The National Polyp Study

Should all endoscopically excised rectal polyps be tattooed? A plea for localization

BACKGROUND

More than 5-8 % of endoscopically removed rectal polyps presumed to be benign contain invasive carcinoma. Tattooing has been advocated for follow-up localization of the resection site. Despite proven benefits, the authors propose that tattooing is not routinely performed when benign-appearing rectal polyps are endoscopically excised, thereby confounding management when invasive cancer is found. The secondary goal of the study was to determine the frequency of localization, polyp characteristics, and accuracy of predicting malignant potential at the authors' institution.

METHODS

All patients with rectal neoplasia discovered during endoscopic polypectomy from 1 January 2003 to 1 August 2010 were retrospectively identified from Temple University Hospital's Tumor Registry. Demographic and clinical data were extracted from medical records including polyp size, gross appearance, pathology, resection margins, location based on preoperative colonoscopy, initial removal technique, tattoo performance, and ensuing procedures.

RESULTS

During the study period, 49 patients had colonoscopic excision of presumed benign rectal polyps with ensuing diagnosis of neoplasia in the specimen. The malignant histology included adenocarcinoma (n = 5), carcinoma in situ (n = 21), carcinoid (n = 22), and composite carcinoid (n = 1). Only two polyps were tattooed at the initial polypectomy. Three polyps were "suspicious for malignancy." None of the suspicious polyps were tattooed. One of the suspicious lesions was an adenocarcinoma, and the remaining two were benign. The distance from the anal verge was noted in only seven patients. The predominant excision technique was hot snare polypectomy (n = 29). None of the incomplete polyp excisions for 15 patients were "suspicious for malignancy" or tattooed. Several strategies were used to manage incomplete resections including surveillance (40 %), repeat colonoscopic polypectomy (27 %), and surgery (33 %).

CONCLUSIONS

Most malignant rectal polyps are neither diagnosed nor tattooed at initial colonoscopy. Moreover, the distance of the polyp from the anal verge is rarely measured, and gross characteristics are not well described. Tattooing of all endoscopically excised rectal polypectomy sites would avoid confounding of subsequent identification and management.

The Your Disease Risk Index for colorectal cancer is an inaccurate risk stratification tool for advanced colorectal neoplasia at screening colonoscopy

Tailoring the use of screening colonoscopy based on the risk of advanced colorectal neoplasia (ACN) could optimize the cost-effectiveness of colorectal cancer (CRC) screening. Our goal was to assess the accuracy of the Your Disease Risk (YDR) CRC risk index for stratifying average risk patients into low- versus intermediate/high-risk categories for ACN. The YDR risk assessment tool was administered to 3,317 asymptomatic average risk patients 50 to 79 years of age just before their screening colonoscopy. Associations between YDR-derived relative risk (RR) scores and ACN prevalence were examined using logistic regression and χ(2) analyses. ACN was defined as a tubular adenoma ≥1 cm, tubulovillous or villous adenoma of any size, and the presence of high-grade dysplasia or cancer. The overall prevalence of ACN was 5.6%. Although YDR-derived RR scores were linearly associated with ACN after adjusting for age and gender (P = 0.033), the index was unable to discriminate "below average" from "above/average" risk patients [OR, 1.01; 95% confidence interval (CI), 0.75-1.37]. Considerable overlap in rates of ACN was also observed between the different YDR risk categories in our age- and gender-stratified analyses. The YDR index lacks accuracy for stratifying average risk patients into low- versus intermediate/high-risk categories for ACN.

Impact of comorbidity on colorectal cancer screening cost-effectiveness study in diabetic populations

BACKGROUND

Although comorbidity has been shown to affect the benefits and risks of colorectal cancer (CRC) screening, it has not been accounted for in prior cost-effectiveness analyses of CRC screening.

OBJECTIVE

To evaluate the impact of diagnosis of diabetes mellitus, a highly prevalent comorbidity in U.S. adults aged 50 and older, on health and economic outcomes of CRC screening.

DESIGN

Cost-effectiveness analysis using an integrated modeling framework.

DATA SOURCES

Derived from basic and epidemiologic studies, clinical trials, cancer registries, and a colonoscopy database.

TARGET POPULATION

U.S. 50-year-old population.

TIME HORIZON

Lifetime.

PERSPECTIVE

Costs are based on Medicare reimbursement rates.

INTERVENTIONS

Colonoscopy screening at ten-year intervals, beginning at age 50, and discontinued after age 50, 60, 70, 80 or death.

OUTCOME MEASURES

Health outcomes and cost effectiveness.

RESULTS OF BASE-CASE ANALYSIS

Diabetes diagnosis significantly affects cost-effectiveness of CRC screening. For the same CRC screening strategy, a person without diabetes at age 50 gained on average 0.07-0.13 life years more than a person diagnosed with diabetes at age 50 or younger. For a population of 1,000 patients diagnosed with diabetes at baseline, increasing stop age from 70 years to 80 years increased quality-adjusted life years (QALYs) gained by 0.3, with an incremental cost-effectiveness ratio of $206,671/QALY. The corresponding figures for 1,000 patients without diabetes are 2.3 QALYs and $46,957/QALY.

RESULTS OF SENSITIVITY ANALYSIS

Cost-effectiveness results are sensitive to cost of colonoscopy and adherence to colonoscopy screening.

LIMITATIONS

Results depend on accuracy of model assumptions.

CONCLUSION

Benefits of CRC screening differ substantially for patients with and without diabetes. Screening for CRC in patients diagnosed with diabetes at age 50 or younger is not cost-effective beyond age 70. Screening recommendations should be individualized based on the presence of comorbidities.

Markers of the APC/β-catenin signaling pathway as potential treatable, preneoplastic biomarkers of risk for colorectal neoplasms

BACKGROUND

Malfunctioning of the adenomatous polyposis coli (APC)/β-catenin signaling pathway is both an early and common event in sporadic colorectal cancer. To assess the potential of APC/β-catenin signaling pathway markers as treatable, preneoplastic biomarkers of risk for colorectal neoplasms, we conducted a pilot colonoscopy-based case-control study (51 cases and 154 controls) of incident, sporadic colorectal adenoma.

METHODS

We evaluated APC, β-catenin, and E-cadherin expression in normal mucosa from the rectum and ascending and sigmoid colon using automated immunohistochemical and quantitative image analysis. Diet, lifestyle, and medical history were assessed with validated questionnaires.

RESULTS

In the normal rectal mucosa, the ratio of the proportion of APC expression in the upper 40% of crypts with total β-catenin expression (APC/β-catenin score) was 14.3% greater in controls than in cases [P = 0.02; OR, 0.40; 95% confidence interval (CI), 0.14-1.14]. Compared with controls, in cases, APC expression was 3.2% lower, β-catenin expression was 3.0% higher, and E-cadherin expression was 0.7% lower; however, none of these differences were statistically significant. The APC/β-catenin score statistically significantly differed according to categories of plausible risk factors for colorectal cancer [e.g., it was 17.7% higher among those with 25(OH) vitamin D(3) concentrations ≥ 27 ng/mL].

CONCLUSIONS

These preliminary data suggest that the combined expression of APC and β-catenin in the normal rectal mucosa may be associated with risk for incident, sporadic colorectal neoplasms, as well as with modifiable risk factors for colorectal neoplasms.

IMPACT

Our results may help advance the development of treatable, preneoplastic biomarkers of risk for colorectal neoplasms.

Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths

BACKGROUND

In the National Polyp Study (NPS), colorectal cancer was prevented by colonoscopic removal of adenomatous polyps. We evaluated the long-term effect of colonoscopic polypectomy in a study on mortality from colorectal cancer.

METHODS

We included in this analysis all patients prospectively referred for initial colonoscopy (between 1980 and 1990) at NPS clinical centers who had polyps (adenomas and nonadenomas). The National Death Index was used to identify deaths and to determine the cause of death; follow-up time was as long as 23 years. Mortality from colorectal cancer among patients with adenomas removed was compared with the expected incidence-based mortality from colorectal cancer in the general population, as estimated from the Surveillance Epidemiology and End Results (SEER) Program, and with the observed mortality from colorectal cancer among patients with nonadenomatous polyps (internal control group).

RESULTS

Among 2602 patients who had adenomas removed during participation in the study, after a median of 15.8 years, 1246 patients had died from any cause and 12 had died from colorectal cancer. Given an estimated 25.4 expected deaths from colorectal cancer in the general population, the standardized incidence-based mortality ratio was 0.47 (95% confidence interval [CI], 0.26 to 0.80) with colonoscopic polypectomy, suggesting a 53% reduction in mortality. Mortality from colorectal cancer was similar among patients with adenomas and those with nonadenomatous polyps during the first 10 years after polypectomy (relative risk, 1.2; 95% CI, 0.1 to 10.6).

CONCLUSIONS

These findings support the hypothesis that colonoscopic removal of adenomatous polyps prevents death from colorectal cancer. (Funded by the National Cancer Institute and others.).

Prevalence and distribution of adenomas in black Americans undergoing colorectal cancer screening

BACKGROUND

The American College of Gastroenterology recommends colorectal cancer (CRC) screening for average-risk black Americans ages 45-49. This is based on this group's younger age for the development of adenomas and CRC. Our purpose was to determine the yield of CRC screening in average-risk black Americans including those <age 50. We also aimed to identify whether there was a higher prevalence of proximal adenomas in black Americans.

STUDY

This was a cross-sectional, retrospective study. All colonoscopy examinations from 2007 through 2010 were reviewed. Complete examinations with a good/excellent preparation in average-risk black patients 45-49 were selected. We excluded patients with signs, symptoms, or family history of CRC. Defined two control groups: average-risk black and white patients ages 50-59 who completed a colonoscopy during the same period. Patient's height, weight, and use of statin medications and aspirin were recorded. Patients currently using tobacco at least weekly were identified.

RESULTS

There were 1,230 patients with an adenoma for a prevalence of 40.7%. We included 304 black Americans 45-49 years, 669 black Americans 50-59 years, and 257 whites 50-59 years. There was no association between race/age group and the presence of at least one adenoma, proximal adenomas, or advanced adenomas. In regression modeling, both male sex and active smoking were associated with all three outcomes.

CONCLUSIONS

Male sex and active smoking are risk factors for prevalent adenomas, proximal adenomas, and advanced adenomas. The prevalence of adenomas is similar in black Americans 45-49 compared to older black and white patients. We did not find that the recognized proximal distribution of CRC in black Americans parallels a similar distribution in adenomas in this group.

[Standardized and structured histopathological evaluation of colorectal polyps: a practical checklist against the background of the new WHO classification]

Gastroenterologists removing colorectal polyps expect standardized and well-structured pathological reports, providing them with all relevant data for the further clinical management of the patient. Over the last year, a task force of clinicians and pathologists has developed a checklist to improve and harmonize endoscopic and pathological reporting of colorectal polyps. This checklist concentrates more on concrete recommendations from evidence-based guidelines and established international classifications for daily practice rather than detailed molecular pathological pathways of carcinogenesis. These recommendations are based on the current S3 guidelines for colorectal cancer (the chapter entitled "Management of colorectal polyps"), the histomorphological consensus manuscript of the GI working group of the German Society for Pathology, as well as the current WHO classification for tumors of the digestive system.

Preventing bowel cancer: an insight for clinicians

Worldwide, colorectal cancer causes 610,000 deaths annually with 38,000 new cases diagnosed in the UK and 16,000 deaths each year. The prognosis is directly related to the staging of the cancer at diagnosis, with an overall 5-year survival rate of approximately 50%. However, for localized disease the figure is much higher at 90%, although unfortunately many cancers present at an advanced stage. Importantly, there is the potential to reduce the incidence because most tumours arise from premalignant adenomatous polyps, which if detected and removed interrupts the adenoma-adenocarcinoma sequence. In addition, identifying colorectal cancer at an early stage can impact on the mortality rates for this neoplasm. The current screening options for bowel cancer include analysis of stool for occult blood and endoscopic assessments of the colorectum, including flexible sigmoidoscopy and full colonoscopy. The aim of this review is to present information on the natural history of colorectal cancer, the evaluation of the different screening modalities and the current faecal occult blood screening program within the UK National Health Service, and to discuss how dietary factors and aspirin may affect aetiology.

Clinical features and prognosis of early colorectal cancer treated by endoscopic mucosal resection

BACKGROUND AND AIMS

The incidence of early colorectal cancer (ECC) has been increasing. The aim of this study was to evaluate the clinical outcome and prognosis of ECC treated by endoscopic mucosal resection (EMR).

METHODS

A total of 129 ECC patients who were initially treated by EMR between April 2005 and August 2007 were enrolled. Clinicopathological characteristics and prognoses were evaluated retrospectively.

RESULTS

En bloc resection was performed in 85% of ECC patients, and piecemeal resection was performed in 15% of patients. Clear lateral and deep margins were achieved in 86% of cases. Of the 129 patients, 64 were found to have intramucosal cancer and 65 had submucosal cancer. Clinical characteristics were not different between patients with intramucosal cancer and submucosal cancer; however, poor differentiation and the absence of background adenoma showed significant association with submucosal cancer. Seven patients with submucosal cancer underwent subsequent surgical resection; five had lymphovascular invasion or a positive resection margin, one had perforation, and one patient requested surgical resection. Of these seven patients, one had residual cancer and two had lymph node metastasis. All patients with intramucosal cancer had no recurrence during the follow-up period. Seven patients with submucosal cancer showed adverse outcomes within 3 years, such as residual/recurrence of primary cancer or lymph node metastasis; five showed lymphovascular invasion or a positive deep margin, and two had no histological risk factors.

CONCLUSIONS

Our results suggest that intramucosal cancer shows good prognosis, and a cure could be expected after EMR; however, adverse outcomes can occur in submucosal cancer. Therefore, meticulous endoscopic follow up is needed in patients with submucosal cancer for at least 3 years after EMR.

Korean type 2 diabetes patients have multiple adenomatous polyps compared to non-diabetic controls

We tested the correlation between diabetes and aggressiveness of colorectal polyps in diabetic patients and matched non-diabetic controls. We retrospectively studied 3,505 type 2 diabetes (T2DM) patients without gastrointestinal symptoms who underwent colonoscopy for colorectal cancer at Samsung Medical Center, Seoul, Korea from August 1995 to August 2009. We matched 495 non-diabetic subjects with colon polyps to the diabetic patients in whom polyps were detected by year of colonoscopy, age, sex and body mass index (BMI). Among the 3,505 T2DM patients screened, 509 were found to have 1,136 colon polyps. Those with diabetes had a greater proportion of adenomatous polyps (62.8% vs 53.6%) compared to the control. Multivariate logistic regression analysis identified DM, male gender, age and BMI as independent risk factors for multiple polyps (more than three polyps). Polyp multiplicity in diabetic patients was significantly associated with male gender (OR 2.360, P = 0.005), age (OR 1.033, P = 0.005) and BMI (OR 1.077, P = 0.028). Neither aspirin nor metformin use affected either size or number of polyps in diabetic patients. Male patients older than 65 yr with T2DM and BMI greater than 25 have increased risk for multiple adenomatous polyps and should be screened with colonoscopy to prevent colorectal cancer.

Differentiating small polyp histologies using real-time screening colonoscopy with Fuji Intelligent Color Enhancement

BACKGROUND & AIMS

There are limited data describing the performance of Fuji Intelligent Color Enhancement (FICE, EC 590 ZW; Fujinon Inc, Saitama, Japan) for differentiating polyp histologies during screening colonoscopy. We evaluated the ability of an endoscopist to diagnose small polyp histology during a screening colonoscopy using FICE.

METHODS

A prospective study was performed on 763 consecutive, asymptomatic subjects who were undergoing screening colonoscopy. Pit patterns and vascular patterns were used to predict the histology of 525 polyps (mean size, 4.5 ± 2.2 mm, 315 adenomas) of less than 10 mm using FICE with high magnification and without. The performances of the FICE analyses were calculated and compared with the results from the histopathology.

RESULTS

The overall accuracy achieved by FICE with high magnification in the diagnosis of adenomas of less than 10 mm (87.0%) was significantly greater than that achieved without high magnification (80.4%; P < .05). Moreover, the improvement of accuracy attained when using high-magnification FICE was most pronounced and significant compared without using high-magnification FICE in the diagnosis for diminutive polyps (≤5 mm; 85.4% vs 79.1%; P < .05). Among all types of adenomas, the sensitivity of FICE was lowest for sessile serrated adenomas (38.5% vs 89.4%; P < .01), even when FICE was used with high magnification.

CONCLUSIONS

FICE with high magnification is better for differentiating the histology of small polyps during screening colonoscopy than FICE without high magnification, especially for diminutive polyps. Large-scale studies are needed to improve the identification of serrated adenomas and small diminutive polyps using FICE.

Matching colonoscopy and pathology data in population-based registries: development of a novel algorithm and the initial experience of the New Hampshire Colonoscopy Registry

BACKGROUND

The quality of polyp-level data in a population-based registry depends on the ability to match each polypectomy recorded by the endoscopist to a specific diagnosis on the pathology report.

OBJECTIVE

To review impediments encountered in matching colonoscopy and pathology data in a population-based registry.

DESIGN

New Hampshire Colonoscopy Registry data from August 2006 to November 2008 were analyzed for prevalence of missing reports, discrepancies between colonoscopy and pathology reports, and the proportion of polyps that could not be matched because of multiple polyps submitted in the same container.

SETTING

New Hampshire Colonoscopy Registry.

PATIENTS

This study involved all consenting patients during the study period.

INTERVENTION

Develop an algorithm for capturing number, size, location, and histology of polyps and for defining and flagging discrepancies to ensure data quality.

MAIN OUTCOME MEASUREMENTS

The proportion of polyps with no assumption or discrepancy, the proportion of patient records eligible for determining the adenoma detection rate (ADR), and the number of patients with ≥3 adenomas.

RESULTS

Only 50% of polyps removed during this period were perfectly matched, with no assumption or discrepancy. Records from only 69.9% and 29.7% of eligible patients could be used to determine the ADR and the number of patients with ≥3 adenomas, respectively.

LIMITATIONS

Rates of missing reports may have been higher in the early phase of establishment of the registry.

CONCLUSION

This study highlights the impediments in collecting polyp-level data in a population-based registry and provides useful parameters for evaluating the quality and accuracy of data obtained from such registries.

Prevalence of advanced adenomas in small and diminutive colon polyps using direct measurement of size

BACKGROUND AND AIMS

Most studies reporting polyp size use visual estimates. Determining the prevalence of advanced histology based on direct measurement of polyp size may help guide the management of polyps found at optical colonoscopy (OC) and CT colonography (CTC).

METHODS

We designed a large, prospective study to assess the prevalence of advanced adenomas based on direct measurement of polyp size by a certified pathologists' assistant as reported in the pathology report. Patients between 40 and 89 years of age who presented for screening colonoscopy were included in our study. Advanced adenomas were defined as ≥10 mm or ≥25% villous features, high grade dysplasia or cancer. Polyps were divided by size into three groups: diminutive (≤5 mm), small (6-9 mm) and large (≥10 mm). If more than one adenoma was present, the most advanced was used for analysis.

RESULTS

We evaluated 6,905 consecutive patients referred for colonoscopy between January 2005 and December 2006. Of the 4,967 who met the inclusion criteria, the mean age was 58.8 and consisted of 59% women. Overall, 930 (18.7%) had an adenoma; 248 (5%) were advanced adenomas including 8 (0.16%) cancers. Of 89 polyps≥10 mm, 76 (85%) had advanced histology; of 247 polyps 6-9 mm, 67 (27%) were advanced; of 1,025 polyps ≤5 mm, 105 (10%) were advanced. Thus, 172 of 248 (69%) patients with advanced adenomas had small or diminutive adenomas.

CONCLUSIONS

Our data indicate the majority (69%) of advanced adenomas are <10 mm. Even among polyps≤5 mm, there was an appreciable prevalence of advanced adenomas (10%). These findings may help guide the management of sub-centimeter colon polyps found by OC or CTC.

Proceedings of a preliminary workshop at Gastro 2009--narrow banding imaging in digestive endoscopy: clinical outcome of classification (Omed-Jges Educational Meeting held on 22 November, 2009)

This publication reports the proceedings of the preliminary meeting of the working party that met at Gastro 2009 during the World Congress in London. The purpose of the preliminary meeting was to consider the areas that require attention, to discuss some of the findings that have already been published and to agree on the way forward. Our reason for publishing these proceedings is to stimulate interest in this venture and to provide the opportunity for input from the endoscopy community worldwide. The next meeting of the working party will be at the JGES Society meeting in Aomori in April 2011 when we hope to prepare a preliminary classification. This will be presented for general discussion and debate at the International Congress of Endoscopy (ICE) in Los Angeles in September 2011.

Detection of colorectal neoplasia by colonoscopy in average-risk patients age 40-49 versus 50-59 years

BACKGROUND

The USPSTF recommends beginning colorectal cancer screening at age 50. A recent study showed prevalence of colorectal adenomas among individuals aged 40-49 was similar to that among those aged 50-59.

AIM

To assess the prevalence of colorectal neoplasia, detected during colonoscopy, by age among average-risk patients.

METHODS

Nine-hundred and ninety-four colonoscopies were analyzed (247 ages 40-49, 747 ages 50-59). We included consecutive patients of ages 40-59 undergoing their first colonoscopy. Colonoscopies that did not reach the cecum and patients at increased risk of colorectal cancer were excluded. The primary endpoint was the prevalence of colorectal neoplasia by age. Secondary endpoints included the prevalence of colorectal neoplasia by gender, ethnicity, and BMI.

RESULTS

The prevalence of colorectal neoplasia was 12.1% in patients aged 40-49 and 22.6% in those aged 50-59. Compared with individuals aged 40-49 there was a significantly greater prevalence of adenomas (chi-squared = 12.72, P = 0.0004) and of advanced adenomas or cancer (chi-squared = 5.73, P = 0.01) in individuals aged 50-59. After adjusting for gender, race, and BMI the effect of age remained significant (OR 0.5, 95% CI 0.33-0.76). Higher BMI was associated with increased risk of colorectal neoplasia (OR 1.03, 95% CI 1.00-1.06). The number that had to be screened to detect one advanced lesion in the 40-49 age group was 49 compared with 20 in those aged 50-59.

CONCLUSION

Individuals aged 40-49 have a lower but measurable risk of colorectal neoplasia compared with those aged 50-59. Although there may be population subgroups for which screening below the age of 50 may be indicated, our results do not support lowering the age threshold for colonoscopy in the general population.

Feasibility of simultaneous computed tomographic colonography and fully automated bone mineral densitometry in a single examination

PURPOSE

To show the feasibility of calculating the bone mineral density (BMD) from computed tomographic colonography (CTC) scans using fully automated software.

MATERIALS AND METHODS

Automated BMD measurement software was developed that measures the BMD of the first and second lumbar vertebrae on computed tomography and calculates the mean of the 2 values to provide a per patient BMD estimate. The software was validated in a reference population of 17 consecutive women who underwent quantitative computed tomography and in a population of 475 women from a consecutive series of asymptomatic patients enrolled in a CTC screening trial conducted at 3 medical centers.

RESULTS

The mean (SD) BMD was 133.6 (34.6) mg/mL (95% confidence interval, 130.5-136.7; n = 475). In women aged 42 to 60 years (n = 316) and 61 to 79 years (n = 159), the mean (SD) BMDs were 143.1 (33.5) and 114.7 (28.3) mg/mL, respectively (P < 0.0001). Fully automated BMD measurements were reproducible for a given patient with 95% limits of agreement of -9.79 to 8.46 mg/mL for the mean difference between paired assessments on supine and prone CTC.

CONCLUSIONS

Osteoporosis screening can be performed simultaneously with screening for colorectal polyps.

The origins of colorectal carcinoma: specific nomenclature for different pathways and precursor lesions

BACKGROUND

The widespread application of molecular methods in pathology has yielded steady advances in our understanding of the origins of colorectal carcinoma. Multiple pathways of carcinogenesis have been demonstrated on the molecular level and visualized on the histopathological level. The WHO has accordingly proposed a number of new designations and terms, particularly for precursor lesions, in order to establish a uniform standard for clinical diagnosis. These should be put into practice at once.

METHODS

In this article, we explain the concept of intraepithelial neoplasia, which replaces the older concept of dysplasia. Moreover, we use this concept in describing a new mechanism of carcinogenesis for colorectal carcinoma, on the basis of a selective review of the literature. We estimate the frequency of precursor lesions according to the new concept using data from our own patient collective. Finally, we discuss the clinical consequences, which have been addressed in the German S3 guideline for colorectal carcinoma.

RESULTS

The new type of precursor lesion, called "sessile serrated adenoma" (SSA), accounts for some 7% of all adenomas in our patient collective and is usually found in the right hemicolon. Traditional serrated adenomas (TSA) made up 1% to 3% of our cases and were found mainly in the left hemicolon and rectum.

CONCLUSION

Our observations on the frequency and location of serrated adenomas accord with the initial findings published in the international literature. In view of the risk that serrated lesions will progress more rapidly, it is recommended that they should be completely removed, with follow-up at a short interval thereafter (three years according to the German S3 guidelines).

Analysis of mtDNA sequence variants in colorectal adenomatous polyps

Colorectal tumors mostly arise from sporadic adenomatous polyps. Polyps are defined as a mass of cells that protrudes into the lumen of the colon. Adenomatous polyps are benign neoplasms that, by definition display some characteristics of dysplasia. It has been shown that polyps were benign tumors which may undergo malignant transformation. Adenomatous polyps have been classified into three histologic types; tubular, tubulovillous, and villous with increasing malignant potential. The ability to differentially diagnose these colorectal adenomatous polyps is important for therapeutic intervention. To date, little efforts have been directed to identifying genetic changes involved in adenomatous polyps. This study was designed to examine the relevance of mitochondrial genome alterations in the three adenomatous polyps. Using high resolution restriction endonucleases and PCR-based sequencing, fifty-seven primary fresh frozen tissues of adenomatous polyps (37 tumors and 20 matched surrounding normal tissues) obtained from the southern regional Cooperative Human Tissue Network (CHTN) and Grady Memorial Hospital at Atlanta were screened with three mtDNA regional primer pairs that spanned 5.9 kbp. Results from our data analyses revealed the presence of forty-four variants in some of these mitochondrial genes that the primers spanned; COX I, II, III, ATP 6, 8, CYT b, ND 5, 6 and tRNAs. Based on the MITODAT database as a sequence reference, 25 of the 44 (57%) variants observed were unreported. Notably, a heteroplasmic variant C8515G/T in the MT-ATP 8 gene and a germline variant 8327delA in the tRNAlys was observed in all the tissue samples of the three adenomatous polyps in comparison to the referenced database sequence. A germline variant G9055A in the MT-ATP 6 gene had a frequency of 100% (17/17) in tubular and 57% (13/23) in villous adenomas; no corresponding variant was in tubulovillous adenomas. Furthermore, A9006G variant at MT-ATP 6 gene was observed at frequency of 57% (13/23) in villous adenomas only. Interestingly, variants A9006G and G9055A were absent in the villous tissue samples that were clinicopathological designated as "polyvillous adenomas". Our current data provide a basis for continued investigation of certain mtDNA variants as predictors of the three adenomatous polyps in a larger number of clinicopathological specimens.

Meta-analysis shows colon capsule endoscopy is effective in detecting colorectal polyps

BACKGROUND & AIMS

Colon capsule endoscopy (CCE) is a noninvasive and painless technique used to explore the colon without sedation or air insufflation. We performed a systematic review and meta-analysis to assess the accuracy of CCE in detecting colorectal polyps.

METHODS

The MEDLINE, EMBASE, and SCOPUS databases were searched, from 2006 to 2009, for the terms "colon capsule" and "Pillcam colon"; searches included abstracts. Studies were included that focused on detecting colorectal polyps with CCE and that were verified using within-subject reference colonoscopy. The risk of bias within each study was ascertained according to Quality Assessment of Diagnostic Accuracy in Systematic Reviews recommendations. The per-patient sensitivity and specificity were calculated for polyps of any size and for significant findings (polyps, > or =6 mm in size or >3 in number). Forest plots were produced based on random-effect models. The risk of bias across studies was assessed using the interstudy heterogeneity statistic, meta-regression, and the Egger test.

RESULTS

Eight studies provided data on 837 patients; the prevalences of polyps and significant findings were 57% and 27.4%, respectively. CCE sensitivity for polyps of any size and significant findings were 71% and 68%, respectively. CCE specificity for polyps of any size and significant findings were 75% and 82%, respectively. High levels of heterogeneity (interstudy heterogeneity, >75%) were not detected. Moderate heterogeneity partially was explained by the different design of individual studies. CCE identified 16 of the 21 cancerous lesions detected by colonoscopy (pooled sensitivity, 76%).

CONCLUSIONS

CCE sensitivity for polyps and significant findings compares favorably with other noninvasive colorectal cancer screening strategies. CCE specificity is likely to be underestimated because reference colonoscopy examination results are blinded.

Polyp size measurement at CT colonography: what do we know and what do we need to know?

Polyp size is a critical biomarker for clinical management. Larger polyps have a greater likelihood of being or of becoming an adenocarcinoma. To balance the referral rate for polypectomy against the risk of leaving potential cancers in situ, sizes of 6 and 10 mm are increasingly being discussed as critical thresholds for clinical decision making (immediate polypectomy versus polyp surveillance) and have been incorporated into the consensus CT Colonography Reporting and Data System (C-RADS). Polyp size measurement at optical colonoscopy, pathologic examination, and computed tomographic (CT) colonography has been studied extensively but the reported precision, accuracy, and relative sizes have been highly variable. Sizes measured at CT colonography tend to lie between those measured at optical colonoscopy and pathologic evaluation. The size measurements are subject to a variety of sources of error associated with image acquisition, display, and interpretation, such as partial volume averaging, two- versus three-dimensional displays, and observer variability. This review summarizes current best practices for polyp size measurement, describes the role of automated size measurement software, discusses how to manage the measurement uncertainties, and identifies areas requiring further research.

The plasminogen system in microdissected colonic mucosa distant from an isolated adenoma

In the colon, the urokinase-type plasminogen activator (uPA), its receptor (uPAR), and plasminogen activator inhibitors, PAI-1 and PAI-2, are implicated in the transition from mucosa to adenoma and tumour progression. However, expression in the mucosa adjacent, or distant, to an adenoma has not yet been investigated. Three biopsies from mucosae adjacent (20 cm, ipsilateral) and distant (contralateral) to an isolated tubular adenoma were analysed in 14 patients and 8 controls. Laser microdissection isolated stromal and epithelial crypt components, and quantitative RT-PCR analyses of uPA, uPAR, PAI-1 and PAI-2 mRNA levels were performed. Among controls, no significant differences in the markers were noted. With left colon isolated tubular adenoma, uPA, uPAR, and PAI-2 mRNA levels were significantly increased in the adjacent mucosal stroma compared to epithelial crypt levels (p < 0.05). In right colon adenoma, the mRNA levels of these 3 molecular markers were significantly increased only in the adjacent mucosal stromal samples (p < 0.05). Isolated tubular adenoma in the colon increases significantly the mRNA levels of 3 proteolysis-associated molecular markers in the stromal, but not in the epithelial, components of adjacent mucosa. These results suggest the presence of regional and dynamic interactions in apparently non-involved mucosae.

Nonlaxative PET/CT colonography: feasibility, acceptability, and pilot performance in patients at higher risk of colonic neoplasia

CT colonography without bowel preparation is a safer and better-tolerated alternative to full laxation protocols, but comparative sensitivity and specificity are potentially reduced. Uptake of (18)F-FDG by colonic neoplasia is well described, and combining PET with nonlaxative CT colonography could improve accuracy. The purpose was to prospectively test the technical feasibility and acceptability of combined nonlaxative PET/CT colonography in patients at higher risk of colorectal neoplasia and to provide pilot data on diagnostic performance.

METHODS

Fifty-six patients (median age, 64 y; 30 women) at high risk of colonic neoplasia underwent nonlaxative PET/CT colonography with barium fecal tagging within 2 wk of scheduled colonoscopy. Colonic segmental distension was graded 1 (poor) to 3 (good). A radiologist, experienced in CT colonography, and nuclear medicine physician in consensus analyzed the datasets. The diagnostic performance for standalone CT colonography and combined PET/CT colonography was compared with the reference colonoscopy. Patient experience for 25 items (each scored from 1 to 7) pertaining to satisfaction, worry, and physical discomfort was canvassed after both PET/CT colonography and colonoscopy.

RESULTS

Distension was good in 298 of 334 segments (89%; 95% confidence interval [CI], 85%-92%). Patients experienced more physical discomfort during colonoscopy (median, 4; interquartile range [IQR], 2-7) than during PET/CT colonography (median, 5; IQR, 3-7; P = 0.03) and were more willing to undergo PET/CT colonography again (36/43 [84%; 95% CI, 73%-95%] vs. 31/43 [72%; 95% CI, 59%-86%]; P = 0.001). Twenty-one patients had 54 polyps according to colonoscopy (10 with at least 1 polyp >or=6 mm and 8 with at least 1 polyp >or=10 mm). Of 14 polyps 6 mm or greater, 12 (86%; 95% CI, 67%-100%) were (18)F-FDG-avid, including all those 10 mm or greater (mean standardized uptake value, 10.1). CT colonography sensitivity for polyps 6 mm or larger was 92.9% (95% CI, 79.4%-100%) and was not improved by the addition of PET. However, combined PET/CT colonography review improved per-patient positive predictive value for a polyp 10 mm or greater from 73% (95% CI, 39-92) to 100% (95% CI, 60-100).

CONCLUSION

In this feasibility study, simultaneous PET acquisition during nonlaxative CT colonography is technically feasible, is well tolerated, and potentially improves specificity.

Clinicopathological features of colon polyps from African-Americans

BACKGROUND AND AIMS

Among the ethnic groups, the age-standardized incidence rate of colorectal cancer (CRC) is highest among African-Americans. The majority of CRC arise from preexisting adenoma. It is shown that 30% of the US adult population has adenomas. The potential risk of malignant transformation in adenomas differs by specific pathologic and clinical characteristics that we aimed to study in AAs.

MATERIALS AND METHODS

All pathologic reports (150,000) in Howard University Hospital from 1959 to 2006 were reviewed manually. Those pathology reports compatible with the colorectal polyps were carefully reviewed and selected by a GI pathologist. All cases with cancer were then excluded from the list. Data were then entered into Microsoft Excel and checked for missing data and duplications. Differences in right-side and left-side polyps for sex, histology, and clinical symptoms were assessed by Chi-2 test.

RESULTS

A total number of 5,013 colorectal polyps were diagnosed in this period that include 47% male, with mean age (SD) of 63 (12). Half of the cases were diagnosed in 2001-2006. Tubular adenoma was the most frequent pathology (73%). The highest frequency of right-sided polyps was observed in the 1990s (56%). Left-sided polyps were younger (p < 0.0001), more hyperplasic (23 vs. 5%; p < 0.0001), and more frequent in female (56 vs. 52%; p = 0.02) compared to right-sided polyps. The frequency of right-sided adenoma significantly increases from 18% in the 1960s to 51% in the period of 2001-2006 (p < 0.0001). The most frequent symptom in both sides was GI bleeding (21%).

CONCLUSION

There was a ratio of 8:1 for neoplastic to hyperplastic polyps in our study, which is more than what has been reported in Caucasians (7:1). Our data shows a shift in polyps from the left side to the right side of the colon in recent years. This data is consistent with the lack of a reduction in the incidence of colon cancer in African-Americans. Screening is thus very important in AA to reduce the incidence of colon cancer.

Prevalence of nonpolypoid colorectal neoplasms in symptomatic patients scheduled for colonoscopy: a study with total colonic chromoscopy

OBJECTIVES

(i) To determine the prevalence of nonpolypoid colorectal neoplasms (NP-CRNs) in a prospective cohort of patients of a Mediterranean area; (ii) to compare the characteristics of NP-CRNs with those of polypoid adenomas, focusing on the rate of high-grade dysplasia (HGD) and carcinoma; (iii) to evaluate the characteristics of patients harboring NP-CRNs versus patients with protruding adenomas (P-CRNs).

PATIENTS AND METHODS

A prospective, cross-sectional observational study was made in which consecutive unselected patients were scheduled for colonoscopy and pancolonic chromoendoscopy. The Paris Classification of Superficial Neoplastic Lesions was used to classify the detected lesions, and the revised Vienna criteria were applied to describe the grade of dysplasia. All examinations were performed by the same endoscopist, and all samples were reviewed by the same pathologist.

RESULTS

A total of 290 patients were included, and 613 neoplasms were detected-26% of them being NP-CRNs. The prevalence of NP-CRNs was 34.1% [95% confidence interval (CI): 28.8%-39.7%]. The proportion of HGD or carcinoma in NP-CRNs was 2.5% (95% CI: 0.8%-5.9%), versus 2.9% in P-CRNs (95% CI: 1.6%-4.7%). Size larger than 10 mm [odds ratio: 22.7 (95% CI: 5.2-99.2)] and a pedunculated morphology [odds ratio: 5.7 (95% CI: 1.3-24.3)] were related to the presence of HGD or carcinoma. A relationship between increased size and HGD or carcinoma was found for all morphologies. Patients harboring only NP-CRNs and patients harboring only P-CRNs were similar for all the variables collected.

CONCLUSIONS

NP-CRNs have a high prevalence in our region, but show a proportion of HGD and carcinoma similar to that seen in P-CRNs. No patient variable is predictive of the presence of a NP-CRN.

Debate: diminutive polyps noted at CT colonography need not be reported

Colorectal polyps less than 6 mm in size pose a negligible risk to the development of colorectal carcinoma. The sensitivity and specificity for detection of diminutive lesions on all available examinations including CT colonography (CTC) and optical colonoscopy (OC) is relatively low. In the context of regular screening, the low clinical significance and slow to negligible growth of diminutive polyps, as well as the low detection performance of CTC and OC for these lesions, would contribute to wasted health care resource and excess morbidity if each diminutive polyp were referred for potential resection. Respect for patient safety, attention to proper use of resources, and appropriate focus on larger, clinically significant polyps lead the authors to the conclusion that colonic polyps of less than 6 mm should not be separately reported.

Yield of high-grade dysplasia based on polyp size detected at colonoscopy: a series of 2295 examinations following a positive fecal occult blood test in a population-based study

PURPOSE

The aim was to determine the rate of high-grade dysplasia among patients with all adenomas, and its prevalence in patients with adenomas of different sizes in a well-defined population-based study.

POPULATION AND METHODS

We performed a secondary analysis of the 2295 colonoscopies performed following a positive fecal occult blood test result during the first round of colorectal cancer screening in one French district. The rates of high-grade dysplasia were calculated for 3 size categories of adenoma (diminutive, <or=5 mm; small, 6-9 mm; large, >or=10 mm). Predictive factors for high-grade dysplasia were assessed by univariate and multivariate analyses.

RESULTS

A total of 1284 adenomas were detected in 784 subjects. High-grade dysplasia was present in 32.1% of the 784 subjects and in 2.7%, 16.0%, and 51.1% of those whose adenomas were diminutive, small, and large, respectively. Among subjects with no more than 2 small adenomas, the proportion of those with high-grade dysplasia was 12.4%. Both adenoma size and a villous component within adenomas were found to be independent predictive factors for high-grade dysplasia by multivariate analysis.

CONCLUSIONS

Because of the high rate of high-grade dysplasia among small adenomas, our results reinforce the need to remove all small adenomas detected at colonoscopy. Furthermore, the results suggest that opting for CT colonography surveillance instead of colonoscopic removal among subjects with one or 2 small polyps revealed by CT colonography would have led to missed high-grade dysplasia in 12.4% of them.

Polyp measurement based on CT colonography and colonoscopy: variability and systematic differences

Objective

To assess the variability and systematic differences in polyp measurements on optical colonoscopy and CT colonography.

Materials

Gastroenterologists measured 51 polyps by visual estimation, forceps comparison and linear probe. CT colonography observers randomly assessed polyp size two-dimensionally (abdominal and intermediate window) and three-dimensionally (manually and semi-automatically). Linear mixed models were used to assess the variability and systematic differences between CT colonography and optical colonoscopy techniques.

Results

The variability of forceps and linear probe measurements was comparable and both showed less variability than measurement by visual assessment. Measurements by linear probe were 0.7 mm smaller than measurements by visual assessment or by forceps. The variability of all CT colonography techniques was lower than for measurements by forceps or visual assessment and sometimes lower (only 2D intermediate window and manual 3D) compared with measurements by linear probe. All CT colonography measurements judged polyps to be larger than optical colonoscopy, with differences ranging from 0.7 to 2.3 mm.

Conclusion

A linear probe does not reduce the measurement variability of endoscopists compared with the forceps. Measurement differences between observers on CT colonography were usually smaller than at optical colonoscopy. Polyps appeared larger when using various CT colonography techniques than when measured during optical colonoscopy.

Colorectal cancer screening

Colorectal cancer (CRC) constitutes the second leading cause of death from cancer in the United States. Increased screening for CRC have been associated with a decreased incidence in the past two decades. Continued efforts are necessary to maintain this trend. Appropriate risk stratification of individuals and compliance with recommended screening strategies are important. Colonoscopy continues to play an important role in screening; however, several different screening options are available for average-risk individuals. This article reviews the current options open to physicians to adequately screen patients for CRC based on inherit risks.

Variation in detection of adenomas and polyps by colonoscopy and change over time with a performance improvement program

BACKGROUND & AIMS

There has been no prospective, community-based study to track changes in adenoma detection by individual physicians over time and to determine the effectiveness of targeted educational interventions.

METHODS

We prospectively collected information on 47,253 screening colonoscopies in average-risk individuals 50 years and older performed by a community-based practice in the Twin Cities of Minnesota. During a period of 3 years, 5 specific interventions were implemented; each was designed to improve adenoma detection rates. Controlling for patient-related and procedure-related factors, rates of adenoma detection and 3-year trends for individual physicians were plotted, and intraclass correlation coefficients were calculated. Generalized estimating equations were used to identify factors associated with detection of adenomas and polyps.

RESULTS

At least 1 polyp and 1 adenoma were found in 36% and 22% of examinations, respectively. Adenoma detection rates by endoscopists ranged from 10%-39%. There was no significant improvement during the study period despite planned, systematic interventions. Factors associated with adenoma detection included age of the patient (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.02-1.02), male sex (OR, 1.53; 95% CI, 1.34-1.74), and adequate preparation quality (OR, 2.26; 95% CI, 1.64-3.12).

CONCLUSIONS

The detection of adenomas by individual physicians during a 3-year period varied and did not appear to change between individual endoscopists, despite planned, systematic interventions. This indicates that other targeted interventions might be required to improve adenoma detection rates among experienced, community gastroenterologists.

Characteristics of metachronous colorectal adenomas found during long-term follow-up: analysis of four subsequent generations of adenoma recurrence

OBJECTIVE

Because of the high recurrence rates of colorectal adenomas, regular surveillance by colonoscopy has been recommended, but there is still a dearth of information on the long-term results of follow-up colonoscopy after polypectomy. The aims of this study were to determine the differences between initial adenomas and metachronous lesions, to evaluate the effect of long-term surveillance and to describe the hypothetical origin of the colorectal adenoma-carcinoma sequence.

MATERIAL AND METHODS

Between 1978 and 2003 a total of 1091 patients undergoing periodic surveillance examinations were prospectively documented at the Erlangen Registry of Colorectal Polyps. Differences between initial and metachronous lesions found during long-term follow-up were studied. Statistical analysis using chi(2) testing of adenoma characteristics found in four subsequent recurrence periods was carried out, and the relative risk (RR) for the development of metachronous adenomas of advanced pathology was calculated.

RESULTS

In comparison with the initial findings, metachronous adenomas are generally significantly smaller lesions (p<0.00001), usually tubular in shape (p<0.00001) and bearing high-grade dysplasia less often (p<0.00001) and are usually located in the right colon (p<0.00001). These differences are found between the initial and four subsequent generations of metachronous adenomas. The number of synchronous adenomas is reduced only in the first recurrence (p<0.001); in the further generations equal proportions of multiplicity are found, as in the baseline examination. Patients with adenomas of advanced pathology, i.e. large, tubulovillous or villous adenomas at baseline, have a significantly higher risk for large (RR 2.73; 95% CI 1.77-4.20), tubulovillous or villous (RR 1.55; 95% CI 1.06-2.25) or multiple (RR 2.45; 95% CI 1.83-3.29) metachronous adenomas at the first recurrence.

CONCLUSIONS

Metachronous adenomas show the uniform characteristics of being small tubular lesions rarely bearing high-grade dysplasia, usually located in the right colon. Thus regular follow-up colonoscopy can provide sufficient colorectal carcinoma prevention.

[Evaluation of computed tomographic colonography for detection of colorectal polyps]

BACKGROUND

Computed tomographic colonography has been proposed for detection of colorectal polyps instead of colonoscopy in colorectal cancer screening programs.

AIM

To evaluate the performance of computed tomographic colonography in the detection of colorectal polyps with colonoscopy used as the gold standard.

METHODS

We prospectively studied 20 patients at high risk for colorectal neoplasia (14 men and 6 women; mean age, 55 years and 59 years). Computed tomographic colonography was performed immediately before colonoscopy. We inserted a rectal balloon catheter and insufflated the colon with room air to the level that a good distension was observed. Twenty milligrams of hioscin was given immediately before computed tomographic imaging of the abdomen and pelvis in order to minimize the degree of smooth-muscle spasm and peristalsis and to reduce the patient's discomfort.

RESULTS

Computed tomographic colonography images were considered satisfactory in all cases. Colonoscopy detected 85 polyps in 19 of 20 patients (95%). All the observed polyps were successfully removed and examined histologically. The radiological examination correctly identified 8 of 10 polyps 10 mm or more in diameter, 2 of 19 (18,2%) with 5-9 mm, and just 1 of 53 <5mm (9,1%). Seventeen of the 43 adenomatous polyps were > or =5 mm. Eight (47%) were correctly identified on computed tomographic colonography. None of the neoplasias <5 mm were identified on colonography. Nineteen patients preferred colonoscopy in the event of having to repeat on of the two examinations.

CONCLUSION

For the detection of colorectal polyps, computed tomographic colonography seems to be useful only when the result is positive, as the negative results of this examination cannot eliminate the presence of these lesions.

Capsule endoscopy versus colonoscopy for the detection of polyps and cancer

BACKGROUND

An ingestible capsule consisting of an endoscope equipped with a video camera at both ends was designed to explore the colon. This study compared capsule endoscopy with optical colonoscopy for the detection of colorectal polyps and cancer.

METHODS

We performed a prospective, multicenter study comparing capsule endoscopy with optical colonoscopy (the standard for comparison) in a cohort of patients with known or suspected colonic disease for the detection of colorectal polyps or cancer. Patients underwent an adapted colon preparation, and colon cleanliness was graded from poor to excellent. We computed the sensitivity and specificity of capsule endoscopy for polyps, advanced adenoma, and cancer.

RESULTS

A total of 328 patients (mean age, 58.6 years) were included in the study. The capsule was excreted within 10 hours after ingestion and before the end of the lifetime of the battery in 92.8% of the patients. The sensitivity and specificity of capsule endoscopy for detecting polyps that were 6 mm in size or bigger were 64% (95% confidence interval [CI], 59 to 72) and 84% (95% CI, 81 to 87), respectively, and for detecting advanced adenoma, the sensitivity and specificity were 73% (95% CI, 61 to 83) and 79% (95% CI, 77 to 81), respectively. Of 19 cancers detected by colonoscopy, 14 were detected by capsule endoscopy (sensitivity, 74%; 95% CI, 52 to 88). For all lesions, the sensitivity of capsule endoscopy was higher in patients with good or excellent colon cleanliness than in those with fair or poor colon cleanliness. Mild-to-moderate adverse events were reported in 26 patients (7.9%) and were mostly related to the colon preparation.

CONCLUSIONS

The use of capsule endoscopy of the colon allows visualization of the colonic mucosa in most patients, but its sensitivity for detecting colonic lesions is low as compared with the use of optical colonoscopy. (ClinicalTrials.gov number, NCT00604162.)

Colorectal cancer screening with CT colonography: key concepts regarding polyp prevalence, size, histology, morphology, and natural history

OBJECTIVE

The purpose of this article is to provide a timely update on a variety of key polyp topics to construct a proper framework for physicians who are interested in providing CT colonography screening as a clinical service.

CONCLUSION

As the medical community considers the expansion of CT colonography for screening, we believe it is prudent to update and review several key concepts regarding colorectal polyps. In particular, it is important to replace the older literature derived from high-risk and symptomatic cohorts with the wealth of newer and more applicable data from average-risk and asymptomatic screening cohorts. Familiarity with current concepts regarding flat (nonpolypoid) lesions and the natural history of small colorectal polyps is also vital to the effective application of this technique.

Management of small polyps detected by screening CT colonography: patient and physician preferences

BACKGROUND

Management of small polyps found on computed tomography (CT) colonography is controversial and critical to both cancer outcomes and cost. Patient and physician behavior are influenced by personal beliefs and prior experience. Thus, we aimed to understand patient and physician preferences after finding polyps on CT colonography.

METHODS

Patients were given a validated handout and survey asking for their preference for evaluation of a "pea-sized" polyp found on CT colonography. By using an Internet survey, physicians were asked how they would manage a 5-mm, 8-mm, or 12-mm polyp, or three 5-mm polyps found by CT colonography in a hypothetical 52-year-old patient of average colorectal cancer risk. Survey reliability was assessed using Cronbach's coefficient alpha.

RESULTS

Of the 305 patient respondents, 95% wanted to know if the polyp found on CT colonography was precancerous, 86% stated they would request endoscopic evaluation, and 85% wanted polypectomy. Of the 277 primary care physicians, 71% would refer a 5-mm sigmoid polyp for endoscopy, 86% would refer an 8-mm polyp, 97% would refer a 12-mm polyp, and 91% would refer three 5-mm polyps. Of the 461 gastroenterologists, 83% would refer a 5-mm sigmoid polyp for endoscopy, 96% would refer an 8-mm polyp, 97% would refer a 12-mm polyp, and 93% would refer three 5-mm polyps. Overall, 75% of physicians indicated the fear of missing a precancerous lesion would prompt referral for colonoscopy.

CONCLUSION

Both patients and physicians overwhelmingly preferred to follow up small polyps identified by CT colonography with endoscopy, suggesting that population-based CT colonography screening programs in which polyps are not removed might require significant patient and physician education before implementation.

Genetic polymorphisms in the cyclooxygenase-1 and cyclooxygenase-2 genes and risk of colorectal adenoma

PURPOSE

Cyclooxygenase (COX) enzymes, COX1 and COX2, are key in converting arachidonic acid (AA) into prostaglandins that have been associated with colorectal carcinogenesis. The aim of our study was to investigate associations of polymorphisms in COX genes, alone and in interaction with exposures known to be related to inflammation and AA metabolism, with risk of colorectal adenomas.

MATERIALS AND METHODS

In a community-, colonoscopy-based case-control study with 162 incident, sporadic colorectal adenoma cases and 211 controls, we investigated associations of two promoter polymorphisms (-842 A > G in COX1 and -765 G > C in COX2) and two polymorphisms in the 3'-UTR of COX2 (8473 T > C and 9850 A > G) with risk of adenomas. Multiple logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) of colorectal adenoma after adjusting for potential confounders.

RESULTS

Overall, there was no evidence for an association between any of the four polymorphisms and colorectal adenomas. However, we found a statistically significant interaction between the COX2 8473 T > C polymorphism and nonsteroidal anti-inflammatory drug (NSAIDs) use (P (interaction) = 0.03): The greatest reduced risk was observed for individuals with the 8473 C variant allele who also regularly used NSAIDs (OR = 0.35, 95% CI 0.16-0.75).

CONCLUSION

These results suggest that the C allele of COX2 8473 T > C polymorphism may interact with NSAIDs to reduce risk for colorectal adenoma.

Identification of colorectal adenomas by a quantitative immunochemical faecal occult blood screening test depends on adenoma characteristics, development threshold used and number of tests performed

BACKGROUND

Faecal occult blood tests (FOBT) are faulted by low sensitivity for advanced adenomatous polyps (AAP). Quantified, immunochemical, haemoglobin (Hb)-specific immunochemical FOBT (I-FOBT) measurements are now used for colorectal screening.

AIMS

To correlate adenoma characteristics to amount of faecal Hb lost and to evaluate sensitivity and specificity for AAP by faecal Hb development threshold used and number of I-FOBTs collected.

METHODS

Three daily I-FOBTs were collected and analysed in 1221 patients scheduled for colonoscopy. Faecal Hb was analysed as ngHb/mL of buffer and the highest result related to colonoscopy findings.

RESULTS

In 1204 patients without cancer, colonoscopy identified adenomas in 294, 99 with AAPs. Adenoma patients had elevated faecal Hb increasing with advanced histology, size, pedunculated shape and multiplicity (P < 0.001 for all). At 50 ngHb/mL threshold, sensitivity and specificity for AAPs were 54.5% (95%CI 44.7, 64.7) and 88.1% (95%CI 86.2, 90.1) for three tests. At higher thresholds, sensitivity decreased, but was significantly higher with more samples collected. Conversely, specificity increased at higher thresholds, but decreased with more samples.

CONCLUSIONS

Faecal Hb loss from adenomas is significantly associated with size, number and advanced features. Sensitivity and specificity for AAPs are determined by test threshold chosen and number of samples collected; these determine the number of colonoscopies needed for positive tests.

Effect of clinicopathologic factors on visibility of colorectal polyps with FDG PET

OBJECTIVE

The objective of our study was to clarify which clinicopathologic factors affect the FDG PET visibility of colorectal polyps.

MATERIALS AND METHODS

We used statistical methods in a retrospective examination of factors affecting the visibility of 87 colorectal polyps in 50 patients who underwent PET for cancer screening.

RESULTS

PET depicted 37% (32/87) of polyps. Univariate analysis revealed significant associations between polyp visibility and polyp size, histologic grade (p < 0.001 each), type (p = 0.004), and patient age (p = 0.049) but not sex or polyp location. The visualization rate increased with increases in polyp size (< or = 5 mm, 12%; 6-10 mm, 47%; > or = 11 mm, 59%) and severity of dysplasia (indefinite or low-grade dysplasia, 13%; high-grade dysplasia, 67%; polyp with early carcinoma, 75%) and was higher for pedunculated polyps (59%) than for nonpedunculated polyps (27%). Multivariate analysis showed that histologic grade was the strongest factor (p < 0.001) among three independent factors (histologic grade, type, and age). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for visualization of high-grade or early carcinoma polyps to be removed were 71%, 87%, 78%, 82%, and 80%. Maximum standardized uptake values did not differ significantly between visualized polyps with indefinite or low-grade dysplasia and visualized polyps with high-grade dysplasia or early carcinoma.

CONCLUSION

Histologic grade is the strongest independent factor in FDG PET visibility of colorectal polyps. FDG PET visibility may be helpful for predicting whether a polyp should be removed or observed. FDG PET findings also may suggest the need to alter the treatment of patients with colorectal polyps.

Effect of institution-wide policy of colonoscopy withdrawal time > or = 7 minutes on polyp detection

BACKGROUND & AIMS

Practice guidelines recommend that endoscopists spend at least 7 minutes examining the colonic mucosa during colonoscopy withdrawal to optimize polyp yield. The aim of this study was to determine if the implementation of an institution-wide policy of colonoscopy withdrawal time > or = 7 minutes was associated with an increase in colon polyp detection.

METHODS

All 42 endoscopists at our institute were asked to attain a colonoscopy withdrawal time of at least 7 minutes. Compliance with 7-minute withdrawal time was recorded for all nontherapeutic colonoscopies. Polyp detection ratio (number of polyps detected divided by number of colonoscopies performed) was computed. Regression models were used to assess the association between compliance with 7-minute withdrawal time and polyp detection.

RESULTS

During the study period, 23,910 colonoscopies were performed. The average age of patients was 56.8 years, and 54% were female. Colon cancer screening or surveillance was the indication for 42.5% of colonoscopies. At the beginning of the study, the polyp detection ratio was 0.48. Compliance with 7-minute withdrawal time for nontherapeutic procedures increased from 65% at the beginning of the initiative to almost 100%. However, no increase in polyp detection ratio was noted over the same period for all polyps (slope, 0.0006; P = .45) or for polyps 1-5 mm (slope, 0.001; P = .26), 6-9 mm (slope, 0.002; P = .43), or > or = 10 mm (slope, 0.006; P = .13). No association was detected when only colonoscopies performed for screening or surveillance were analyzed.

CONCLUSIONS

An institution-wide policy of colonoscopy withdrawal time > or = 7 minutes had no effect on colon polyp detection.

Chromoendoscopy detects more adenomas than colonoscopy using intensive inspection without dye spraying

Conventional colonoscopy misses some neoplastic lesions. We compared the sensitivity of chromoendoscopy and colonoscopy with intensive inspection for detecting adenomatous polyps missed by conventional colonoscopy. Fifty subjects with a history of colorectal cancer or adenomas underwent tandem colonoscopies at one of five centers of the Great Lakes New England Clinical Epidemiology and Validation Center of the Early Detection Research Network. The first exam was a conventional colonoscopy with removal of all visualized polyps. The second exam was randomly assigned as either pan-colonic indigocarmine chromoendoscopy or standard colonoscopy with intensive inspection lasting >20 minutes. Size, histology, and numbers of polyps detected on each exam were recorded. Twenty-seven subjects were randomized to a second exam with chromoendoscopy and 23 underwent intensive inspection. Forty adenomas were identified on the first standard colonoscopies. The second colonoscopies detected 24 additional adenomas: 19 were found using chromoendoscopy and 5 were found using intensive inspection. Chromoendoscopy found additional adenomas in more subjects than did intensive inspection (44% versus 17%) and identified significantly more missed adenomas per subject (0.7 versus 0.2, P < 0.01). Adenomas detected with chromoendoscopy were significantly smaller (mean size 2.66 +/- 0.97 mm) and were more often right-sided. Chromoendoscopy was associated with more normal tissue biopsies and longer procedure times than intensive inspection. After controlling for procedure time, chromoendoscopy detected more adenomas and hyperplastic polyps compared with colonoscopy using intensive inspection alone. Chromoendoscopy detected more polyps missed by standard colonoscopy than did intensive inspection. The clinical significance of these small missed lesions warrants further study.

Risk of advanced metachronous colorectal adenoma during long-term follow-up

BACKGROUND

According to the adenoma-carcinoma concept, all colorectal adenomas are to be removed and all patients have to undergo regular surveillance examinations. But there is still shortage on information on the long-term results of follow-up colonoscopy after polypectomy.

METHODS

Between 1978 and 2003, more than 20,000 polyps were prospectively documented at the Erlangen Registry of Colorectal Polyps. A total of 1,091 patients undergoing periodic surveillance examinations are studied for differences between initial and metachronous lesions of the colorectum. Statistical analysis using chi (2)-testing of adenoma characteristics found in four subsequent recurrence periods and calculation of the relative risk (RR) for the development of metachronous adenomas of advanced pathology was performed.

RESULTS

In comparison with the initial findings, metachronous adenomas are, in general, significantly smaller ones (p < 0.00001), more frequently tubular lesions (p < 0.00001) and bearing less often high-grade dysplasia (p < 0.00001). Adenomas of advanced pathology were significantly less often found during follow-up than at baseline examination (p < 0.0001). These differences are found between the initial and four subsequent generations of metachronous adenomas. Patients with adenomas of advanced pathology at baseline have a significantly higher risk for metachronous adenomas of advanced pathology (RR 1.51; 95%CI 1.04-1.93) at the first recurrence.

CONCLUSIONS

Metachronous adenomas show uniform characteristics of being small tubular lesions rarely bearing high-grade dysplasia. Thus, regular surveillance examinations can provide sufficient colorectal carcinoma prevention.

Effect of a time-dependent colonoscopic withdrawal protocol on adenoma detection during screening colonoscopy

BACKGROUND & AIMS

Screening colonoscopy can prevent cancer by removal of adenomatous polyps. Recent evidence suggests that insufficient time for inspection during overly rapid colonoscope withdrawal may compromise adenoma detection. We conducted a study of the effect of a minimum prespecified time for instrument withdrawal and careful inspection on adenoma detection rates during screening colonoscopy.

METHODS

Baseline data consisted of neoplasia detection rates during 2053 screening colonoscopies performed without a specified withdrawal protocol. During a subsequent 13-month period we performed 2325 screening colonoscopies using dedicated inspection techniques and a minimum 8-minute withdrawal time. With colonoscopists comprising the study population, we compared overall and individual rates of neoplasia detection in postintervention procedures with those in baseline examinations.

RESULTS

As compared with baseline subjects, postintervention subjects had higher rates of any neoplasia (34.7% vs 23.5%, P < .0001) and of advanced neoplastic lesions per patient screened (0.080 +/- 0.358 vs 0.055 +/- 0.241, P < .01). Twenty-five percent of advanced neoplastic lesions detected in postintervention examinations were 9 mm or less in diameter, versus 10% in baseline examinations (P < .001). Endoscopists with mean withdrawal times of 8 minutes or longer had higher rates of detection of any neoplasia (37.8% vs 23.3%, P < .0001) and of advanced neoplasia (6.6% vs 4.5%, P = .13) compared with those with mean withdrawal times of less than 8 minutes.

CONCLUSIONS

After implementing a protocol of careful inspection during a minimum of 8 minutes to withdraw the colonoscope, we observed significantly greater rates of overall and advanced neoplasia detection during screening colonoscopy.

Identification of patients at increased risk for colorectal cancer in an open access endoscopy center

GOALS

To determine whether patients referred for open access endoscopy (OAE) are being appropriately identified as "increased risk" or "average risk" for colorectal cancer (CRC) by referring physicians.

BACKGROUND

OAE allows nongastroenterologists to schedule elective endoscopies without prior consultation with a gastroenterologist. It is unknown how accurately referring physicians identify CRC risk of such patients.

METHODS

We retrospectively reviewed the records of outpatients referred to a single OAE center for screening or surveillance colonoscopy from July 1, 2001 to November 8, 2002. Before colonoscopy, a 3-question tool was used to stratify each patient as average risk or increased risk for CRC. CRC risk assessment was compared with the referring physician's indication for colonoscopy. Chi-square testing was used to compare the incidence of neoplastic polyps between average risk and increased risk patients.

RESULTS

Two hundred eighty-eight patients met inclusion criteria. Referring physicians accurately identified 61% of 126 increased risk patients, including 13 of 19 patients (68%) with a personal history of CRC, 29 of 61 patients (48%) with a family history of CRC, 47 of 61 patients (77%) with a personal history of colonic polyps, and 0 of 8 patients (0%) who met clinical criteria for hereditary nonpolyposis colorectal cancer. Adenomatous polyps were found in 24% of average risk patients compared with 41% of increased risk patients (P<0.01).

CONCLUSIONS

In an OAE system, referring physicians often fail to correctly identify patients at increased risk for CRC. Our 3-question tool for risk assessment helps to better identify patients at increased risk of CRC and can be used by gastroenterologists to stratify patients referred for OAE.

Polyp size and advanced histology in patients undergoing colonoscopy screening: implications for CT colonography

BACKGROUND & AIMS

Colorectal cancer screening with diagnostic imaging can detect polyps. The management of patients whose largest polyp is less than 10 mm is uncertain. The primary aim of this study was to determine rates of advanced histology in patients undergoing colorectal cancer screening whose largest polyp is 9 mm or less.

METHODS

Subjects include all asymptomatic adults receiving colonoscopy for screening during 2005 from 17 practice sites, which provide both colonoscopy and pathology reports to the Clinical Outcomes Research Initiative repository. Patients were classified by size of largest polyp. Advanced histology was defined as an adenoma with villous or serrated histology, high-grade dysplasia, or an invasive cancer. Risk factors for advanced histology were determined using Pearson chi(2) and Fisher exact tests.

RESULTS

Among 13,992 asymptomatic patients who had screening colonoscopy, 6360 patients (45%) had polyps, with complete histology available in 5977 (94%) patients. The proportion with advanced histology was 1.7% in the 1- to 5-mm group, 6.6% in the 6- to 9-mm group, 30.6% in the greater than 10-mm group, and 72.1% in the tumor group. Distal location was associated with advanced histology in the 6- to 9-mm group (P = .04) and in the greater than 10-mm group (P = .002).

CONCLUSIONS

One in 15 asymptomatic patients whose largest polyp is 6 to 9 mm will have advanced histology and would undergo surveillance at 3 years based on current guidelines. Because histology is necessary for this decision, most of these patients should be offered colonoscopy. Further study should determine whether patients whose largest polyp is 1-5 mm can be safely followed without polypectomy.