The National Polyp Study

Pooled analysis of genetic variation at chromosome 8q24 and colorectal neoplasia risk

Several different genetic variants at chromosome 8q24 have been related to prostate, breast and colorectal cancer risk with evidence of region-specific risk differentials for various tumor types. We investigated the association between 15 polymorphisms located in 8q24 regions associated with cancer risk in a pooled analysis of 2587 colorectal adenoma cases, 547 colorectal cancer cases and 2798 controls of European descent from four studies. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for the associations. Three polymorphisms (rs10808555, rs6983267 and rs7837328) located between 128.47 and 128.54 Mb were found to be associated with colorectal tumor risk. The association was strongest for the previously reported rs6983267 variant and was similar for both adenoma (OR(per allele) = 1.16, 95% CI: 1.07-1.25, P = 0.0002) and cancer (OR (per allele) = 1.17, 95% CI: 1.01-1.35, P = 0.03). The strength of the association of the regional haplotype containing variant alleles at rs10808555, rs6983267 and rs7837328 but not rs10505476 was greater than that of any single variant of both adenoma (OR = 1.27, P = 0.0001) and cancer (OR = 1.26, P = 0.03). The risk associated with rs6983267 was stronger for multiple adenomas (OR(per allele) = 1.29, P = 5.6 x 10(-6)) than for single adenoma (OR(per allele) = 1.10, P = 0.03) with P(heterogeneity) = 0.008. This study confirms the association between colorectal neoplasia and the 8q24 polymorphisms located between 128.47 and 128.54 Mb and suggests a role for these variants in the formation of multiple adenomas.

Significant colonic neoplasia prevalence and ASGE recommendations: is it time for a change?

GOALS AND BACKGROUND

To Evaluate the indications versus diagnostic yield of significant colonic neoplasia (SCN) in the open-access era and screening colonoscopy.

STUDY

During 6-year period, all procedural data were obtained from all consecutive patients who underwent colonoscopies. Indications were compared with American Society for Gastrointestinal Endoscopy guidelines.

RESULTS

In all 22,341 procedures were included in the study. Indications were divided into 3 groups: Screening (21.89% of the procedures), surveillance (17.60%) and symptoms/signs (60.51%). A total of 2867 patients (12.83%) had SCNs. Of these, 278 (7.00%) SCNs were found in the group less than 50 years of age and 2589 in the group over the age of 50 years (14.10%). SCN as per indication frequency was 12.69% in the symptom/sign group (subdivided to 7.24% and 14.01% in the under 50 and over 50, age groups, respectively); screening 13.37% (5.48% and 15.09%, respectively); surveillance 12.64% (8.48% and 13.19%, respectively). The indications leading to the highest SCN rate (over 25%) were: abnormal imaging, elevated carcinoembryonic antigen, and rectal pain.

CONCLUSIONS

Colonoscopy is a unique screening tool that can detect neoplastic lesions. SCN prevalence in our study was between 13% and 15% for all indications in patients above 50 years of age. This emphasizes performing a screening colonoscopy for the entire population over the age of 50 years, regardless of the indication. We feel that American Society for Gastrointestinal Endoscopy guidelines should be reassessed. The revised criteria should state that the primary indication, are all people over the age of 50 years, who should have a colonoscopy performed, unless otherwise contraindicated.

Diverticulosis and colorectal cancer: between lights and shadows

The prevalence of diverticulosis and colorectal cancer (CRC) is markedly increased in the last century. Both diseases are highly frequent in Western countries and in aged people. Western diet--low in fiber and rich in dietary fat--has been largely regarded to play a major role in the pathogenesis of both conditions. A causal relationship between diverticulosis and CRC has been suggested in different studies. Epidemiologic series found a more frequent rectosigmoid localization of neoplastic lesions (advanced adenoma and CRC) in patients with diverticulosis as compared with controls, particularly in those with a previous diverticulitis episode or with an extensive disease. However, data are still controversial, with other studies failing to confirm this observation. Such discrepancy could be referred to the highly heterogeneous study design and setting in the different epidemiologic series. Pathologic studies showed that either macroscopic and microscopic chronic inflammation--which is regarded as risk factor for CRC development--is present in the colonic mucosa of some patients with diverticula. Moreover, alterations in the extracellular matrix, also involved in colorectal carcinogenesis, have been depicted in diverticulosis. In addition, an upward shifting of cell proliferation occurs in diverticular mucosa, and in nondiverticular patients with advanced adenomas. Finally, aberrant crypt foci--which are considered potential markers of CRC risk in ulcerative colitis--have been detected in colonic mucosa of patients with diverticulosis. Despite this substantial amount of evidence, however, the available data are not yet strong enough to suggest a more aggressive CRC prevention in diverticular as compared with nondiverticular subjects.

A summary measure of pro- and anti-oxidant exposures and risk of incident, sporadic, colorectal adenomas

Despite compelling basic science evidence, the search for causal associations linking specific pro- and anti-oxidants to presumably oxidative stress-related neoplasms, such as colorectal adenoma, has produced inconsistent results. We developed an oxidative balance score (OBS) to characterize the pro-oxidant and anti-oxidant exposures of 2,305 participants in a case-control study of colorectal adenoma that used both endoscopy-confirmed and community controls. Twelve lifestyle medical and dietary factors with known pro- or anti-oxidant properties were considered. Each high anti-oxidant exposure and low pro-oxidant exposure was awarded one or two points depending on the level of exposure, and the points for each OBS component were summed. We observed a significant inverse association between OBS (continuous variable) and colorectal adenoma in the analyses with either community, or endoscopy controls (each p-trend < 0.01). When the OBS was treated as an ordinal variable and a score of <or=3 points was used as the referent category, in the analyses with the endoscopy controls the adjusted odds ratios for scores of 4-6, 7-9, 10-12, 13-15, and 16+, were 0.42, 0.32, 0.22, 0.20, and 0.19, respectively, with all 95% confidence intervals excluding 1.0. The corresponding analysis for community controls showed a similar trend. Our findings are in line with the basic science evidence supporting the role of oxidative stress in colorectal neoplasia.

Epidemiology and quality control of 245 000 outpatient colonoscopies

INTRODUCTION

Screening colonoscopy is an effective means for early detection of colorectal carcinoma. Any exhaustive evaluation of the method must take further factors into account: epidemiology of colorectal adenomas and carcinomas in the target population, acceptance by the patients, structure, process, and outcome quality, and health economics.

METHODS

The internet-based colonoscopy database of the Bavarian Association of Statutory Health Insurance Physicians (ASHIP) for the year 2006 includes data on 86.05% of all outpatient colonoscopies performed in Bavarian ASHIP patients, or a total of 245 263 documented examinations.

RESULTS

The rate of participation in preventive colonoscopies was low (1.5%) and showed considerable geographical variation. The rate of detection of histologically confirmed colorectal neoplasia in symptom-free screened individuals was almost 26.0%. Some 1.3% of those screened had colorectal carcinoma. In 76.31% of the participants a completely clean gut was achieved. The incidence of bleeding, perforation, and cardiorespiratory complications was 0.22%, 0.03%, and 0.06%, respectively.

DISCUSSION

The complication rate of outpatient colonoscopy is on the order of tenths of a percent, while the process quality is high. The rate of detection of colorectal adenoma and carcinoma is high and the projected benefits for public health are considerable, but the rate of participation is too low.

Hyperglycemia and hypertriglyceridemia may associate with the adenoma-carcinoma transition in colorectal epithelial cells

BACKGROUND AND AIM

Epidemiological studies have suggested the positive correlation between hyperlipidemia and/or hyperglycemia and colorectal cancer risk.

METHODS

We retrospectively examined the association between fasting blood sugar (BS) or triglycerides (TG) and the presence of colorectal adenoma, carcinoma in situ and invasive cancer in 867 patients who received total colonoscopy by medical health check.

RESULTS

An increased TG level, but not a BS level, was significantly associated with the increased risk of adenoma, although with non-independent multivariate analysis. In contrast, an elevated BS level was identified as an independent risk factor for invasive cancer in 93 patients with carcinoma lesions with an odds ratio of 1.74 (P < 0.05).

CONCLUSION

Our data suggest that hypertriglyceridemia and hyperglycemia may correlate with the development of adenoma and invasive cancer, respectively. The effectiveness of strict BS control in patients with hypertriglyceridemia for the prevention of the invasive colorectal carcinoma deserves further studies.

Volume-based Feature Analysis of Mucosa for Automatic Initial Polyp Detection in Virtual Colonoscopy

In this paper, we present a volume-based mucosa-based polyp candidate determination scheme for automatic polyp detection in computed colonography. Different from most of the existing computer-aided detection (CAD) methods where mucosa layer is a one-layer surface, a thick mucosa of 3-5 voxels wide fully reflecting partial volume effect is intentionally extracted, which excludes the direct applications of the traditional geometrical features. In order to address this dilemma, fast marching-based adaptive gradient/curvature and weighted integral curvature along normal directions (WICND) are developed for volume-based mucosa. In doing so, polyp candidates are optimally determined by computing and clustering these fast marching-based adaptive geometrical features. By testing on 52 patients datasets in which 26 patients were found with polyps of size 4-22 mm, both the locations and number of polyp candidates detected by WICND and previously developed linear integral curvature (LIC) were compared. The results were promising that WICND outperformed LIC mainly in two aspects: (1) the number of detected false positives was reduced from 706 to 132 on average, which significantly released our burden of machine learning in the feature space, and (2) both the sensitivity and accuracy of polyp detection have been slightly improved, especially for those polyps smaller than 5mm.

COX-2 expression in sporadic colorectal adenomatous polyps is linked to adenoma characteristics

AIMS

To assess cyclooxygenase-2 (COX-2) expression in sporadic colonic adenomas and to explore the association of COX-2 positivity with adenoma characteristics linked to increased risk of malignant transformation.

METHODS AND RESULTS

COX-2 expression and localization were assessed in 64 colorectal adenomas and 35 paired adjacent normal colonic mucosal biopsy specimens. The number of adenoma specimens was then extended to include polyps exhibiting an increasing degree of epithelial dysplasia. Forty colonic hyperplastic polyps were also identified from the pathology diagnostic database and included in the analysis. Immunohistochemistry was performed with the Envision+ peroxidase-linked biotin-free system incorporating a signal amplification step. There was a statistically significant increase in COX-2 expression in colonic polyps compared with paired adjacent normal mucosa, chi(2) = 40.1, P = 0.001. The probability of COX-2 expression increased along with increasing adenoma size and increasing degree of epithelial dysplasia. Fifty-five per cent of the hyperplastic polyp specimens expressed COX-2.

CONCLUSIONS

This study associates COX-2 epithelial expression with a number of adenoma characteristics that convey an increased risk of malignant transformation. This is in keeping with a positive role for COX-2 in early colorectal carcinogenesis.

Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology

In the United States, colorectal cancer (CRC) is the third most common cancer diagnosed among men and women and the second leading cause of death from cancer. CRC largely can be prevented by the detection and removal of adenomatous polyps, and survival is significantly better when CRC is diagnosed while still localized. In 2006 to 2007, the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology came together to develop consensus guidelines for the detection of adenomatous polyps and CRC in asymptomatic average-risk adults. In this update of each organization's guidelines, screening tests are grouped into those that primarily detect cancer early and those that can detect cancer early and also can detect adenomatous polyps, thus providing a greater potential for prevention through polypectomy. When possible, clinicians should make patients aware of the full range of screening options, but at a minimum they should be prepared to offer patients a choice between a screening test that primarily is effective at early cancer detection and a screening test that is effective at both early cancer detection and cancer prevention through the detection and removal of polyps. It is the strong opinion of these 3 organizations that colon cancer prevention should be the primary goal of screening.

Computed tomographic colonography: clinical value

Computed tomographic colonography (CTC) has the potential to reliably detect polyps in the colon. Its clinical value is accepted for several indications. The main target is screening asymptomatic people for colorectal cancer (CRC). As in large multi-centre trials controversial results were obtained, acceptance of this indication on a large scale is still pending. Agreement exists that in experienced hands screening can be performed with CTC. This emphasizes the importance of adequate and intensive training. Besides this, other problems have to be solved. A low complication profile is mandatory. Perforation rate is very low. Ultra-low dose radiation should be used. When screening large patient cohorts, CTC will need a time-efficient and cost-effective management without too many false positives and additional exploration. Can therefore a cut-off size of polyp detection safely be installed? Is the flat lesion an issue? Can extra-colonic findings be treated efficiently? A positive relationship with the gastro-enterologists will improve the act of screening. Improvements of scanning technique and software with dose reduction, improved 3D visualisation methods and CAD are steps in the good direction. Finally, optimisation of laxative-free CTC could be invaluable in the development of CTC as a screening tool for CRC.

Efficacy, risk factors and complications of endoscopic polypectomy: Ten year experience at a single center

AIM: To examine the efficacy and complications of colonoscopic resection of colorectal polypoid lesions.

METHODS: We retrospectively reviewed 1354 polypectomies performed on 1038 patients over a ten-year period. One hundred and sixty of these were performed for large polyps, those measuring ≥ 20 mm. Size, shape, location, histology, the technique of polypectomy used, complications, drugs assumption and associated intestinal or extra intestinal diseases were analyzed. For statistical analysis, the Pearson χ² test, NPC test and a Binary Logistic Regression were used.

RESULTS: The mean patient age was 65.9 ± 12.4 years, with 671 men and 367 women. The mean size of polyps removed was 9.45 ± 9.56 mm while the size of large polyps was 31.5 ± 10.8 mm. There were 388 pedunculated and 966 sessile polyps and the most common location was the sigmoid colon (41.3%). The most frequent histology was tubular adenoma (55.9%) while for the large polyps was villous (92/160 -57.5%). Coexistent malignancy was observed in 28 polyps (2.1%) and of these, 20 were large polyps. There were 17 procedural bleeding (1.3%) and one perforation. The statistical analysis showed that cancer is correlated to polyp size (P < 0.0001); sessile shape (P < 0.0001) and bleeding are correlated to cardiac disease (P = 0.034), tubular adenoma (P = 0.016) and polyp size.

CONCLUSION: The endoscopic resection is a simple and safe procedure for removing colon rectal neoplastic lesions and should be considered the treatment of choice for large colorectal polyps. The polyp size is an important risk factor for malignancy and for bleeding.

Variation of agreement in polyp size measurement between computed tomographic colonography and pathology assessment: clinical implications

BACKGROUND & AIMS

Clinical management of polyps discovered by computed tomographic (CT) colonography depends on polyp size. However, size measured by CT colonography is an estimate, and its agreement with other measures is not well characterized. We hypothesized that size measurement by CT colonography varies substantially compared with measurement by other methods.

METHODS

We performed a secondary data analysis of a multicenter study of CT colonography in comparison with colonoscopy. Polyp size was determined by CT colonography, at colonoscopy, and measurement prefixation with a ruler. Agreement was assessed using descriptive statistics and Bland-Altman methodology.

RESULTS

Six hundred trial participants completed both tests. Ninety-five percent limits of agreement indicated that estimates of size by CT colonography were between 52% lower to 64% higher than prefixation polyp size estimates. Ninety-five percent limits of agreement stratified by categories of clinical importance indicated that estimates of size by CT colonography were between 44% lower to 84% higher for polyps 0.6 cm or smaller, 44% lower to 44% higher for polyps 0.6 to 0.9 cm, and 48% lower to 22% higher for polyps smaller than 0.6 cm, 44% lower to 44% higher for polyps 0.6 cm to 0.9 cm, and 48% lower to 22% higher for polyps larger than 0.9 cm compared with prefixation estimates. Analysis of participants with 1 identified polyp in the same colon segment showed that categorization based on CT colonography measurement (ie, <0.6 cm, 0.6-0.9 cm, or >0.9 cm) differed from prefixation measurement for 43% of participants.

CONCLUSIONS

Polyp size estimation by CT colonography varies from prefixation and colonoscopic measures of size. Future studies should clarify whether size estimation by CT colonography is sufficiently reliable as a primary factor to guide clinical management.

Risk factors for high-grade dysplasia or carcinoma in colorectal adenoma cases treated with endoscopic polypectomy

OBJECTIVE

Our aim is to establish the risk factors for carrying high-grade dysplasia or carcinoma by analyzing endoscopically treated adenoma cases.

METHODS

Patients who underwent endoscopic polypectomy at our hospitals between January 2003 and August 2004 were analyzed.

RESULTS

A total of 889 patients (mean age: 63+/-11 years), and 1486 adenomas resected from these patients, were included in the analysis. Seventy-five adenomas (5%) from 72 patients (8%) were found to have high-grade dysplasia or carcinoma. Among patient factors, female sex [odds ratio (OR) 2.25, 95% confidence intervals (CI)=1.34-3.76], presence of multiple adenomas (OR=2.15, 95% CI=1.15-4.00), older age (OR=1.02, 95% CI=1.00-1.04), and rectal bleeding as the indication for colonoscopy (OR=2.57, 95% CI=1.34-4.92) were identified as the significant risk factors for carrying high-grade dysplasia or carcinoma using the multivariate analysis. In addition, a size of > or = 10 mm (OR=10.83, 95% CI=5.86-20.0), flat appearance (OR=3.91, 95% CI=2.20-6.95), and location on the left side of the colon (OR=1.80, 95% CI=1.03-3.13) were identified as tumor risk factors.

CONCLUSION

Distinct factors were proved to be associated with high-grade dysplasia or carcinoma. These results are useful to select lesions that require immediate treatment. Moreover, female sex as a risk factor raises an interesting problem regarding the progression from adenoma to carcinoma.

Small and diminutive polyps detected at screening CT colonography: a decision analysis for referral to colonoscopy

OBJECTIVE

The objective of this study was to assess the clinical and economic impact of colonoscopic referral for small and diminutive polyps detected at CT colonography (CTC) screening.

MATERIALS AND METHODS

A decision analysis model was constructed incorporating the expected polyp distribution, advanced adenoma prevalence, colorectal cancer (CRC) risk, CTC performance, and costs related to CRC screening and treatment. The model conservatively assumed that CRC risk was independent of advanced adenoma size. The number of diminutive (< or = 5 mm), small (6-9 mm), and large (> or = 10 mm) CTC-detected polyps needed to be removed to detect one advanced adenoma or prevent one CRC over a 10-year time horizon was calculated. The cost-effectiveness of polypectomy was also assessed.

RESULTS

The estimated 10-year CRC risk for unresected diminutive, small, and large polyps was 0.08%, 0.7%, and 15.7%, respectively. The number of diminutive, small, and large polyps needed to be removed to avoid leaving behind one advanced adenoma was 562, 71, and 2.5, respectively; similarly, 2,352, 297, and 10.7 polypectomies would be needed, respectively, to prevent one CRC over 10 years. The incremental cost-effectiveness ratio of removing all diminutive and small CTC-detected polyps was $464,407 and $59,015 per life-year gained, respectively. Polypectomy for large CTC-detected polyps yielded a cost-saving of $151 per person screened.

CONCLUSION

For diminutive polyps detected at CTC screening, the very low likelihood of advanced neoplasia and the high costs associated with polypectomy argue against colonoscopic referral, whereas removal of large CTC-detected polyps is highly effective. The yield of colonoscopic referral for small polyps is relatively low, suggesting that CTC surveillance may be a reasonable management option.

SFRP2 methylation in fecal DNA--a marker for colorectal polyps

INTRODUCTION

DNA methylation of secreted frizzled-related proteins (SFRPs) can be detected in colorectal cancer (CRC) tissue, in tissue of adenomas, and in aberrant crypt foci, whereas in normal colorectal mucosa tissue, SFRP genes are unmethylated. Recently, our study group was able to demonstrate SFRP2 methylation as the most sensitive single DNA-based marker in stool for identification of CRC. The purpose of this study was to clarify whether SFRP2 methylation in fecal DNA can be found in stool of individuals with hyperplastic and adenomatous colorectal polyps.

MATERIALS AND METHODS

Patients who were diagnosed with colorectal polyps or showed negative colonoscopy were included in this study. DNA from stool samples was isolated. SFRP2 methylation was assessed by means of MethyLight.

RESULTS

Stool samples from 68 individuals were checked for DNA content; 23% of the samples (6 of 26) from healthy controls, 46% of the samples (6 of 13) from patients with hyperplastic polyps, and 45% of the samples (13 of 29) from patients with adenomas were positive for human DNA. SFRP2 methylation in stool samples was found in none of the healthy controls, in 33% (2 of 6) patients with hyperplastic polyps, and in 46% (6 of 13) patients with adenomas. Statistical analysis revealed that the frequency of SFRP2 methylation increased significantly (P=0.028) from healthy controls to patients with hyperplastic polyps and to patients with adenomas.

CONCLUSIONS

In the current study, we report for the first time that SFRP2 methylation in fecal DNA increases significantly from healthy controls to patients with hyperplastic polyps and to patients with adenomas. SFRP2 methylation may serve as a marker for molecular stool-based adenoma and CRC screening.

CT colonography versus colonoscopy for the detection of advanced neoplasia

BACKGROUND

Advanced neoplasia represents the primary target for colorectal-cancer screening and prevention. We compared the diagnostic yield from parallel computed tomographic colonography (CTC) and optical colonoscopy (OC) screening programs.

METHODS

We compared primary CTC screening in 3120 consecutive adults (mean [+/-SD] age, 57.0+/-7.2 years) with primary OC screening in 3163 consecutive adults (mean age, 58.1+/-7.8 years). The main outcome measures included the detection of advanced neoplasia (advanced adenomas and carcinomas) and the total number of harvested polyps. Referral for polypectomy during OC was offered for all CTC-detected polyps of at least 6 mm in size. Patients with one or two small polyps (6 to 9 mm) also were offered the option of CTC surveillance. During primary OC, nearly all detected polyps were removed, regardless of size, according to established practice guidelines.

RESULTS

During CTC and OC screening, 123 and 121 advanced neoplasms were found, including 14 and 4 invasive cancers, respectively. The referral rate for OC in the primary CTC screening group was 7.9% (246 of 3120 patients). Advanced neoplasia was confirmed in 100 of the 3120 patients in the CTC group (3.2%) and in 107 of the 3163 patients in the OC group (3.4%), not including 158 patients with 193 unresected CTC-detected polyps of 6 to 9 mm who were undergoing surveillance. The total numbers of polyps removed in the CTC and OC groups were 561 and 2434, respectively. There were seven colonic perforations in the OC group and none in the CTC group.

CONCLUSIONS

Primary CTC and OC screening strategies resulted in similar detection rates for advanced neoplasia, although the numbers of polypectomies and complications were considerably smaller in the CTC group. These findings support the use of CTC as a primary screening test before therapeutic OC.

Malignancy risk of small polyps and related factors

The aim of this study was to determine the risk of polyps <6 and between 6 and 10 mm in terms of progression to malignancy and to evaluate the influence of age, gender, and colonic localization on malignancy development. Thirteen hundred sixty-nine polyps <10 mm identified in 680 patients were retrospectively evaluated. Sixty-seven and two-tenths percent of polyps <10 mm were of a neoplastic nature. The incidence of neoplasia was higher in left-sided and small polyps than diminutive polyps. In patients older than 60 years, small polyps showed a higher rate of high-risk histology than diminutive polyps,while the same relationship did not exist in other age groups. In male patients over 60 years of age, the rate of high-risk histology was higher in small polyps than in diminutive polyps.

Stool DNA analysis detects premorphological colorectal neoplasia: a case report

We found, in an asymptomatic patient with familial occurrence of malignancy, that mutations in the oncogene Kras could be detected in stool 18 months before a premalignant polyp was detected and removed endoscopically. Colorectal cancers usually develop from benign adenomas in a lengthy period of 5-10 years. During this period, several major biochemical pathways are involved, each characterized by one or several genetic alterations. Our patient did not present any signs or symptoms of colorectal disease during his two visits to the endoscopist. This case report shows that the use of genetic markers in stool testing has the potential to detect colon cancer in its very early stages when treatment is simple and often successful.

Endoscopic mucosal resection of 161 cases of large sessile or flat colorectal polyps

OBJECTIVE

Large sessile or flat colorectal polyps, which are traditionally treated surgically, may be amenable to endoscopic mucosal resection (EMR), often using a piecemeal method. Appropriate selection of lesions and a careful technique may enhance the efficacy of EMR for polyps >or=20 mm in diameter without compromising safety. The aim of this study was to identify the factors that may be predictive of the risk of polyp recurrence.

MATERIAL AND METHODS

A retrospective analysis was conducted on the outcome of 161 polyps >or=20 mm in diameter, treated by piecemeal EMR at a single centre using the "lift and cut" technique. All records were reviewed for polyp size, site, morphology and histology. Polypectomy technique, patient follow-up, polyp recurrence and surgical interventions were also recorded.

RESULTS

Over an 8-year period, 161 colonic polyps measuring >or=20 mm were removed by EMR. Follow-up data were available for 149 cases (93%) with a mean polyp diameter of 32.5 mm; the total success rate of endoscopic polyp removal was 95.4%. The number of cases requiring 1, 2, 3, 4 and 6 attempts at EMR was 89 (60%), 36 (24%), 14 (9%), 2 (1.3%) and 1 (0.7%), respectively. Recurrence was significantly related to polyp size (p<0.001). There was no statistically significant relationship between site and recurrence. Seven patients (4.6%) underwent surgical intervention after EMR because of failed clearance. There were no post-EMR perforations and significant bleeding was reported in only two patients (1.7%).

CONCLUSIONS

With careful attention to technique, piecemeal EMR is a safe option for the resection of most sessile and flat colorectal polyps >or=20 mm in size. A stricter follow-up may be required for larger lesions because of a higher risk of recurrence.

Serrated neoplasias and de novo carcinomas in ulcerative colitis: a histological study in colectomy specimens

BACKGROUND AND AIM

Cancer in ulcerative colitis (UC) originates in dysplastic crypts, adenomatous growths (UCAG), and UC-associated adenomas (UCAD). The aim of the present study was to compare the histological phenotypes between UCAG, UCAD, and sporadic colorectal adenomas in non-colitics (non-UCAD), as well as between UC-associated carcinomas (UCC) and carcinomas in non-colitic patients (non-UCC).

METHODS

Three thousand and forty nine sections from 96 colectomy specimens in patients with UC-pancolitis and carcinoma were reviewed.

RESULTS

Villous phenotypes were more frequent in UCAG (48%) than in UCAD (26%) and non-UCAD (11%), and serrated phenotypes more frequent in UCAD (29%) than in UCAG (12%) and non-UCAD (8%). Tubular phenotypes were far less frequent in UCAG (14%) than in UCAD (45%) and non-UCAD (80%). Villous and signet ring cell cancer phenotypes were more frequent in UCC (22% and 8%, respectively) than in non-UCC (9% and 0.8%, respectively). Six UCC (5.6%) were de novo carcinomas.

CONCLUSIONS

Invasive carcinomas were found in one-half of the UCAG and in one-third of the UCAD, indicating that both lesions are important in cancer development in UC. The different proportions of histological phenotypes found in UCAG, UCAD, and non-UCAD on the one hand, and UCC and non-UCC on the other, suggest that chronic protracted inflammation might have modified the stem cell receptors that receive the molecular signals that program structural configurations in neoplastic glands. This is the first study reporting the occurrence of serrated and microtubular UCAG and of de novo carcinomas in UC.

Common polymorphisms in 5-lipoxygenase and 12-lipoxygenase genes and the risk of incident, sporadic colorectal adenoma

BACKGROUND

Lipoxygenases (LOX) are major enzymes that metabolize arachidonic acid to hydroxyl-eicosatetraenoic acids and leukotrienes, which have been implicated in inflammation and colorectal cancer risk. Polymorphisms in LOX genes may influence their function and/or expression and, thus, may modify the risk for colorectal adenoma. The authors investigated the associations of 3 polymorphisms (2 in 5-LOX, -1708 guanine-->adenine and 21 cytosine-->thymine; and 1 in 12-LOX, arginine 261 glutamine [Arg261Gln]) in LOX genes with the risk of colorectal adenoma and also explored possible interactions of these polymorphisms with several inflammation-pathway or arachidonic acid metabolism-pathway related factors with the risk of colorectal adenoma.

METHODS

By using data from a community-based, case-control study of incident, sporadic colorectal adenoma that included 162 cases and 211 controls, the authors constructed multiple logistic regression models to estimate the odds ratios (OR) and 95% confidence intervals (95% CI) of colorectal adenoma after adjusting for potential confounders.

RESULTS

Overall, there were no significant associations of the 2 5-LOX polymorphisms with the risk of colorectal adenoma. However, there was an inverse association between the Arg261Gln polymorphism in 12-LOX and colorectal adenoma (OR, 0.63; 95% CI, 0.40-1.00). A significant interaction also was observed between the 12-LOX polymorphism (Arg261Gln) and the use of nonsteroidal anti-inflammatory drugs (P(interaction) = .02).

CONCLUSIONS

The current results suggested that polymorphisms of LOX genes may act independently or with other factors to affect the risk of colorectal adenoma. Further studies will be needed to confirm these findings. Cancer 2007 (c) 2007 American Cancer Society.

Characteristics of advanced adenomas detected at CT colonographic screening: implications for appropriate polyp size thresholds for polypectomy versus surveillance

OBJECTIVE

Advanced adenomas are the primary target in colorectal screening. The purpose of this study was to delineate the prevalence and imaging characteristics of advanced adenomas detected at screening CT colonography (CTC) and the rates of invasive carcinoma and high-grade dysplasia for various polyp size categories. These observations may be a basis for formulation of polypectomy thresholds and CTC surveillance strategies.

MATERIALS AND METHODS

The imaging and pathologic findings for polyps measuring 6 mm or more obtained from a CTC screening population of 3,536 persons during a 32-month period were retrospectively reviewed. From this group, prevalence, size, histologic features, morphologic features, and location of advanced adenomas were tabulated. Advanced adenomas were defined by size (> or = 10 mm) and/or histologic findings (prominent villous component or high-grade dysplasia).

RESULTS

A total of 123 (38.3%) of 321 adenomas measuring 6 mm or more were classified as advanced, the overall prevalence being 3.1% (111 of 3,536 patients). The mean size of advanced adenomas was 16.6 +/- 11.6 mm; most of the lesions (116/123, 94.3%) qualified as advanced on the basis of the size criterion alone. The seven lesions measuring 6-9 mm constituted 3.4% (7/205) of all medium-sized adenomas. The largest percentage (65/123, 52.8%) of the advanced adenomas had tubular histologic features, followed by tubulovillous (50/123, 40.6%), villous (5/123, 4.1%), and serrated (3/123, 2.4%) histologic features. High-grade dysplasia was uncommon (6/123, 4.9%), typically occurring in large lesions. Seven cases of cancer were detected, all lesions measuring 10 mm or more in size. The majority of advanced adenomas were classified as sessile (57/123, 46.3%) or pedunculated (57/123, 46.3%); a small percentage were flat (9/123, 7.3%). Advanced adenomas were located in the proximal colon in 43.9% (54/123) and distal colon in 56.1% (69/123) of the cases.

CONCLUSION

Advanced adenomas were generally large (> or = 10 mm in size); only a small percentage were medium sized (6-9 mm). There was a very low prevalence of high-grade dysplasia and invasive carcinoma in this series, particularly in the medium-sized group of lesions. These findings lend support to the practice of CTC screening in which large polyp size is used as a surrogate measure for the possible presence of advanced histologic features and medium-sized lesions are followed with noninvasive surveillance protocols.

Estimating the referral rate for cancer genetic assessment from a systematic review of the evidence

To estimate the optimal proportion of new patients diagnosed with cancer who require assessment and evaluation for familial cancer genetic risk, based on the best evidence available. We identified evidence of the patients who require assessment for familial genetic risk when diagnosed with cancer through extensive literature reviews and searches of guidelines. Epidemiological data on the distribution of cancer type, presence of a family history, age and other factors that influence referral for genetic assessment were identified. Decision trees were constructed to merge the evidence-based recommendations with the epidemiological data to calculate the optimal proportion of patients who should be referred. We identified 'high probability' and 'moderate probability' groups for having a genetic susceptibility. The proportion of patients diagnosed with cancer in Australia who have a high probability of having a genetic predisposition and who should be referred for genetic assessment is 1%. If the moderate probability group is also assessed this proportion increases to 6%. This model has identified the proportion of new patients diagnosed with cancer who should be referred for genetic assessment. This data is the first step in determining the resources required for provision of an adequate cancer genetic service.

Clinicopathologic and immunohistochemical study of small apparently "de novo" colorectal adenocarcinomas

Rarely, adenocarcinomas of the colorectum develop as small (< or =1.0 cm) rapidly invasive tumors without an obvious adenomatous or "in situ" component. These tumors have been termed "de novo" carcinomas. Although it is believed by some that these tumors are more aggressive than conventional large adenocarcinomas with an identifiable in situ component, little is known about the biologic characteristics and natural history of these lesions. The aim of this study was to evaluate and compare the pathologic features, biologic characteristics, and natural history of small apparently de novo invasive colorectal adenocarcinomas with conventional large (>1.0 cm) carcinomas. Routinely processed specimens from 20 patients (M/F ratio: 13/7; mean age: 65 y) with small apparently de novo invasive colorectal adenocarcinomas (all < or =1.0 cm in size) were evaluated for a variety of clinical and pathologic features. In addition, immunostains for p53, beta-catenin, DPC4, hMLH1, hMSH2, and MGMT were evaluated in all cases. The findings in this group of cases were compared with those from 20 control patients (M/F ratio: 8/12; mean age: 60 y) with stage-matched conventional "large" colorectal adenocarcinomas (all >1.0 cm in size). Patients were followed for a mean of 52.6 and 60.6 months, respectively, for the 2 groups. Small apparently de novo invasive adenocarcinomas were present in the left colon, transverse colon, and right colon in 85%, 10%, and 5% of cases, respectively. Their mean size was 7 mm (range: 3 to 10 mm). All cases were stage T1 and the majority were moderately differentiated (75%). Only 1 (5%) patient had lymph node metastases. Two (10%) cases were mucinous and only 1 (5%) showed prominent tumor infiltrating lymphocytes. Upon complete sectioning of the tissue blocks of tumor, residual foci of adenomatous epithelium were present in 16/20 (80%) cases, of which 75% contained foci of high-grade dysplasia. P53 and nuclear beta-catenin staining was present in 70% and 85% of cases, respectively, but only 5 cases (25%) showed loss of DPC4. Loss of MGMT expression was seen in 5 cases (25%), loss of hMSH2 in only 1 case (5%), and none showed loss of hMLH1. Only 2 patients (10%) developed visceral metastases upon follow-up. Control patients had similar demographic features, clinical outcome, anatomic distribution of tumors, degree of differentiation, and prevalence of positivity for the immunostains noted above, to the study cases. In our patient population, true small de novo colorectal adenocarcinomas, tumors that lack an identifiable adenomatous component, are exceedingly rare, because complete tissue sectioning reveals residual adenomatous tissue in the majority of cases. The biologic characteristics and natural history of small carcinomas with a minimal dysplastic component, and those with no identifiable adenomatous component, are similar to conventional large (>1 cm) adenocarcinomas, and, thus, they should probably be treated similarly.

An improved electronic colon cleansing method for detection of polyps by virtual colonoscopy

Electronic colon cleansing (ECC) aims to segment the colon lumen from the patient abdominal image acquired with colonic material tagging by oral contrast and other means, so that a virtual colon model can be constructed. Virtual colonoscopy (VC) navigates through the colon model looking for polyps in a similar manner as the fiber optic colonoscopy does. We had built an ECC pipeline for the commercial VC system of Viatronix Inc. In this paper, we present an improved ECC method. It is based on a partial -volume image -segmentation framework, which is derived using the well-established statistical expectation-maximization algorithm. The presented ECC method was evaluated by both visual inspection on the cleansed colon lumens and computer-aided detection of polyps (CADpolyp) using 20 patient datasets. Compared to our previous ECC pipeline, this presented new method demonstrates improvement in both visual judgment and CADpolyp.

Association of metabolic syndrome with proximal and synchronous colorectal neoplasm

BACKGROUND & AIMS

Metabolic syndrome and its associated morbidities have become a major public health problem in both developed and developing countries. Insulin resistance, the core mechanism of metabolic syndrome, has been associated with the development of colorectal neoplasm, but the interrelation between metabolic syndrome and colon cancer is rarely addressed. Our study aimed to determine whether metabolic syndrome is associated with the risk and clinical presentation of colorectal neoplasia.

METHODS

Consecutive 4277 ethnic Chinese who received complete total colonoscopy and thorough health checkups were enrolled. Both National Cholesterol Education Program's Adult Treatment Panel III and modified Asian criteria were used for defining metabolic syndrome. Logistic regression modeling was used to elucidate the association between colorectal neoplasia and metabolic syndrome. The impact of metabolic syndrome on distribution and number of colorectal neoplasia was also assessed.

RESULTS

Of all those enrolled, 27.1% of men and 18.9% of women met the criteria of metabolic syndrome, and 9.8% had colorectal neoplasia. Metabolic syndrome was associated with odds ratio (OR) of 1.35 (95% confidence interval [CI], 1.05-1.73) for colorectal neoplasia. OR was 0.96 (95% CI, 0.67-1.38) for distal lesions, 1.62 (95% CI, 1.14-2.30) for proximal lesions, 2.15 (95% CI, 1.40-3.31) for synchronous lesions, and 2.30 (95% CI, 1.42-3.72) for synchronous lesions located at both sides of colon.

CONCLUSIONS

Subjects with metabolic syndrome have a higher risk of colon neoplasia at the proximal colon and synchronous lesions at both sides of the colon. These findings will help future colon cancer screening and prevention in patients with metabolic syndrome.

The management of small polyps found by virtual colonoscopy: results of a decision analysis

BACKGROUND & AIMS

There is a firm consensus that larger (> or =10 mm) colonic polyps should be removed; however, the importance of removing smaller polyps (<10 mm) is more controversial. If computed tomographic colonography (CTC) is used for colorectal cancer screening, the majority of polypoid lesions identified will be less than 10 mm in size. Decision-analytic techniques were used to compare the outcomes of 2 management strategies for smaller (6-9 mm) polyps discovered by CTC.

METHODS

Hypothetic average-risk patients who had undergone a CTC examination and found to have a small (6-9 mm) polyp were simulated to either: (1) undergo immediate colonoscopy for polypectomy (COLO), or (2) wait 3 years for a repeat CTC examination (WAIT). A Markov model was constructed to analyze outcomes including the number of deaths and cancers after a 3-year follow-up period or time horizon. Values for the model parameters were derived from the published literature and from Surveillance Epidemiology and End Results data, and an extensive sensitivity analysis was performed.

RESULTS

The COLO strategy resulted in 14 total deaths per 100,000 patients compared with 79 total deaths in the WAIT strategy, for a difference of 65 deaths. The COLO strategy resulted in 39 cancers per 100,000 patients vs 773 in the WAIT strategy, for a difference of 734 cancers. Sensitivity analysis found that model findings were robust and only sensitive at extreme parameter values.

CONCLUSIONS

Managing smaller polyps detected on a screening CTC with another CTC examination 3 years later likely will result in more deaths and cancers than immediate colonoscopy and polypectomy.

Strengths and weaknesses of dark-lumen MR colonography: clinical relevance of polyps smaller than 5 mm in diameter at the moment of their detection

PURPOSE

To assess the clinical relevance of dark-lumen MR colonography (MRC) for the detection of colorectal lesions using conventional colonoscopy (CC) and histopathologic examinations as reference standard.

MATERIALS AND METHODS

A total of 72 patients underwent MRC and CC. MRC was performed using a contrast-enhanced high spatial resolution T1 weighted 3D volumetric interpolated breathhold examination (VIBE)-sequence. All removed colorectal lesions were evaluated by an experienced pathologist.

RESULTS

CC confirmed 65 polyps less than 5 mm in diameter. Non of those lesions could be detected using MRC. Just two (4%) of the 49 removed lesions smaller than 5 mm showed signs of dysplasia. Additionally, CC confirmed 25 polyps between 6-15 mm in diameter (MRC 22). All those 25 lesions were removed in CC. Only four (16%) of those polyps showed signs of dysplasia and malignancy (11, 13, 13 and 15 mm).

CONCLUSION

Dark-lumen MRC failed to detect all polyps smaller than 5 mm in diameter which are generally not clinically relevant at the moment of their detection and thus can be kept under surveillance. However, MRC as a non-invasive imaging modality is a promising alternative to CC in the detection of clinically relevant polyps larger than 5 mm in diameter.

Comparison of microsatellite instability, CpG island methylation phenotype, BRAF and KRAS status in serrated polyps and traditional adenomas indicates separate pathways to distinct colorectal carcinoma end points

The aim of this study was to compare BRAF and KRAS, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI) status in each of the histologic categories, including end-point carcinomas with residual adenoma, of the serrated polyp neoplasia pathway and the traditional (nonserrated) adenoma-carcinoma sequence. Deoxyribonucleic acid (DNA) was extracted from the selected samples and assayed for BRAF, KRAS2 codon12, 13, CIMP using markers hMLH1, MGMT, MINT1, MINT2, p16, and MSI using an assay for BAT25 and BAT26. A BRAF mutation was present in 82% of serrated carcinomas (SCas), 62% of serrated adenomas (SAs), 83% of serrated polyps with abnormal proliferation (SPAPs-syn. sessile serrated adenoma [SSA]), 76% of microvesicular serrated polyps (MVSPs), and was not found in any of the histologic categories of the traditional adenoma-carcinoma sequence. KRAS2 mutations were found in 43% of the goblet cell serrated polyp (GCSP) category, 13% of MVSPs, 7% of SPAPs, and 24% of SAs; in 26% of large traditional adenoma (lTAs) compared with small traditional adenomas (sTAs) (0/30; P<0.005) and in 37.3% of traditional carcinomas (TCa). CIMP-H (>1 marker positive) was significantly more frequent in SPAP, SA, and SCa compared with MVSP (P<0.05); CIMP-H was present in 10% of sTAs but was found more frequently in lTA (44.4%; OR 7.2; P=0.007) and TCa (38.9%; OR 5.8; P=0.007). Higher CIMP levels (4 or more markers positive) were significantly more frequent in advanced categories of the serrated pathway (SAs [31%] and SCas [30%]) compared with lTAs [0%] and TCAs [3.4%] (OR 12.2; P=0.02). MSI-H was identified only in the adenocarcinoma component of SCas (9/11) or in the contiguous SAs (3/7). The findings indicate that a BRAF mutation is a specific marker for a serrated polyp pathway that has its origin in a hyperplastic polyp (MVSP) and a potential end point as MSI carcinoma. CIMP-High (CIMP-H) develops early in this sequence and MSI-H develops late. The data provided a less complete picture of a second serrated pathway, identified by a KRAS2 mutation in SAs, but showed that the progressive stages of both iterations of the serrated neoplasia pathway are separate and distinct from those of the traditional adenoma-carcinoma sequence.

Colonoscopic withdrawal times and adenoma detection during screening colonoscopy

BACKGROUND

Colonoscopy is commonly used to screen for neoplasia. To assess the performance of screening colonoscopy in everyday practice, we conducted a study of the rates of detection of adenomas and the amount of time taken to withdraw the colonoscope among endoscopists in a large community-based practice.

METHODS

During a 15-month period, 12 experienced gastroenterologists performed 7882 colonoscopies, of which 2053 were screening examinations in subjects who had not previously undergone colonoscopy. We recorded the numbers, sizes, and histologic features of the neoplastic lesions detected during screening, as well as the duration of insertion and of withdrawal of the colonoscope during the procedure. We compared rates of detection of neoplastic lesions among gastroenterologists who had mean colonoscopic withdrawal times of less than 6 minutes with the rates of those who had mean withdrawal times of 6 minutes or more. According to experts, 6 minutes is the minimum length of time to allow adequate inspection during instrument withdrawal.

RESULTS

Neoplastic lesions (mostly adenomatous polyps) were detected in 23.5% of screened subjects. There were large differences among gastroenterologists in the rates of detection of adenomas (range of the mean number of lesions per subject screened, 0.10 to 1.05; range of the percentage of subjects with adenomas, 9.4 to 32.7%) and in their times of withdrawal of the colonoscope from the cecum to the anus (range, 3.1 to 16.8 minutes for procedures during which no polyps were removed). As compared with colonoscopists with mean withdrawal times of less than 6 minutes, those with mean withdrawal times of 6 minutes or more had higher rates of detection of any neoplasia (28.3% vs. 11.8%, P<0.001) and of advanced neoplasia (6.4% vs. 2.6%, P=0.005).

CONCLUSIONS

In this large community-based gastroenterology practice, we observed greater rates of detection of adenomas among endoscopists who had longer mean times for withdrawal of the colonoscope. The effect of variation in withdrawal times on lesion detection and the prevention of colorectal cancer in the context of widespread colonoscopic screening is not known. Ours was a preliminary study, so the generalizability and implications for clinical practice need to be determined by future studies.

Perceptive errors in CT colonography

Published results to date have indicated a good per patient sensitivity of computed tomographic colonography (CTC) for colorectal cancer and for polyps measuring 10 mm or more together with a very good specificity. Sensitivity and specificity for polyps in the range of 6-10 mm are moderate. These results, however, can be achieved only with meticulous attention to technique including adequate colonic distention, and acquisition of supine and prone thin-section computed tomographic (CT) images. Moreover, there is a significant learning curve involved in the interpretation of CTC studies, with performance statistics improving with operator experience. Radiologists must be comfortable in reporting directly from workstation monitors and have access to and be familiar with software for multiplanar and endoluminal reconstructions. In addition to maximize polyp detection and minimize false positive results, reporting radiologists must have a working knowledge of normal colorectal anatomy and pathology on CTC and be familiar with potential pitfalls in interpretation. Besides the description of several possible causes for perceptive errors, also a literature search of perceptive errors in CTC is included in this paper.

Determinants of compliance with colonoscopy in patients with adenomatous colon polyps in a veteran population

AIM

To determine factors affecting compliance of a follow-up colonoscopy in patients with previously diagnosed adenomatous colon polyps.

METHODS

A retrospective review was performed on patients with adenomatous polyps excised between January and December 1998. Twenty-nine clinical factors were assessed in patients grouped into whether they were compliant (n = 81) or noncompliant (n = 38) with follow-up colonoscopy. Significant variables by univariate analysis were included in multivariate regression.

RESULTS

One hundred and nineteen patients with adenomatous colon polyps were identified. Of 119 patients, 114 had a documented recommendation for follow-up of 5 years or less, with 69% having been compliant. In a univariate analysis, greater number of polyps (P = 0.04), NSAID use (P = 0.02), statin use (P = 0.005), first-degree relatives with colon cancer (P = 0.05) and compliance with out-patient clinic follow-up (P < 0.001) were significantly associated with patient compliance. Multivariate analysis revealed statin use (P = 0.05), first-degree relatives with colon cancer (P = 0.06) and compliance with out-patient clinic follow-up (P < 0.001) were independent predictors of compliance.

CONCLUSIONS

History of statin use and family history of colon cancer are good predictors of compliance. The strongest predictor can be anticipated with compliance assessed with encounters for other visits. Strong efforts should be directed at improving patient education about colon cancer by the physician and facilitating patient compliance.

MR colonography for the assessment of colonic anastomoses

PURPOSE

To assess colonic anastomoses in patients after surgical treatment by means of MR colonography (MRC) in comparison with conventional colonoscopy (CC).

MATERIALS AND METHODS

A total of 39 patients who had previously undergone colonic resection and end-to-end-anastomosis were included in the study. MRI was based on a dark-lumen approach. Contrast-enhanced T1-weighted (T1w) three-dimensional (3D) images were collected following the rectal administration of water for colonic distension. The MRC data were evaluated by two radiologists. The criteria employed to evaluate the anastomoses included bowel wall thickening and increased contrast uptake in this region. Furthermore, all other colonic segments were assessed for the presence of pathologies.

RESULTS

In 23 and 20 patients the anastomosis was rated to be normal by MRC and CC, respectively. In three patients CC revealed a slight inflammation of the anastomosis that was missed by MRI. A moderate stenosis of the anastomosis without inflammation was detected by MRC in five patients, which was confirmed by CC. In the remaining 11 patients a relevant pathology of the anastomosis was diagnosed by both MRC and CC. Recurrent tumor was diagnosed in two patients with a history of colorectal carcinoma. In the other nine patients inflammation of the anastomosis was seen in seven with Crohn's disease (CD) and two with ulcerative colitis. MRC did not yield any false-positive findings, resulting in an overall sensitivity/specificity for the assessment of the anastomosis of 84%/100%.

CONCLUSION

MRC represents a promising alternative to CC for the assessment of colonic anastomoses in patients with previous colonic resection.

Evaluation of the accuracy of serum MMP-9 as a test for colorectal cancer in a primary care population

BACKGROUND

Bowel cancer is common and is a major cause of death. Meta-analysis of randomised controlled trials estimates that screening for colorectal cancer using faecal occult blood (FOB) test reduces mortality from colorectal cancer by 16%. However, FOB testing has a low positive predictive value, with associated unnecessary cost, risk and anxiety from subsequent investigation, and is unacceptable to a proportion of the target population. Increased levels of an enzyme called matrix metalloproteinase 9 (MMP-9) have been found to be associated with colorectal cancer, and this can be measured from a blood sample. Serum MMP-9 is potentially an accurate, low risk and cost-effective population screening tool. This study aims to evaluate the accuracy of serum MMP-9 as a test for colorectal cancer in a primary care population.

METHODS/DESIGN

People aged 50 to 69 years, who registered in participating general practices in the West Midlands Region, will be asked to complete a questionnaire that asks about symptoms. Respondents who describe any colorectal symptoms (except only abdominal bloating and/or anal symptoms) and are prepared to provide a blood sample for MMP9 estimation and undergo a colonoscopy (current gold standard investigation) will be recruited at GP based clinics by a research nurse. Those unfit for colonoscopy will be excluded. Colonoscopies will be undertaken in dedicated research clinics. The accuracy of MMP-9 will be assessed by comparing the MMP-9 level with the colonoscopy findings, and the combination of factors (e.g. symptoms and MMP-9 level) that best predict a diagnosis of malignancy (invasive disease or polyps) will be determined.

DISCUSSION

Colorectal cancer is a major cause of morbidity and mortality. Most colorectal cancers arise from adenomas and there is a period for early detection by screening, but available tests have risks, are unacceptable to many, have high false positive rates or are expensive. This study will establish the potential of serum MMP-9 as a screening test for colorectal cancer. If it is confirmed as accurate and acceptable, this serum marker has the potential to assist with reducing the morbidity and mortality from colorectal cancer.

An improved electronic colon cleansing method for detection of colonic polyps by virtual colonoscopy

Electronic colon cleansing (ECC) aims to segment the colon lumen from a patient abdominal image acquired using an oral contrast agent for colonic material tagging, so that a virtual colon model can be constructed. Virtual colonoscopy (VC) provides fly-through navigation within the colon model, looking for polyps on the inner surface in a manner analogous to that of fiber optic colonoscopy. We have built an ECC pipeline for a commercial VC navigation system. In this paper, we present an improved ECC method. It is based on a partial-volume (PV) image-segmentation framework, which is derived using the well-established statistical expectation-maximization algorithm. The presented ECC method was evaluated by both visual inspection and computer-aided detection of polyps (CADpolyp) within the cleansed colon lumens obtained using 20 patient datasets. Compared to our previous ECC pipeline, which does not sufficiently consider the PV effect, the method presented in this paper demonstrates improved polyp detection by both visual judgment and CADpolyp measure.

A Monotonous Population of Elongated Cells (MPECs) in Colorectal Adenoma Indicates a High Risk of Metachronous Cancer

Accurate predictors for metachronous colorectal cancer (CRC) development after polypectomy are lacking. We evaluated the prognostic value of classical clinicopathologic features and a monotonous population of elongated cells (MPECs) in colorectal adenomas from 171 consecutively selected population-based patients with long-term follow-up. Quantitative image analysis, and univariate and multivariate regression analysis were applied. Ten of 171 adenomas (5.8%) developed metachronous CRC (defined as >24 mo interval and >5 cm from the index adenoma to the cancer). Median follow-up of adenomas with metachronous CRC was 68.4 and without cancer 149.7 months (range: 25 to 192 and 25 to 256, respectively). The most prognostic classical features were the localization of the marker adenoma as proximal (ie, in the cecum through transverse colon) versus distal from the transverse colon [P=0.0003, hazard ratio (HR)=8] and the number of polyps found during colonoscopy (<or=2 vs.>2, P=0.002, HR=6). Quantitative features of the MPECs included the longest nuclear axis and variance of the number of nuclei with 2 neighbors (higher and lower in cancer cases, respectively). Of the 171 adenomas, 50 (29%) had MPECs, of which 9 (18%) patients developed metachronous CRC at follow-up, contrasting 1/121 (0.8%) without MPECs (P=0.0003, HR=23). MPECs occurred in both low-grade and high-grade dysplasia, and in tubular and (tubulo) villous adenomas. MPECs had the strongest predictive value for metachronous CRC development. Adenomas proximally located had additional value but only if they were MPEC positive (which only occurred in 5 adenomas, 3 of which (60%) developed cancer). Having more than 2 polyps also had additional prognostic value but only in MPEC-negative adenomas [10 cases; 1 (10%) developed cancer]. Dysplasia grade and histologic growth pattern had no additional value. Thus, colorectal adenomas with subsequent metachronous cancer development can be identified more accurately with MPECs than with classical prognostic factors.

Cost-benefit analysis of screening colonoscopy in 40- to 50-year-old first-degree relatives of patients with colorectal cancer

BACKGROUND AND AIMS

As shown previously, 40- to 50-year-old first-degree relatives of patients with colorectal cancer (CRC) have significantly more colorectal adenomas than controls of the same age. Screening colonoscopy of these persons at risk between 40 and 50 years might be cost beneficial.

METHODS

We prepared a detailed cost-benefit analysis of screening colonoscopy and possible repeat endoscopies according to current expenditures for endoscopic procedures in Germany. Since screening colonoscopy is generally offered and reimbursed from 55 years on in Germany, we analysed the period between 45 and 55 years, taking an annual interest rate of 5% into account. Costs were analysed based on the results of a former study [11] depending on various participation rates in a general screening programme.

FINDINGS

Based on the available 1994 figure of about 20,000 euros for diagnosis and treatment of one cancer case, screening colonoscopy is cost beneficial when participation is high. Under a more realistic assumption of currently about 40,000 euros per cancer case, screening colonoscopy is cost beneficial in any case.

INTERPRETATION

Our data support that systematic screening colonoscopy in first-degree relatives of patients with CRC by the age of 45 years most likely demonstrates an economic benefit.

Polyp measurement using CT colonography: agreement with colonoscopy and effect of viewing conditions on interobserver and intraobserver agreement

OBJECTIVE

This article presents inter- and intraobserver agreement for estimates of polyp diameter using CT colonography, including the effects of different visualization displays and prior experience.

MATERIALS AND METHODS

Four observers, three of whom had prior experience with CT colonography, estimated the maximum diameter of 48 polyps using three different visualization displays: 2D colonography window, 2D abdominal window, and 3D surface rendering. Each re-measured a subset of 10 polyps. Polyps measured 2 to 12 mm according to a colonoscopic reference. Inter- and intraobserver agreement and agreement with the reference measurement were determined using the Bland-Altman method, paired Student's t testing, analysis of variance, and analysis of covariance (ANCOVA), and by calculating the components of variance.

RESULTS

CT measurements overestimated polyp diameter, a phenomenon found least using the 2D abdominal display. Generally, 95% limits of agreement encompassed different size categories for individual polyps: the widest spanned 14.6 mm (-4.6 mm to 10.0 mm) for an experienced observer using the 3D display. When using the 2D abdominal display, no significant difference was found between estimates and the reference value for the other two experienced observers (p = 0.83 and 0.23). All the observers' measurements were significantly different from the reference when using the 3D display (p < 0.001). The novice was significantly different from the experienced observers in some analyses. Inter- and intraobserver agreement were poorest for the 3D display.

CONCLUSION

Measurement of polyp diameter from CT colonography is subject to variation contingent on the observer's experience and the viewing display used. Although 3D visualization display is commonly used for polyp detection, it should not be used for measurement.

Incident rates of colonic neoplasia in older patients: when should we stop screening?

INTRODUCTION

Current guidelines endorse colon cancer screening every 5-10 years in patients over 50 years of age. However, there is no consensus regarding what age is appropriate to stop screening. The aim of this study was to characterize neoplasia occurrence/recurrence in a large cohort of patients > or =70 years of age undergoing colonoscopy.

METHODS

The Mayo Rochester endoscopic database was reviewed to determine the incidence of colonic neoplasia in patients > or =70 years undergoing two colonoscopies at least 12 months apart between January 1996 and December 2000. Patients were classified based on (i) age: 70-74, 75-79, > or =80 years; and (ii) polyp detection on initial examination, that is, subsequent examination for screening or surveillance.

RESULTS

Overall, 1353 patients underwent two colonoscopies at least 12 months apart (median interval 140 weeks) with removal of polyp on initial examination in 726 (53.7%) patients (surveillance cohort). On subsequent endoscopy, polyps > or =10 mm were detected in 54 (4.0%) and cancer in 13 (1.0%) patients. All age groups were well matched with respect to detection of neoplasia on index examination (P = 0.9) and polyp size on initial colonoscopy among the surveillance group (P = 0.9). Using a Cox proportional hazards model, adjusted hazard ratios (95% confidence interval [CI]) for neoplasia (polyps > or =10 mm) were: 2.0 (1.50-2.73, P < 0.0001) (surveillance vs screening), 1.33 (0.96-1.79, P = 0.08) (> or =80 vs 70-74), and 1.05 (0.78-1.38, P = 0.75) (75-79 vs 70-74). Adjusted hazard ratios for development of cancer were: 1.87 (1.03-3.97, P = 0.04) (surveillance vs screening), 1.73 (0.84-3.56, P = 0.13) (> or =80 vs 70-74), and 1.38 (0.71-2.77, P = 0.34) (75-79 vs 70-74).

CONCLUSIONS

Prior history of neoplasia remains a strong risk factor for colorectal neoplasia development in elderly patients and should be considered when deciding the need for continuing screening/surveillance. Incident neoplasia rates in a previously screened elderly population rise slowly with advancing age although cancer rates rise more sharply. Therefore, screening still retains a role in elderly patients; however, clinical judgment is still required to individualize screening practice. As the risk of competing comorbid illnesses continues to increase over time, the threshold to perform colon screening should increase accordingly.

Immunohistochemical expression of p16, p53, and p63 in colorectal adenomas and adenocarcinomas

PURPOSE

The aim of this study was to investigate the immunohistochemical expression of p16, p53, and p63 proteins according to some pathologic parameters related to colorectal adenomas and adenocarcinomas such as grade of dysplasia and histologic type.

METHODS

Immunohistochemistry with the antibodies p16, p53, and p63 was performed in tubular, tubular-villous, and villous adenomas (n = 30) and in well, moderately, and poorly differentiated adenocarcinomas (n = 30). The p63-positive cases were submitted to double immunolabeling with the cytokeratin 5 (CK5).

RESULTS

The p16 and p53 labelings were observed in some adenomas and adenocarcinomas but without any association with p63 expression, histologic type, or grade of differentiation of the neoplasm. P63 expression was found mainly in the villous adenomas and in the poorly differentiated adenocarcinomas. The poorly differentiated adenocarcinomas also exhibited coexpression of CK5 and p63.

CONCLUSIONS

Despite both p16 and p53 having been detected in colorectal neoplasms, they were not related to the different histologic variables nor to the expression of p63. However, p63 expression was closely associated with villous adenomas and poorly differentiated adenocarcinomas. Thus, p63 may represent a marker of poor differentiation in colorectal neoplasms. The coexpression of p63 and CK5 observed in this study could be related to divergent differentiation during the development of colorectal cancer, although further studies are warranted to refine the understanding of this process.