Advanced Adenoma Patients Research Articles

Role of baseline adenoma characteristics for adenoma recurrencein patients with high-risk adenoma

Background/aim: The present observational study aimed to determine the predictive value of 3-year recurrence adenoma characteristics at baseline conventional colonoscopy in patients with high-risk adenoma.Materials and methods: A total of 47 patients with high-risk adenoma at baseline colonoscopy were followed up and underwent a surveillance colonoscopy at 3 years. Correlations between adenoma recurrence and baseline adenoma characteristics (size, number, histological features, and location) were analyzed.Results: Among 135 patients with high-risk adenoma, 47 patients (35%) who underwent surveillance colonoscopy at 3 years following baseline colonoscopy were included in the study. In these 47 patients, at least one new adenoma was detected in 19 (40.4%) patients, and new advanced adenomas were detected in 5 (10.6%) patients during the surveillance colonoscopy. No significant difference was found in patients who had adenoma recurrence versus those who did not in terms of size of adenomas (P = 0.143), number of adenomas (P = 0.562), histological properties of adenomas (P = 0.658), or locations of adenomas (P = 0.567).Conclusion: Baseline adenoma characteristics were not associated with the recurrence of adenomas or advanced adenomas in patients with high-risk adenoma.

Evaluation of a 5-Marker Blood Test for Colorectal Cancer Early Detection in a Colorectal Cancer Screening Setting.

In initial studies that included colorectal cancer patients undergoing diagnostic colonoscopy, we had identified a serum marker combination able to detect colorectal cancer with similar diagnostic performance as fecal immunochemical test (FIT). In this study, we aimed to validate the results in participants of a large colorectal cancer screening study conducted in the average-risk, asymptomatic screening population. We tested serum samples from 1,200 controls, 420 advanced adenoma patients, 4 carcinoma in situ patients, and 36 colorectal cancer patients with a 5-marker blood test [carcinoembryonic antigen (CEA)+anti-p53+osteopontin+seprase+ferritin]. The diagnostic performance of individual markers and marker combinations was assessed and compared with stool test results. AUCs for the detection of colorectal cancer and advanced adenomas with the 5-marker blood test were 0.78 [95% confidence interval (CI), 0.68-0.87] and 0.56 (95% CI, 0.53-0.59), respectively, which now is comparable with guaiac-based fecal occult blood test (gFOBT) but inferior to FIT. With cutoffs yielding specificities of 80%, 90%, and 95%, the sensitivities for the detection of colorectal cancer were 64%, 50%, and 42%, and early-stage cancers were detected as well as late-stage cancers. For osteopontin, seprase, and ferritin, the diagnostic performance in the screening setting was reduced compared with previous studies in diagnostic settings while CEA and anti-p53 showed similar diagnostic performance in both settings. Performance of the 5-marker blood test under screening conditions is inferior to FIT even though it is still comparable with the performance of gFOBT. CEA and anti-p53 could contribute to the development of a multiple marker blood-based test for early detection of colorectal cancer.

Prevalence of Advanced Colorectal Adenomas in Patients Undergoing Screening Colonoscopy in a Safety-net Hospital

Introduction: Advanced colorectal adenomas are important precancerous lesions and include adenomas>9mm in size, tubulovillous histology, and high grade dysplasia. The aim of this study is to measure the prevalence of adenomas and advanced adenomas in patients undergoing screening colonoscopy, and to compare the prevalence in African Americans and other racial groups. Methods: We performed a retrospective analysis of all asymptomatic patients who underwent screening colonoscopy between July 1st 2009 and June 30th 2014. Patients with history of polyps, positive FOBT, diagnostic, or incomplete/inadequate colonoscopies were excluded. Data about patients' age, race, gender, quality of colon preparation, fellow participation (none, first, second, and third year), adenoma detection, size, location and histology were analyzed. Logistic regression was used to calculate the crude and adjusted odds ratios for the association of colonic findings with African Americans compared to other racial groups. Results: A total of 7171 screening colonoscopies were performed during the study period. 6448 patients (90%) had an adequate and complete examination, 632 patients (8.8%) had an inadequate/poor colon preparation, and 48 patients (0.7%) had failed cecal intubation. Among patients with adequate and complete examination, 2326 (36%) were men and 4122 (64%) women. Mean age was 58 years. The majority of patients were African Americans (n=5691, 88.4%), followed by white (n=334, 5.2%), Hispanic (n=213, 3.3%) and Asian (n=105, 1.6%). The overall prevalence of adenomas was 32.3%, and that of advanced adenomas was 8.3%. Overall, African Americans had similar rates of advanced adenomas compared to other racial groups (adjusted OR 1.15, 95% CI 0.9-1.5). There was a higher rate of high grade dysplasia/ cancer in African Americans compared with other racial groups (1.4% Vs. 0.5%, adjusted OR 2.9, 95% CI 1.1-8). Rates of nonadvanced adenomas, adenomas>9mm, and adenomas with tubulovillous histology were similar among both groups (table 1). The distribution of adenomas in the proximal and distal colon was similar in both groups. Conclusion: The overall prevalence of advanced adenomas was similar between African Americans and other racial groups. However, the prevalence of adenomas with dysplasia/cancer was significantly higher in African Americans. This supports the need for special efforts to improve colorectal cancer screening participation rates in African Americans.Table 1: Prevalence of advanced adenomas among African Americans and other racial groups

Inhibitory effect of metformin therapy on the incidence of colorectal advanced adenomas in patients with diabetes.

Background/AimsMetformin use has been associated with decreased colorectal cancer risk and mortality among diabetic patients. Recent research suggests that metformin use may decrease the incidence of colorectal adenomas in diabetic patients with previous colorectal cancer. This study aimed to assess the clinical effect of metformin use on the development of colorectal adenomas in diabetic patients without previous colorectal cancer.MethodsAmong 604 consecutive diabetic patients who underwent colonoscopic surveillance after initial colonoscopy between January 2002 and June 2012, 240 patients without previous colorectal cancer were enrolled in this study and were divided in two groups: 151 patients receiving metformin and 89 patients not receiving metformin. Patient demographics and clinical characteristics as well as the colorectal adenoma incidence rate were retrospectively analyzed.ResultsThe incidence rate of total colorectal adenomas was not different according to metformin use (P=0.349). However, the advanced adenoma incidence rate was significantly lower in the metformin group compared with the non-metformin group (relative risk [RR], 0.09; P=0.011). Metformin use was independently associated with a decreased incidence of advanced colorectal adenomas after adjustment for clinically relevant factors (RR, 0.072; P=0.016). In addition, the cumulative development rate of advanced adenomas during follow-up was significantly lower in the metformin group compared with the non-metformin group (P=0.007).ConclusionsMetformin use in diabetic patients without previous colorectal cancer is associated with a lower risk of advanced colorectal adenomas.

Risks for Advanced Adenomas in Patients with a Positive Family History of Sporadic Colorectal Cancer Have a Bimodal Age Distribution

Risks for Advanced Adenomas in Patients with a Positive Family History of Sporadic Colorectal Cancer Have a Bimodal Age Distribution

Serum miR-21 as a Diagnostic and Prognostic Biomarker in Colorectal Cancer

The oncogenic microRNAs (miRNAs) miR-21 and miR-31 negatively regulate tumor-suppressor genes. Their potential as serum biomarkers has not been determined in human colorectal cancer (CRC). To determine whether miR-21 and miR-31 are secretory miRNAs, we screened expression in medium from 2 CRC cell lines, which was followed by serum analysis from 12 CRC patients and 12 control subjects. We validated expression of candidate miRNAs in serum samples from an independent cohort of 186 CRC patients, 60 postoperative patients, 43 advanced adenoma patients, and 53 control subjects. We analyzed miR-21 expression in 166 matched primary CRC tissues to determine whether serum miRNAs reflect expression in CRC. Patient survival analyses were performed by Kaplan-Meier analyses and Cox regression models. All statistical tests were two-sided. Although miR-21 was secreted from CRC cell lines and upregulated in serum of CRC patients, no statistically significant differences were observed in serum miR-31 expression between CRC patients and control subjects. In the validation cohort, miR-21 levels were statistically significantly elevated in preoperative serum from patients with adenomas (P < .001) and CRCs (P < .001). Importantly, miR-21 expression dropped in postoperative serum from patients who underwent curative surgery (P < .001). Serum miR-21 levels robustly distinguished adenoma (area under the curve [AUC] = 0.813; 95% confidence interval [CI] = 0.691 to 0.910) and CRC (AUC = 0.919; 95% CI = 0.867 to 0.958) patients from control subjects. High miR-21 expression in serum and tissue was statistically significantly associated with tumor size, distant metastasis, and poor survival. Moreover, serum miR-21 was an independent prognostic marker for CRC (hazard ratio = 4.12; 95% CI = 1.10 to 15.4; P = .03). Serum miR-21 is a promising biomarker for the early detection and prognosis of CRC.

Identification and Evaluation of Plasma MicroRNAs for Early Detection of Colorectal Cancer

BackgroundColorectal cancer (CRC) is one of the most commonly diagnosed cancers. Circulating microRNAs (miRNAs) have been suggested as potentially promising markers for early detection of CRC. We aimed to identify and evaluate a panel of miRNAs that might be suitable for CRC early detection.MethodsMiRNAs were profiled by TaqMan MicroRNA Array and screened for differential expression in 5 pools of plasma samples of CRC patients (N = 50) and 5 pools of neoplasm-free controls (N = 50). Additional miRNAs were selected from a literature review. Identified candidates were evaluated in independent validation samples with respect to discrimination of CRC patients (N = 80) or advanced adenoma patients (N = 50) and neoplasm-free controls (N = 194). Diagnostic performance of the panel of miRNAs was assessed by multiple logistic regression, using bootstrap analysis to correct for over-optimism.ResultsFive miRNAs identified to be differentially expressed from TaqMan MicroRNA Array (miR-29a, -106b, -133a, -342-3p, -532-3p), and seven miRNAs reported to be differentially expressed in the literature (miR-18a, -20a, -21, -92a, -143, -145, -181b) were selected for validation. Nine of the twelve miRNAs (miR-18a, -20a, -21, -29a, -92a, -106b, -133a, -143, -145) were found to be differentially expressed in CRC patients and controls in the validation samples. The optimism-corrected area under the curve was 0.745 (95% confidence interval: 0.708–0.846). None of the selected miRNAs showed significant differential expression between advanced adenoma patients and neoplasm-free controls.ConclusionThe identified panel of miRNAs could be of potential use in the development of a multi-marker blood based test for early detection of CRC. Impact: The study underscores the high potential of plasma miRNAs for the improvement of current offers of non-invasive CRC screening.

Serum miR-21 and miR-92a as biomarkers in the diagnosis and prognosis of colorectal cancer

Previous studies from our laboratory identified a number of miRNAs that were aberrantly expressed in colorectal cancer (CRC) tissue. However, their diagnostic and prognostic value in serum has not been fully evaluated. In the present study, we measured the levels of five miRNAs (miR-21, miR-31, miR-92a, miR-18a, and miR-106a) in serum samples from 200 CRC patients, 50 advanced adenoma patients, and 80 healthy controls by real-time quantitative polymerase chain reaction (RT-PCR). In our study, the levels of miR-21 and miR-92a in patients with CRC and advanced adenoma were significantly higher than those in healthy controls (all P < 0.05). MiR-21 yielded an area under the receiver-operating characteristics (ROC) curve (AUC) of 0.802 and miR-92a yielded an AUC of 0.786 in discriminating CRCs from the controls. Additionally, miR-21 and miR-92a yielded an AUC of 0.709 and 0.701, respectively, in discriminating advanced adenomas from the controls. Combined ROC analyses using both miRNAs, revealed an elevated AUC of 0.847 in discriminating CRCs, and an AUC of 0.722 in discriminating advanced adenomas from the controls. In the multivariate Cox proportional hazards analysis, high miR-92a expression in CRC was independently associated with poor survival (P = 0.03; hazard ratio 4.36; 95 % confidence interval = 1.64-11.57). No significant difference was observed in the levels of miR-18a, miR-31, and miR-106a among CRC, advanced adenoma, and control samples. In summary, our data indicate that miR-21 and miR-92a serum levels have potential value for early detection of CRC. Furthermore, miR-92a has prognostic value in CRC patients.

High-Resolution Melting Assay (HRMA) is a Simple and Sensitive Stool-Based DNA Test for the Detection of Mutations in Colorectal Neoplasms

Stool-based DNA testing for colorectal cancer is becoming a favored alternative to existing DNA screening tests. However, current methods of analysis often become more complicated and costly with increased sensitivity. The high-resolution melting assay (HRMA) is a simple and rapid mutation scanning method with low cost and superb accuracy. In this study, we verified the accuracy of HRMA for screening KRAS/TP53 mutations in stool-isolated DNA from patients with colorectal cancer. Comparing to direct DNA sequencing, the accuracy of HRMA was verified by detecting KRAS/TP53 mutations in 2 independent stages. In study stage I, both tissue and stool samples from colorectal neoplasm patients were analyzed. In study stage II, stool samples from patients with colorectal neoplasms, and normal controls in clinical screening settings were examined. In study stage I, the HRMA identified 14 of 17 target mutations (82.4%) in stools from cancer patients, and 4 of 5 (80.0%) target mutations in stools from advanced adenoma patients. The mutation detection rate in fecal samples (45.0%; 18/40) and referred tissue samples (55.0%; 22/40) was highly consistent (κ = 0.79). The HRMA detected 1% mutant DNA in a background of wild type DNA. In study stage II, the HRMA assay detected 58.8% (20/34) mutations in tumor samples, 41.5% (17/41) in advanced adenomas samples, and 3.33% (2/60) in age-matched normal control samples. The results from HRMA and DNA sequencing revealed 100% sensitivity and specificity in both tissue and stool samples. HRMA is a simple, reliable, and sensitive method for detecting DNA mutations in the stool samples from patients with colorectal neoplasms.

Follow-up of patients undergoing both semiquantitated immunochemical fecal occult blood and colonoscopy examinations

The semiquantitated immunochemical fecal occult blood test (I-FOBT) used for colorectal cancer (CRC) screening has had its long-term performance characteristics determined by clinical follow-up or sometimes by colonoscopy as the 'gold standard'. We reanalyzed a file of total colonoscopy patients who also prepared three I-FOBTs, processed by the OC-MICRO instrument, using at least 50 ng Hb/ml buffer threshold to determine a positive test. The performance of both tests was evaluated by the National Cancer Registry follow-up to identify new CRCs and by determining the effects of the number of tests prepared and their thresholds for analysis, sex, and age on results. A total of 1630 patients, mean age 62.7 years, SD 11.9, 50.1% men, having undergone both tests were followed up for a mean of 51.5 months, SD 13.4; 25 CRC patients were registered. At 36 months, I-FOBT sensitivity for CRC was 95.8% (95% confidence interval 87.8, 104), as was initial colonoscopy; within 48 months, it was 92% (95% confidence interval 81.4, 103) and 96%, respectively. I-FOBT identified 70 of the 122 (57.2%) colonoscopy-detected advanced adenoma patients. CRC and advanced adenomatous polyps were more common in men (P<0.01), whose risk increased at 51-73 years (odds ratio 4.639, P=0.056), but not among women (odds ratio 1.952). It then increased significantly (P<0.01) for both sexes aged at least 74 years. I-FOBTs identified most CRCs diagnosed within 36 months of follow-up with sensitivity similar to that of initial colonoscopy, with neither test identifying every CRC patient. Sex and age influence results and need consideration when planning population screening.

Comparison and combination of blood-based inflammatory markers with faecal occult blood tests for non-invasive colorectal cancer screening

Background:Faecal occult blood tests (FOBTs) are widely used for colorectal cancer (CRC) screening. Blood-based inflammatory markers have been suggested as alternative or supplementary non-invasive CRC screening tests.Methods:Among 179 CRC patients, 193 people with advanced adenoma and 225 people free of neoplasm, C-reactive protein (CRP), serum CD26 (sCD26), complement C3a anaphylatoxin and tissue inhibitor of metalloproteinases 1 (TIMP-1) levels in blood were measured by ELISA tests, and an immunochemical FOBT (iFOBT) and a guaiac-based FOBT were performed. Receiver operating characteristic curves were constructed and the areas under the curves (AUCs) were compared.Results:The blood levels of CRP, sCD26 and TIMP-1 showed statistically significant differences between CRC patients and neoplasm-free participants, and levels of TIMP-1 were furthermore significantly elevated in advanced adenoma patients. For the four inflammatory markers, AUCs ranged from 0.52 to 0.62 for CRC detection and from 0.50 to 0.58 for advanced adenomas detection, compared with AUCs of 0.90 and 0.68 for the iFOBT. At 97% specificity, blood markers showed much lower sensitivities than FOBTs. Combining inflammatory markers with the iFOBT increased the AUC for advanced adenomas.Conclusion:These blood-based markers do not seem to be an alternative to FOBT-based CRC screening. The potential use of these and other blood-based tests in combination with iFOBT might deserve further attention.

Prevalence of adenomas and advanced adenomas in patients in the 40- to 49-year age group undergoing screening colonoscopy because of a family history of adenoma/polyp in a first-degree relative

Per current guidelines, patients with a first-degree relative (FDR) with adenomas should get screened at age 40. Data on the prevalence of adenomas and advanced adenomas (AAs) in these patients are lacking. To examine the prevalence of adenomas and AAs in 40- to 49-year-old individuals undergoing screening colonoscopy because of a family history (FH) of polyps and to compare these data with those of a control population of similar age. Retrospective cross-sectional study. Tertiary care academic medical center and Veterans Affairs medical center. Study subjects included all 40- to 49-year-old asymptomatic individuals undergoing initial screening colonoscopy at our institution from January 1, 2006, to June 1, 2009, because of an FDR with polyps. The control population consisted of all 40- to 49-year-old individuals who underwent their first colonoscopy during the same period because of abdominal pain, diarrhea, or constipation without an FH of polyps or colorectal cancer. Colonoscopy. The prevalence of adenomas of any size, AAs, and risk factors associated with adenomas. The prevalence of adenomas was greater in the FH of polyps group (n = 176) compared with the control sample (n = 178) (26.7% vs 13.5%; P = .002) but was not statistically greater for AAs (5.7% vs 3.4%; P = .3). After adjusting for confounders, FH of a polyp was associated with an increased prevalence of adenomas (odds ratio 2.8 [95% CI, 1.4-5.5]). Limited data on polyp histology in FDRs and limited sample size. Among 40- to 49-year-old patients undergoing screening colonoscopy because of an FDR with polyps, the prevalence of adenomas was greater than in a control population. Prospective research is needed to quantify the prevalence of AAs in this group and to determine whether these individuals should undergo screening colonoscopy at age 40.

Inadequate Bowel Preparation Increases Missed Polyps

See Effect of the Bowel Preparation Status on the Risk of Missing Polyp and Adenoma during Screening Colonoscopy: A Tandem Colonoscopic Study Sung Noh Hong, In Kyung Sung, Jeong Hwan Kim, et al., on page 404-411 Recently, the demand of colonoscopy has been increasing rapidly due to the social interest for screening of colorectal cancer (CRC). This phenomenon is associated with the fact that colonoscopy is the most useful method for the detection and removal of colorectal polyps and that colonoscopic polypectomy significantly reduces the incidence and mortality of CRC.1,2 Although there are several screening modalities available for CRC, colonoscopy is considered the most effective method due to the ability of immediate polypectomy and biopsy of abnormal findings. Despite these remarkable features, the effectiveness of colonoscopy on the unconverted mortality of proximal colon cancer and the development of interval cancer are still in question. In addition, previous tandem colonoscopy studies reported the miss rates ranging from 12% to 24% for overall adenomas and between 0% and 6% for adenomas of ≥1 cm.3,4 Although most colonoscopists already expect that polyps can be missed during colonoscopy, these results suggest that colonoscopy is no more infallible for the detection of colorectal neoplasms. In order to obtain clear image during colonoscopy, adequate colon preparation, defined as the ability to detect polyps of 5 mm or larger,5 is essential. If bowel preparation is poor, it leads to prolonged examination time, incomplete procedure, and more importantly, missed significant lesions. Suboptimal bowel preparation has actually taken considerable portions of all colonoscopic examinations. Recently, two studies investigated the relationship between missing polyps and suboptimal bowel preparation.6,7 The results of these two studies suggested that suboptimal preparation at index colonoscopy for screening induced increased adenoma miss rate (AMR) and advanced adenoma miss rate (AAMR) despite having reached the current target adenoma detection rate (42% and 27%, 47.9% and 18%, respectively). Also, Chokshi et al.7 reported that 80% of missed advanced adenomas in patients with suboptimal preparation were located in the proximal colon. This result can be explained by the fact that missed adenomas on the right side of the colon have sessile morphology, which may be difficult to detect specifically after suboptimal bowel preparation. In an article published in the Clinical Endoscopy, Hong et al.8 reported a study suggesting that the risk of missing polyps and adenomas during screening colonoscopy is significantly affected by the bowel preparation status and that the patients with poor/inadequate bowel preparation were independently associated with an increased risk of missed polyp, missed adenoma, and missed advanced adenoma compared to the patients with excellent bowel preparation. In this study, AMR and AAMR in patients with suboptimal (poor/inadequate) bowel preparation were 47% and 37%, respectively, which were similar to the previous studies;7,8 furthermore, the rates were high even in patients with a well-prepared colon (21% to 27%, 9% to 18%, respectively). The patients with poor/inadequate bowel preparation were also independently associated with increased risks of missed polyp, missed adenoma, and missed advanced adenoma compared to the patients with excellent bowel preparation. As mentioned by the authors, the limitations of this study is the inflation of the overall miss rate (AMR and AAMR), which might be associated with the fact that all patients had one or more adenomas (≥5 mm), patients with ≥10 polyps were excluded, and tandem colonoscopies were performed by different colonoscopists in some patients. In addition, higher AMR and AAMR than previous tandem colonoscopy even in the patients with a well-prepared colon may be associated with the lack of high-quality colonoscopy, such as adequate withdrawal time and careful examination of the whole surface. Also, the location, shape and histology of missed advanced adenoma among bowel preparation status were not investigated in this study. Thus, it is necessary to give a supplementary explanation and make more precise investigation about these aspects. In conclusion, inadequate bowel preparation is clearly related with increased missed polyps. Current recommendations for postpolypectomy colonoscopy surveillance interval essentially require adequate bowel preparation, and if the bowel preparation was inadequate, repeat colonoscopy should be performed after adequate preparation as soon as possible considering low patient-return for repeat colonoscopy, reduction of secondary inadequate preparation, and legal problems related with interval cancer. Efforts to improve the quality of bowel preparation, including patient education, should be continued to obtain high-quality colonoscopy.

The Effects of Family History of Colorectal Cancer on the Development of Colorectal Adenoma

Early detection of polyp is important for the prevention of colorectal cancer (CRC). There have been few studies to investigate the relationship between colorectal adenoma and family history of CRC (FHCRC) in Korea. The aim of this study was to identify the relationship between colorectal adenoma and FHCRC. Between March 2009 and September 2010, 225 patients with adenomatous polyps were included. Their medical records with clinical history and size, numbers, histology of polyps were reviewed. Immunohistochemical staining using Bcl-2, Bax, p-AKT, NF-κB, and β-catenin antibodies were performed. We compared the histology of adenoma and expression of immunohistochemical staining according to the existence of FHCRC. The incidence of colorectal adenoma increased in case of FHCRC (p=0.029). In patients with FHCRC, the mean age of patients was 49 years old and younger than patients without FHCRC. In addition in patients with FHCRC, the incidence of advanced adenoma was significantly higher than in patients without FHCRC (p=0.001). The expression of Bax was significantly lower in patients with FHCRC than without FHCRC (p=0.046). There was a tendency for polyp to develop in their younger ages and to be more advanced adenomas in patients with FHCRC. The low expression of Bax, tumor suppressor gene, might be associated with the development of polyps in patient with FHCRC. Therefore, patients with FHCRC may be better to start screening colonoscopy earlier than patient without FHCRC.

High-definition colonoscopy and risk factors for recurrence of advanced adenomas in patients with a personal history of polyps

Postpolypectomy surveillance is one of the most common reasons for performing colonoscopy. Our purpose was to assess characteristics of basal adenomas related to the recurrence of advanced adenomas, and to compare the patterns observed in recurrent adenomas with the use of conventional colonoscopy (CC) (1995-1998 period) or high-definition colonoscopy (HDC) (2005-2008 period). Analyses were based on 612 patients with recurrent adenomas (n=306) or no adenomas (control group; n=306), with at least two follow-up colonoscopies. A total of 56 patients with recurrent adenomas during the 1995-1998 period were compared with 116 patients in the 2005-2008 period. Morphology, size, location, and pathological diagnosis of each polyp were recorded. Multiple logistic regressions were used to calculate relative risk (RR) for recurrence. The study population was predominantly male (68.8%), with a mean age of 61.1 years and a mean follow-up period of 90.6±59.4 months. Advanced adenomas were found during follow-up evaluation in 120 patients (39.2%). The RR of advanced adenoma recurrence was 1.64 [95% confidence interval (CI): 1.01-2.64] among patients with baseline high-risk adenoma and 0.61 (CI: 0.38-0.98) among those with baseline low-risk adenoma. In the multivariable analyses, patients with larger adenomas were more likely to develop advanced recurrence (RR 1.02; 95% CI: 1.01-1.04). Both techniques (CC and HDC) detected a similar number (2.37±3.28 vs. 3.11±4.63; P=0.406) at qualifying colonoscopy. During follow-up both periods showed comparable adenoma characteristics. Patients with larger adenomas were more likely to develop advanced recurrence. HDC did not detect significantly more adenomas than CC. Characteristics of recurrent adenomas were comparable in both periods.

S1981 Routine MSI-Analysis in Advanced Adenomas in Patients Younger Than 45 Years Leads to the Identification of More Patients at High Risk for Lynch Syndrome

S1981 Routine MSI-Analysis in Advanced Adenomas in Patients Younger Than 45 Years Leads to the Identification of More Patients at High Risk for Lynch Syndrome

Recurrence and surveillance of colorectal adenoma after polypectomy in a southern Chinese population

Repeat colonoscopy is often performed within a short time after polypectomy due to the fear that colorectal adenomas were missed during the initial colonoscopy or that new adenomas have developed. The aim of this study was to estimate the actual recurrence rate of adenoma and its association with the length of the surveillance interval after polypectomy in a southern Chinese population. A total of 1,356 patients undergoing endoscopic polypectomy and completing three or more surveillence colonoscopies between 1976 and 2007 were retrospectively analyzed. The recurrence rates of adenoma and advanced adenoma and surveillance intervals after polypectomy were identified based on the features of adenomas detected on initial colonoscopy. The recurrence rates of advanced adenoma in patients with non-advanced adenoma on the initial colonoscopy were 0.9, 3.9, 5.8, and 29.2% during surveillance intervals of 1-3, 3-5, 5-10, and 10-20 years post-initial colonoscopy; for patients with advanced adenoma on the initial colonoscopy, the recurrence rates were 3.8, 13.1, 34.7, and 52.0% during the same surveillance intervals, respectively. Older age (p < 0.05 for trend) and male sex [hazard ratio (HR) 2.11, 95% confidence interval (CI) 1.27-3.53] were significantly associated with recurrence for advanced adenoma, as were the size and number of baseline adenoma (p < 0.05 for trend), tubulovillous, villous adenoma (HR 2.57, 95% CI 1.24-5.32), and high-grade dysplasia (HR 1.61, 95% CI 1.07-2.42). When 5% of patients had recurring advanced adenoma, the surveillance interval was estimated to be 6.9 (95% CI 6.3-12.2) years in the low-risk group and 3.0 (95% CI 2.7-3.2) years in the high-risk group. Among our patient group, the recurrence of advanced adenoma after polypectomy increased with the length of the surveillance interval. Based on our results, a 3-year follow-up of patients after polypectomy could be effective in preventing the recurrence of advanced adenoma in high-risk patients.

Family History of Single First-Degree Relative with Colorectal Cancer Does Not Predict Increased Risk of Advanced Adenomas On Screening Colonoscopy in a Southwestern U.S. Population

Background and Aims: A family history of colorectal cancer is considered a risk factor for finding advanced adenomas on colonoscopy. The expected outcome for screening colonoscopy in patients with a family history is not well established in all populations. Methods: We designed a large, prospective study of an unselected population in San Diego, California to assess the impact of a family history of colorectal cancer on the prevalence of advanced adenomas on screening colonoscopy. Asymptomatic patients between ages 40 to 89 referred for screening colonoscopy were included. Family history of colorectal cancer was defined as having at least one first-degree relative with colorectal cancer. Family history was obtained from review of medical records. Advanced adenoma was defined as having size ≥ 10 mm, villous features, dysplasia or carcinoma. Results: We evaluated 6,185 patients referred for colonoscopy between January 2005 and July 2006. 4,377 patients met the inclusion criteria. 833 (19%) had an adenoma and 225 (5.1%) had an advanced adenoma, 10 of which had carcinoma. The 4,377 patients were divided into 469 with and 3906 without a family history of colorectal cancer. Of the 469 patients with a family history, 31 (6.6%) had an advanced adenoma, none of which were carcinomas. Of the 3,906 without a family history, 194 (5.0%) had an advanced adenoma including 10 carcinomas (0.3%). The odds ratio for finding an advanced adenoma in patients with a family history was 1.35 (95%CI = 0.92-2.00; p = .18). If the affected relative was <60 at age of diagnosis the odds ratio was 1.52 (95%CI = 0.85-2.72). These differences were not statistically significant. An advanced adenoma was found in 26/428 (6.1%) of patients with a single affected first-degree relative (OR 1.22; 95%CI = 0.80-1.86; p = .41), 1/33 (3.0%) of patients with an affected first and second-degree relative (OR 0.58; 95%CI = 0.08-4.28; p = 1) and 4/18 (22.2%) of patients with two affected first-degree relatives (OR 5.42; 95%CI = 1.77-16.6; p = .02). When separated by gender, 118/1829 (6.5%) of men and 107/2548 (4.2%) of women had an advanced adenoma (OR 1.57; 95%CI = 1.20-2.06; p = .002). Conclusions: A family history of one first-degree relative with colorectal cancer did not predict a higher prevalence of advanced adenomas in asymptomatic patients at screening colonoscopy in this Southwestern cohort. Significant predictors of advanced adenomas were family history of two first-degree relatives with colorectal cancer and male gender. These data suggest the need to reassess the impact of a family history of a single first-degree relative with colorectal cancer on the prevalence of advanced adenomas in regional populations.

A Quantitative Immunochemical Fecal Occult Blood Test for Colorectal Neoplasia

Guaiac-based fecal occult blood tests (FOBTs) for colorectal cancer screening are not specific for human hemoglobin and have low sensitivity. Automated-development, immunochemical FOBT is quality-controlled, is specific for human hemoglobin, and does not require diet restriction. To measure the sensitivity and specificity of quantitative immunochemical fecal hemoglobin measurements for detection of cancer and advanced adenoma in patients undergoing colonoscopy, to determine fecal hemoglobin thresholds that give the highest posttest probability for neoplasia, and to determine the number of immunochemical FOBTs needed. Prospective, cross-sectional study. Ambulatory endoscopy services of the main health medical organization in Tel Aviv, Israel. 1000 consecutive ambulatory patients--some asymptomatic but at increased risk for colorectal neoplasia and some symptomatic--who were undergoing elective colonoscopy and volunteered to prepare immunochemical FOBTs. The hemoglobin content of 3 bowel movements was measured, and the highest value was compared with colonoscopy findings. Sensitivity, specificity, predictive values, likelihood ratios, and 95% CIs of fecal hemoglobin measurements for clinically significant neoplasia, their relationship to the amount of fecal hemoglobin measured, and the number of immunochemical FOBTs performed. Colonoscopy identified clinically significant neoplasia in 91 patients (cancer in 17 patients and advanced adenomas in 74 patients). Using 3 immunochemical FOBTs and a hemoglobin threshold of 75 ng/mL of buffer, sensitivity and specificity were 94.1% (95% CI, 82.9% to 100.0%) and 87.5% (CI, 85.4% to 89.6%), respectively, for cancer and 67% (CI, 57.4% to 76.7%) and 91.4% (CI, 89.6% to 93.2%), respectively, for any clinically significant neoplasia. The fecal sampling method is standardized, but the sample size depends on fecal consistency. Some patients were tested while discontinuing aspirin and anticoagulant therapies. Study patients were at increased risk, and results might not apply to average-risk populations. Quantitative immunochemical FOBT has good sensitivity and specificity for detection of clinically significant neoplasia. Test performance in screening average-risk populations is not known.

PERFORMING A COLONOSCOPY 12 MONTHS AFTER SURGERY FOR COLORECTAL NEOPLASIA

There appears to be acceptance that following up patients after surgery for colorectal neoplasia is of value. However, specific issues relating to which investigations to perform and how often remain unresolved. The aim of this project was to evaluate the clinical utility of performing a colonoscopy 12 months after curative surgery for colorectal neoplasia. Patients were selected if they had undergone a curative resection for colorectal neoplasia, and if they had had a completed colonoscopy prior to surgery. Study endpoints included: (i) compliance with follow up; (ii) the prevalence, total number, size, and histology of polyps; and (iii) identification of recurrent or metachronous cancer. The study group included 253 patients of mean age 69.7 years (SD 11.6) and a male : female ratio of 1.4:1.0. Colonoscopies were completed on 90% of patients at a mean of 1.1 years following surgery. A total of 149 polyps were identified in 30% of patients. On histology, 42% were tubular adenomas, 6% tubulo-villous adenomas, 7% were villous adenomas, and 37% were hyperplastic. Advanced adenomas were identified in 7.9% of patients (95% CI 4.8-12.1%). No recurrent or metachronous cancers were identified. We have observed a high prevalence of advanced adenomas in patients undergoing a 12-month, follow-up colonoscopy after curative surgery for colorectal neoplasia. The significance of these observations requires further evaluation.