesh K. Wali, Stephen J. Lanspa, Michael J. Goldberg, Dhananjay Kunte, Vadim Backman While familial risk comprises ~20-30% of all colorectal cancers (CRC), in most cases the genetic etiology is not readily identifiable. Thus, counselling CRC-prone families members is not based on individized risk assessment (e.g. one size fits all approach). Our group has developed novel light scattering technologies such as partial wave spectroscopy (PWS)to quantitate nanoscale architecture. We have noted that pre-dysplastic mucosal optical signatures provided a highly sensitive means of detecting CRC risk in experimental models(Gastro 2004, CEBP 2005, Clin Cancer Res 2006). Moreover, the PWS parameter, disorder strength (Ld), was markedly elevated in the endoscopically normal rectal mucosa of patients harboring adenomas (i.e. “field effect”). We now explore whether colonic Ld could detect a genetic predisposition to CRC. Methods: Animal studies: MIN (murine model of FAP with APC gene mutation) or age-matched wildtype mice were euthanized and had intestinal brushings taken of neoplasia-free areas Human Studies 35 patients with HNPCC mutation-confirmed (hMLH-1&hMSH-2),adenoma-free or controls (age-matched but no personal/family history) had rectal brushings taken during colonoscopy. PWS analysis: Ld and standard deviation of Ld (SDLd) were calculated by investigator blinded to clinical findings Results Ld was markedly elevated in the normal mucosa of germline carriers when compared to controls (figure). This, coupled with SDLd, allowed clear descrimination between cases and controls(both murine and human model. Conclusions: Ld and SDLd from the visually normal mucosa identified APC and hMLH1/hMSH2 mutations prior to phenotype development. Thus, probing nanoscale perturbations from readily accessible mucosa (e.g. rectum) may provide a modality for determing both the carriage of these syndromic mutations and possibly allow detection of the more common lower penetrant CRC risk genes.
752 Fluorodeoxyglucose-Positron Emission Tomography Scan (FDG-PET Scan) in the Diagnosis of Colorectal Cancer Recurrence Céline Deleau, Bruno Buecher, Caroline Rousseau, Françoise Kraeber-Bodéré, Stanislas Bruley des Varannes, Jean Paul Galmiche, Tamara Matysiak-Budnik Introduction: Early detection is an essential prognostic factor in colorectal cancer (CRC) recurrence. It has been suggested that FDG-PET Scan is more sensitive than computed tomography (CT) in the detection of early peritoneal carcinomatosis, lymph node metastases or neoplastic components within residual mass. Aims and methods: Our aim was to evaluate diagnostic performances of FDG-PET Scan in the detection of CRC recurrence and to determine the impact of FDG-PET Scan on clinical management of the patients. All CT and FDG-PET Scans performed in a single department between 2002 and 2006 for suspicion of CRC recurrence were analyzed retrospectively. All detected lesions were characterized according to their number, size, and anatomical localization. The lesions stable on at least two consecutives examinations were considered negative. The gold standard was histology or radiological follow-up according to the RECIST criteria of progression. Diagnostic sensitivity was calculated globally and with respect to the localization and the results of carcinoembryonic antigen (CEA) dosage. Diagnostic and therapeutic impact of FDG-PET Scan was evaluated by comparing pre- and post-FDG-PET Scan strategies. Results: One hundred and seven FDG-PET Scans, performed in 92 patients, were analyzed. One hundred eighty lesions (57 hepatic and 123 extrahepatic) were identified. Serum CEA dosage was obtained in 79/ 106 cases and was normal in 61% of patients and elevated in 39% of patients. Out of 186 lesions identified by FDG-PET Scan, 172 were true positive and 14 false positive. Out of 119 lesions identified by CT, 98 were true positive and 21 false positive. Ten patients were free of relapse. The global sensitivity for the detection of neoplastic lesions was of 95.6% for FDG-PET Scan and 55.1% for CT. In patients with elevated CEA, this value was of 96.8% for FDG-PET Scan and 49.2% for CT. Sensitivity of FDG-PET Scan for the detection of extrahepatic abdominal metastases was 100%. As compared to CT, FDG-PET Scan had a diagnostic impact in 58% of cases and led to modification of therapy in 33% of patients (avoidance of surgery in 8 patients, earlier decision of curative treatment in 6 patients, and earlier instauration of palliative chemotherapy in 7 cases). Conclusions: FDG-PET Scan is more sensitive than CT for diagnosis of CRC recurrence, in particular in patients with elevated CEA and in case of extra-hepatic abdominal metastases. FDG-PET Scan results can modify the management in about one third of the patients and thus should be proposed as a routine examination in patients with suspicion of CRC recurrence.
751 Prediction of Colonic Neoplasia Through Spectral Marker Analysis from the Endoscopically Normal Rectum: An Ex Vivo and In Vivo Study Hemant K. Roy, Vladimir Turzhitsky, Andrew Gomes, Michael J. Goldberg, Jeremy D. Rogers, Young L. Kim, Tat-Kin Tsang, Dhiren Shah, Monica S. Borkar, Mohammed Jameel, Nahla Hasabou, Randall Brand, Zvezdana Bogojevic, Vadim Backman
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Introduction: Accurate risk analysis is critical to tailor colorectal cancer (CRC) screening programs. The “field effect” provides a simple means of CRC risk stratification through assessment of the distal colon. However, current markers (e.g. ACF, adenomas) lack the requisite sensitivity for CRC screening. We used a powerful novel optical technology, low coherence enhanced backscattering spectroscopy (LEBS), to detect pre-dysplastic mucosal nanoscale architectural perturbations. These were remarkably sensitive to carcinogenesis in rodent CRC models (Gastro 2004, CEBP 2005, Clin Cancer Res 2006). We now assessed the clinical utility of rectal LEBS analysis using ex vivo (biopsies) and In Vivo(endoscopically compatible LEBS probe). Methods Ex vivo: 219 patients undergoing colonoscopy had 2 biopsies taken from the visually normal rectum. In Vivo: 30 patients had 5 areas each from the normal rectum assessed by a novel LEBS probe after colonoscopy. Data Analysis: 4 distinct characteristics of the LEBS spectra were quantified (slope, width etc.) and used to calculate a composite marker, the LEBS index. Results: Rectal ex vivo (open air) and In Vivo(probe) LEBS index values were markedly altered in patients harboring adenomas with the magnitude mirroring neoplastic progression (figure). Both systems showed highly statistically significant effects for large adenomas but only the probe was sensitive to diminutive lesions. For advanced adenomas, both systems had excellent performance characteristics (area under ROC curve of 0.895 and 0.93, respectively). Conclusions: LEBS index from endoscopically normal rectal mucosa measured either ex vivo or In Vivo provided accurate risk stratification through identification of the microarchectural correlates of “field effect”. In the future, it may be possible to determine the need/timing of colonoscopy at the annual physical exam using a rectal LEBS probe.
Stool DNA Screening of Colorectal Neoplasia: Improved Adenoma Detection By Novel Digital Melt Curve Assay Hongzhi Zou, Jonathan J. Harrington, Xuan Jiang, Charles L. Loprinzi, Theodore R. Levin, Douglas Rex, Dennis Ahnen, Kandice L. Knigge, Peter . Lance, Daniel J. Sargent, David A. Ahlquist To prevent colorectal cancer, screening must detect premalignant adenomas. Based on our multicenter study (Gastroenterology 2007; 132:A-3) and others from the screening setting, current approaches to both fecal blood and DNA testing miss most advanced adenomas. Higher analytical sensitivity is required to improve adenoma detection by stool DNA testing, as target markers are present in such minute amounts. We have recently developed a digital melt curve assay capable of detecting trace quantities of genetic markers. AIMS: Using archived stools from the above multicenter study (CA 89389): we sought to (1) evaluate digital melt curve (DMC) assay of DNA markers for detection of advanced adenomas and (2) compare DMC accuracy with that of occult blood testing and a commercial DNA marker assay method (EXACT Sciences). METHODS: From the multicenter study, average risk subjects had collected stools without a preservative buffer and mailed them to central processing laboratories for banking and blinded stool testing by Hemoccult, HemoccultSENSA, and DNA marker assay. All subjects underwent a colonoscopy, and tissue from advanced adenomas was archived. For the present blinded study, archival stools were selected from the 27 patients with a colorectal adenoma >1cm found to harbor mutant K-ras on tissue analyses and from the first 25 age and gender matched subjects with normal colonoscopy. Standard methods were used to extract crude DNA from fecal aliquots, and K-ras gene was enriched by sequence capture. Mutations in the K-ras gene were quantified by DMC assay based on the number of wells containing mutant gene copies in a 96-well plate and confirmed by sequencing. RESULTS: Median age with adenomas was 67 and controls 71; males/females were 12/15 and 13/14, respectively. Median adenoma size was 1.5cm (range 1-3cm). Based on a cut-off of >3 wells with mutant K-ras, the DMC assay yielded an overall sensitivity of 59% for adenomas with a specificity of 92%; sensitivity for adenomas >2cm was 80% (8/10) and for those <2cm was 47% (8/17), p=0.1. In these same stools, overall adenoma detection rates were 7% by Hemoccult, 15% by HemoccultSENSA, and
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26% by the EXACT Sciences K-ras assay (p<0.05 for each vs DMC); respective specificities were 92%, 92%, and 100%. CONCLUSIONS: Based on these comparisons, a novel and analytically-sensitive DMC assay method has the potential to detect a majority of advanced colorectal adenomas and improve yield over current stool test approaches. Further prospective studies are clearly indicated.
756 Two Dose-Equivalent, 21-Days, Subcutaneous (S.C.), Glucagon-Like Peptide 2 (GLP-2) Dosing Regimens, 1.0 Mg Continuously Versus 0.33 Mg Three Time Daily (tid), in the Treatment of Short Bowel Syndrome (SBS) Patients Palle B. Jeppesen, Ida B. Gottschalck, Jens J. Holst, Per B. Mortensen, Bolette Hartmann Background: GLP-2 may improve intestinal function in SBS patients due to beneficial effects on gastric emptying, secretion and intestinal growth. In theory, optimal timing of GLP-2 administration could be in relation to meals, attempting to restore normal meal-related gastric emptying and secretion. However, continuous GLP-2 administration may promote intestinal growth better. Methods: Two dose-equivalent, 21-days, s.c., GLP-2 dosing regimens (1.0 mg Continuously versus 0.33 mg three times daily (TID)), were compared sequentially after baseline measurements in 8 short bowel patients (5F, 3M; mean age 60±7 years; remnant small bowel 111±62 cm; 1 with 50% colon; all received home parenteral nutrition or fluids). Continuous infusion was provided by MiniMed insulin pumps; alternatively the patients injected themselves in relation to three main meals. During three 72-hours balancestudies, dietary intake, fecal and urinary excretions were analysed. The patients had free access to food and beverages, collecting exactly double portions, one for analyses. Parenteral support was kept constant. Energy (by bomb calorimetry) and wet weight absorption (by total weight) was the difference between diet intake and fecal excretion. Post-absorptive plasma citrullin, possibly reflecting enterocyte mass, was measured by HPLC. A washout period of at least 3 weeks between the two dosing regimens was required. Results: See table below. Conclusion: Both GLP-2 dosing regimens, Continuous versus TID, reduced fecal wet weight excretions and increased wet weight absorption compared to baseline measurements. The increases in urinary excretions were not significant. Both regimens tended to reduce energy intake, but since energy excretion tended to be even lower, the absolute and relative energy absorption tended to increase in relation to both treatment regimens. Significant increases in plasma citrulline suggest intestinotrophic effects in relation to GLP-2 treatment. From a clinical point of view, the effects of the two GLP-2 dosing regimens seem of the same magnitude, although type 2 errors are likely in studies of this size.
754 Flow Cytometry in Barrett Esophagus (Cybar Study): A Prospective Cohort Study Marjolein Sikkema, Marjon Kerkhof, E. W. Steyerberg, Herman van Dekken, Anneke van Vuuren, Han Geldof, Hans van der Valk, Dirk Jan Bac, Raimond Giard, Wilco Lesterhuis, Robert Heinhuis, Elly C. Klinkenberg, Gerrit A. Meijer, Frank T. Borg, Jan-Willem Arends, Jeroen J. Kolkman, Joop van Baarlen, Richard A. de Vries, Andries H. Mulder, Antonie J. Van Tilburg, Johan Offerhaus, Fiebo J. Ten Kate, Johannes G. Kusters, E. J. Kuipers, Peter D. Siersema Background and aim: The incidence of esophageal adenocarcinoma (EAC) has increased rapidly over the last decades. Barrett esophagus (BE) predisposes to EAC, with an annual risk of developing EAC of approximately 0.5%. Surveillance aims to detect neoplastic lesions at an early and curable stage. Due to sampling error and interobserver variation in dysplasia, histological evaluation is presumably of limited value in differentiating the risk for neoplastic progression. It has been suggested that biomarkers may aid in identifying high risk patients. The aim of this study was to determine the value of an abnormal DNA-content as detected by flow cytometry (FC) for the risk of neoplastic progression in BE patients. Methods: In this multicenter, prospective cohort study we included 703 BE patients with no dysplasia (ND; n=604) or low grade dysplasia (LGD; n=99) at baseline and a BE segment of 2 cm or more. Five hundred-sixty-one patients were known with BE prior to the inclusion in this study. FC analysis was performed on paraffin embedded biopsies. BE patients were stratified for different surveillance schemes based on FC result (normal =diploid DNA-content; abnormal=aneuploid DNA-content) and baseline histology. Progression towards HGD and EAC was analyzed with Kaplan-Meier curves and Cox regression to estimate hazard ratios (HR) with adjustment for potential confounding variables. Results: Eleven patients showed progression towards HGD as well as 11 towards EAC, accounting for a 2-yr cumulative risk for neoplastic progression of 6.1% (95% CI: 2.3-9.9%). Patients with baseline ND and diploidy (n=479) had a risk for progression towards HGD or EAC of 3.7% (95%CI: 1-6.4%) compared with a 0% risk for patients with aneuploidy (n=78; log rank test p=0.19). Patients with baseline LGD and diploidy (n=84) had a risk of 30% (95%CI: 21.5-39%) compared with 20% (95%CI: 3-37%) for patients with aneuploidy (n=15;log rank test p=0.50). Multivariable analysis (adjusted for age, gender and presence of dysplasia) showed no association of aneuploidy with development to HGD or EAC (HR 0.9; 95% CI:0.3-3.1). This analysis confirmed however that LGD was associated with an increased risk of developing HGD or EAC (HR 7.1; 95% CI:2.9-18). Similar results were found in repeated analyses for development of HGD or EAC alone. Conclusion: Patients whose baseline biopsies show LGD, had a 7 times increased risk of developing progression towards HGD or EAC. Aneuploidy, determined in paraffin embedded biopsies, had no evident predictive value for neoplastic progression in BE patients after two years of follow-up, although longer follow-up is needed. 755
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Endoscopic Ultrasonography Is a Valuable Tool with High Yield in Screening of Patients At High-Risk Patients for Pancreatic Cancer Jan-Werner Poley, Irma Kluijt, Dirk J. Gouma, Anja Wagner, Cora M. Aalfs, Annemieke Cats, Yung Nio, Paul Fockens, Casper H. van Eijck, E. J. Kuipers, Marco Bruno
Teduglutide, a Glucagon-Like Peptide-2 (GLP-2) Analog, Improves Fluid Balance in Short Bowel Syndrome (SBS) Patients Depending On Parenteral Support (PN) Palle B. Jeppesen, Bernard Messing, Marek Pertkiewicz, Jane Cyran, Lidia L. Demchyshyn, Ronald Kershner
Introduction: Approximately 10-15% of all pancreatic cancers (PC) are considered to be familial or hereditary in origin. Despite improvements in imaging technology and surgery, survival remains dismal in patients with PC. We investigated the use of endoscopic ultrasonography (EUS) in screening patients at high-risk of developing PC. EUS can be useful in these patients since it enables detailed visualisation of both pancreatic duct and parenchyma. Our hypothesis was that EUS might be able to detect premalignant lesions and early invasive cancers and possibly improve survival. Methods: Patients eligible for screening were 1st degree members of families with familial PC as well as mutation carriers of PC prone hereditary syndromes (CDKN2A, PRSS1, STK11, p16) or patients with Peutz-Jeghers syndrome, or mutation carriers of other PC prone hereditary syndromes and clustering (>2 case per family) of PC (BRCA1/2, APC, p53, mismatch repair genes). All patients were asymptomatic and had not undergone EUS before. Results: 43 patients (M/F 18/25), age 32 - 75 years, median 51 years, underwent their first screening with EUS. No complications occurred. Genetic background was diverse: 13 patients (8 were known p16 mutation carriers) were from families with FAMMM (familial atypical multiple mole melanoma), 21 patients were from families with familial PC, 3 patients were diagnosed with hereditary pancreatitis (proven mutations in PRSS1 gene), 2 Peutz-Jeghers patients, 3 BRCA1 and 2 BRCA2 mutation carriers with familial clustering of PC and 1 patient with a p53 mutation. In three patients (2 proven FAMMM syndrome, 1 with a BRCA2 mutation) asymptomatic mass lesions (12, 27 and 50 mm) were found in the body and tail of the pancreas. The smallest lesion was not visualised on subsequent CT and MRI. All underwent surgery and were found to have moderately differentiated adenocarcinomas. All lesions were competely removed, however the patients with the larger lesions were found to have N1 disease (5/11 and 1/9 nodes positive). Sidebranch intraductal papillary mucinous neoplasias (IPMN) were found in 7 patients: 3 with FAMMM syndrome, 3 in patients with familial PC (1 multifocal) and 1 in a BCRA1 mutation carrier. Conclusion: Screening patients at high-risk for PC with EUS is feasible and safe. The incidence of clinically relevant findings is high with 7% asymptomatic cancers and 16% premalignant lesions in this series. Whether screening improves survival remains to be investigated, as is the optimal interval for screening. Sidebranch IPMN is frequently encountered in these patients and may serve as a precancerous marker lesion for early intervention to improve survival.
AGA Abstracts
In a phase 2 study, where PN and oral intake was kept constant, teduglutide decreased fecal wet weight (WW) excretion and increased WW absorption in SBS patients by ~700 g/day, thus increasing urinary excretion by ~600 g/day. The effects on energy absorption were minor. A decrease in fecal WW excretion may also translate into reductions in oral intake, increases in urine excretion and improvements in fluid balance/hydration; all beneficial effects in SBS. Thus, focusing on just one endpoint, reduction in PN, not considering the broader spectrum, may lead to an underestimation of the effects of new drugs. Methods: The primary endpoint, a relative reduction of at least 20% in PN, in a 24-week multicenter, randomized, double blind, placebo-controlled study of subcutaneous teduglutide 0.05 or 0.1 mg/kg/d in 83 PN-dependent SBS patients is presented elsewhere. The absolute effects of teduglutide on volumes of PN, oral fluid intake, and urine excretion are presented in the Table. These values were obtained by adjusting the raw data, given as PN per week and oral intake/urine output per 48 hours, to 24 hour equivalent volumes. Results: Teduglutide numerically reduces the need for PN in both dosing groups (~150-200 mL/d compared to placebo). The 0.05 mg/kg/day dose significantly increases urinary excretion (~300 mL/d), illustrating that weaning from PN could have been even more aggressive. In spite of the reduced oral intake (~300 mL/d) in patients given the 0.1 mg/kg/day dose, they maintained the same urine excretion. Conclusion: Thus, the study design and the PN weaning algorithm may lead to an underestimation of the true effect of teduglutide, when only considering reduction in PN as an isolated endpoint. Thus, the average effect of Teduglutide on intestinal wet weight absorption is likely to be >500 mL/d confirming findings from the phase 2 study.
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