The National Polyp Study

A Multicenter Study of Colorectal Adenomas Rationale, Objectives, Methods and Characteristics of the Study Cohort

Background and Aims

The Multicenter Study of Colorectal Adenomas (SMAC) is a retrospective-prospective cohort study involving four Gastrointestinal Endoscopy Units in Italy. The main aim of the study is to evaluate the relationship between clinical and pathologic information at index colonoscopy and subsequent incidence of adenoma and colorectal carcinoma. We report the rationale, objectives and methods of the study, including patient characteristics at initial presentation.

Methods

All patients were consecutively identified from the endoscopy registries of the four Centres from January 1, 1985 to December 31, 1992. Inclusion criteria were: age 18-69 years, endoscopy performed with adequate toilette at least up to the rectosigmoid junction, and removal of all detectable polyps. Exclusion criteria were: familial adenomatous polyposis, inflammatory bowel diseases, adenocarcinoma in adenoma with infiltrated margins, previous invasive cancer at any site, colon resection and geographic inaccessibility.

Results

Out of 20,071 patients who underwent endoscopy at the four Centres, 11,959 fulfilled the eligibility criteria (5,892 males and 6,067 females, mean age = 51.1 ± 11.6 years). The main reasons for exclusion were age (n = 4,020) and previous or present colorectal cancer (n = 2,389). Symptoms were the most common reason for referral (72.3%), while post-polypectomy follow-up and positive fecal occult blood accounted for most of the remaining cases. A pancolonoscopy was performed in 3,088 patients (25.8%), while a left-sided endoscopy was performed in 7,887 (66%). A total number of 4,810 polyps were removed from 2,699 patients (2,994 adenomas, 1,580 hyperplastic polyps and 236 polyps lost after resection). A significant association (p < 0.001) between age and the endoscopic findings was observed. The subjects without polyps (n = 9,198) had the lowest age (mean = 49.9; 95%CL = 49.6 - 50.1) followed by the patients with hyperplastic polyps (n = 661; mean age = 52.3; 95%CL = 51.5-53.1), and the patients with adenomas (n = 1,732; mean age = 56.2; 95%CL = 55.8 - 56.6), and the patients with hyperplastic polyps and adenomas (n = 306; mean age = 57.2; 95%CL = 56.3 - 58.2). Polyps were diagnosed more frequently in males than in females (28.6% versus 17.0%; p < 0.0001).

Conclusion

This study provides some insights in the natural history of colorectal cancer and stresses the need to develop adequate strategies in the follow-up of subjects after either positive or negative colonoscopy.

Screening of colorectal cancer: present and future

Colorectal cancer (CRC) is the third most common cancer in males and second in females, and the fourth most common cause of cancer death worldwide. Currently, about 60-70% of diagnosed cases in symptomatic patients are detected at an advanced stage of disease. Earlier stage detection through the use of screening strategies would allow for better outcomes in terms of reducing the disease burden. Areas covered: The aim of this paper is to review the current published evidence from literature which assesses the performance and effectiveness of different screening tests for the early detection of CRC. Expert commentary: Adequate screening strategies can reduce CRC incidence and mortality. In the last few decades, several tests have been proposed for CRC screening. To date, there is still insufficient evidence to identify which approach is definitively superior, and no screening strategy for CRC can therefore be defined as universally ideal. The best strategy would be the one that can be economically viable and to which the patient can adhere best to over time. The latest guidelines suggest colonoscopy every 10 years or annual fecal immuno-chemical test (FIT) for people with normal risk, while for individuals with high risk or hereditary syndromes specific recommendations are provided.

Clinical impact of surveillance colonoscopy using magnification without diminutive polyp removal

BACKGROUND AND AIM

In Western countries, endoscopic removal of all adenomas during colonoscopy is recommended. The present study evaluates the usefulness of magnifying colonoscopy without removal of diminutive (≤5 mm) colorectal polyps.

METHODS

Patients with diminutive polyps who were observed for over 5 years using magnification at Hiroshima University Hospital were selected retrospectively. Lesions ≥6 mm in size, depressed lesions, and lesions with type V pit pattern were indications for endoscopic resection. We investigated the characteristics of lesions indicated for endoscopic resection detected on surveillance colonoscopy and the risk factors for the incidence of lesions indicated for endoscopic resection.

RESULTS

A total of 706 consecutive patients were enrolled. Sixty-eight lesions indicated for endoscopic resection were detected, averaging 9.0 ± 4.8 mm, and 33 (49%) lesions were located in the right colon. Pathological diagnoses were adenoma, Tis carcinoma, and T1 carcinoma in 58 (85%), eight (12%), and two (3%) lesions, respectively. Five lesions were considered to grow from previously detected diminutive polyps. Relative risks for the incidence of a lesion indicated for endoscopic resection were 1.76 (95% confidence interval [CI], 1.004-3.23) for males compared with females, 3.76 (95% CI, 2.03-7.50) for more than three polyps at initial colonoscopy compared with one polyp, and 2.84 (95% CI, 1.43-5.24) for patients with carcinoma at initial colonoscopy compared with patients with no lesion indicated for endoscopic resection. Nine carcinomas were resected endoscopically.

CONCLUSION

Diminutive low-grade adenomas detected by using magnifying colonoscopy may not necessarily require removal.

Comparison of Colonoscopy Surveillance Outcomes Between Young and Older Colorectal Cancer Patients

BACKGROUND

Young-onset colorectal cancer is uncommon, but the incidence is increasing. Despite several guidelines for colonoscopic surveillance following colorectal cancer resection, there is little consistency regarding the timing and age-adjusted strategies of surveillance colonoscopy after surgery of young-onset colorectal cancer. The aim of this study was to compare the outcomes of surveillance colonoscopy between sporadic colorectal cancer patients with young and older age after curative resection.

METHODS

We retrospectively reviewed 569 colorectal cancer patients who underwent curative resection between January 2006 and December 2010. The primary outcome was comparison of the development of metachronous advanced neoplasia during surveillance colonoscopy between young and older colorectal cancer patients.

RESULTS

There were 95 patients in the young age group and 474 patients in the older age group. The mean time interval from surgery to the development of metachronous advanced neoplasia was 99.2 ± 3.7 months in the young age group and 84.4 ± 2.5 months in the old age group (P = 0.03). In the multivariate analysis, age (OR, 3.56; P = 0.04) and family history of colorectal cancer (OR, 2.66; P = 0.008) were associated with the development of metachronous advanced neoplasia. None of the young patients without both family history of colorectal cancer and high-risk findings at index colonoscopy showed advanced neoplasia during the follow-up period.

CONCLUSIONS

Age and family history of colorectal cancer are independent risk factors for the occurrence of advanced neoplasia after curative colorectal cancer resection, suggesting age-adjusted strategies of surveillance colonoscopy.

A large proportion of fecal immunochemical test-positive participants in colorectal cancer screening is symptomatic

Background

Symptomatic invitees are advised not to participate in colorectal cancer (CRC) screening but to directly consult their general practitioner (GP), because fecal immunochemical test (FIT) sensitivity for cancer is not optimal. This recommendation may not always be followed in daily practice. We evaluated how many FIT-positive participants had CRC-related symptoms and whether the presence of symptoms was associated with the presence and location of CRC/advanced neoplasia.

Methods

We prospectively collected data on CRC-related symptoms in all FIT-positive participants in the Dutch CRC screening program, referred to our endoscopy centers between 2014 and 2016, and evaluated whether symptoms were associated with detected CRC/advanced neoplasia at colonoscopy.

Results

Of 527 FIT-positive participants, 314 had advanced neoplasia, of which 41 had CRC. Overall, 246 (47%; 95% confidence interval (CI) 0.42–0.51) reported CRC-related symptoms. A change in bowel habits (odds ratio (OR) 2.86, CI 1.23–6.62) and visible blood in stool (OR 8.65, CI 2.34–32.0) were associated with the detection of CRC at colonoscopy. We did not observe significant associations between evaluated symptoms and advanced neoplasia.

Conclusions

A large proportion of FIT-positive screening participants have CRC-related symptoms. This suggests that current instructions do not retain symptomatic screening invitees from participation and awareness of CRC-related symptoms is inadequate.

The Diagnostic Yield of Colonoscopy Stratified by Indications

Introduction

Danish centers reserve longer time for screening colonoscopies and allocate the most experienced endoscopists to these cases. The objective of this study is to determine the diagnostic yield in colonoscopies for different indications to improve planning of colonoscopy activity and allocation of the highly skilled endoscopists.

Methods

Nine hundred and ninety-nine randomly collected patients from a prospectively maintained database were grouped in defined referral indication groups. Five groups were compared in respect of the detection rate of adenomas and cancers.

Results

Two hundred and eighty-nine of 1098 colonoscopies in 999 patients showed significant neoplastic findings, resulting in 591 adenoma resections. Eighty-five percent were treated with a snare resection, and 15% with endoscopic mucosa resection (EMR). Positive findings in the indication groups were (1) symptoms, 25%; (2) positive screening, 17%; (3) previous resection of adenomas, 45%; (4) previous resection of colorectal cancer, 15%; and (5) surveillance of patients with high-risk family history of cancer, 35%.

Conclusion

The majority of adenomas found during colonoscopy can be treated with simple techniques. If individualized time slots are considered, the adenoma follow-up colonoscopies are likely to be the most time-consuming group with more than twice the number of adenomas detected as compared to other indications.

New insights into the earliest stages of colorectal tumorigenesis

Tumors in the large intestine have been postulated to arise via a stepwise accumulation of mutations, a process that takes up to 20 years. Recent advances in lineage tracing and DNA sequencing, however, are revealing new evolutionary models that better explain the vast amount of heterogeneity observed within and across colorectal tumors. Areas covered: A review of the literature supporting a novel model of colorectal tumor evolution was conducted. The following commentary examines the basic science and clinical evidence supporting a modified view of tumor initiation and progression in the colon. Expert commentary: The proposed 'cancer punctuated equilibrium' model of tumor evolution better explains the variability seen within and across polyps of the colon and rectum. Small colorectal polyps (6-9mm) followed longitudinally by interval imaging with CT colonography have been reported to have multiple fates: some growing, some remaining static in size, and others regressing in size over time. This new model allows for this variability in growth behavior and supports the hypothesis that some tumors can be 'born to be bad' as originally postulated by Sottoriva and colleagues, with very early molecular events impacting tumor fitness and growth behavior in the later stages of the disease process.

Local Recurrence and Its Risk Factor after Incomplete Resection of Colorectal Advanced Adenomas: A Single Center, Retrospective Study

Background/Aims

Colonoscopy can detect precancerous lesions, which can subsequently be removed and reduce incidences of and mortality from colorectal cancer (CRC). However, recently published data have highlighted a significant rate of CRC in patients who previously underwent colonoscopy. Among many reasons, incomplete resection has been considered as a significant contributor. However, to date, there have only been a few studies regarding incompletely resected polyps, especially advanced colorectal adenoma (ACA). Hence, we aimed to evaluate the prognosis of incompletely resected ACA.

Methods

We retrospectively reviewed the medical records of patients with ACA who had underwent endoscopic treatment with incomplete resection. The primary outcomes were (1) the incomplete resection rate of ACA, as determined by a histopathologic examination and (2) the recurrence rate of incompletely resected ACA. We also investigated the probable contributing factors that may have led to a relapse of incompletely resected ACA.

Results

A total of 7,105 patients had their colorectal polyps resected by endoscopic treatment, and 2,233 of these were considered as ACA. Of these, 354 polyps (15.8%) were resected incompletely, and only 163 patients were followed-up. Of those followed-up, 31 patients (19.0%) experienced local recurrence. The risk factors for recurrence after incomplete resection were evaluated; age, morphology of adenoma, and use of rescue therapy, such as argon plasma coagulation, were found to be associated with adenoma recurrence.

Conclusions

Incompletely resected ACA in older patients or in patients with sessile-type adenomas should be monitored strictly, and if incomplete resection is suspected, rescue therapy must be considered.

McKittrick Wheelock Syndrome Treated by Transanal Minimally Invasive Surgery: A Single-Center Experience and Review of the Literature

INTRODUCTION

McKittrick Wheelock Syndrome (MKWS) is a rare syndrome characterized by secretory diarrhea, dehydration, prerenal acute kidney injury, and severe electrolyte abnormalities caused by a large hypersecretory villous adenoma located in the rectum or rectosigmoid junction. Transabdominal (laparoscopic) procedures are the most described procedures in the treatment of MKWS. We report an alternative surgical approach, transanal minimally invasive surgery (TAMIS), to solve this syndrome.

MATERIALS AND METHODS

All patients who underwent transanal endoscopic microsurgery or TAMIS were included in a prospectively collected database in our center. Between 1996 and 2015, 3 patients were found to have MKWS and treated by TAMIS. Demographics, characteristics of the adenoma, surgery-related data, and outcome were analyzed.

RESULTS

The first patient had a villous adenoma 0-12 cm from the anal verge. After TAMIS, she complained of a stenosis that was successfully treated by dilatation. The second patient had an impressive bulky tumor in the rectum. An endoscopic mucosal resection was attempted twice, but incompletely. Pathology analysis showed villous adenoma with high-grade dysplasia and intramucosal carcinoma. One year after TAMIS, a recurrence was detected and treated by an abdominal-perineal resection. A TAMIS was performed in the third patient because of a giant villous circular adenoma, but because of high mucus and fluid production, no proper overview could be obtained. Together with opening of the peritoneum, this prompted us to convert to a laparoscopic Hartmann procedure. Besides this technical difficulty, the patient recovered uneventful.

CONCLUSIONS

MKWS is a rare syndrome and missed diagnosis could result in life-threatening situations. Different endoscopic and surgical treatments are described to solve this syndrome. TAMIS should be considered as a rectum-preserving surgical treatment option for such extensive adenomas.

Changing Paradigms in Detection of Dysplasia and Management of Patients With Inflammatory Bowel Disease: Is Colectomy Still Necessary?

This review chronicles the evolution of dysplasia detection and management in inflammatory bowel disease since 1925, the year the first case report of colitis-related colorectal cancer was published. We conclude that colorectal cancer prevention and dysplasia management for patients with inflammatory bowel disease has changed since this first case report, from somewhat hopeless to hopeful.

The association between location, age and advanced colorectal adenoma characteristics: a propensity-matched analysis

PURPOSE

Evidence supports an association between certain colorectal adenoma characteristics and predisposition to cancer. The association between anatomical location of colorectal adenoma, age and advanced adenomas needs attention. The objective of this study was to evaluate the possible association between occurrence of sporadic advanced adenomas with location and age.

MATERIALS AND METHODS

A cross-sectional study using baseline data from index colonoscopy from a randomized controlled trial evaluating chemopreventive treatment against recurrence of colorectal adenomas was performed. Inclusion criteria for patients were one adenoma of >1 cm in diameter or multiple adenomas of any size, or an adenoma of any size and familial disposition for colorectal cancer. Multivariate regression and propensity score-matched analyses were used to correlate location of adenomas and age with advanced adenoma features.

RESULTS

In this study, 2149 adenomas were removed in 1215 patients. Advanced colorectal adenomas primarily occurred in the anal part of the colon. Older age was associated with more adenomas and more oral occurrence of adenomas, as well as a higher risk of advanced adenomas. Surprisingly, specifically for the oral adenomas the risk of advanced adenoma seems to be lower for older patients compared with younger.

CONCLUSIONS

This study presents new results with regard to association between age, location of adenomas and risk of advanced adenomas. The results indicate that sigmoidoscopy for screening purposes may be obsolete, and add to the existing literature on which future guidelines for screening may be based.

Three-dimensional computed tomography rendering of pedunculated colon polyp: new "clapper-bell" sign pedunculated polyp at 3D computed tomography

The incidental detection of a tubulovillous adenoma at a contrast-enhanced computed tomography (CECT) with nondedicated protocol, performed in emergency conditions, is an uncommon finding. We report a case of a woman presenting with a subocclusive episode. A CECT scan was performed, and a pedunculated polyp could be appreciated at 3D-reconstruction images. A particular depiction of pedunculus of the polypoid lesion, resemble a clapper-bell, could help to define the vegetating lesion at the volume-rendering reconstruction images. This case emphasizes the fundamental role of postprocessing in the clinical practice to improve the diagnostic accuracy of abdominal CT scan. In addition, a potential new radiologic sign, the "clapper-bell sign", is proposed, as literature about the appearance of a polyp at CECT, performed without a dedicated protocol for colonoscopy, is poor.

Comparison of biomarker expression between proximal and distal colorectal adenomas: The Tennessee-Indiana Adenoma Recurrence Study

It is unclear if proximal and distal traditional adenomas present with differences in molecular events which contribute to cancer heterogeneity by tumor anatomical subsite. Participants from a colonoscopy-based study (n = 380) were divided into subgroups based on the location of their most advanced adenoma: proximal, distal, or "equivalent both sides." Eight biomarkers in the most advanced adenomas were evaluated by immunohistochemistry (Ki-67, COX-2, TGFβRII, EGFR, β-catenin, cyclin D1, c-Myc) or TUNEL (apoptosis). After an adjustment for pathological features, there were no significant differences between proximal and distal adenomas for any biomarker. Conversely, expression levels did vary by other features, such as their size, villous component, and synchronousness. Large adenomas had higher expression levels of Ki-67(P < 0.001), TGFβRII (P < 0.0001), c-Myc (P < 0.001), and cyclin D1 (P < 0.001) in comparison to small adenomas, and tubulovillous/villous adenomas also were more likely to have similar higher expression levels in comparison to tubular adenomas. Adenoma location is not a major determinant of the expression of these biomarkers outside of other pathological features. This study suggests similarly important roles of Wnt/β-catenin and TGF-β pathways in carcinogenesis in both the proximal and distal colorectum. © 2016 Wiley Periodicals, Inc.

A comparison of endoscopy versus pathology sizing of colorectal adenomas and potential implications for surveillance colonoscopy

BACKGROUND AND AIMS

The aim of this study was to compare endoscopy and pathology sizing in a large population-based series of colorectal adenomas and to evaluate the implications for patient stratification into surveillance colonoscopy.

METHODS

Endoscopy and pathology sizes available from intact adenomas removed at colonoscopies performed as part of the Northern Ireland Bowel Cancer Screening Programme, from 2010 to 2015, were included in this study. Chi-squared tests were applied to compare size categories in relation to clinicopathologic parameters and colonoscopy surveillance strata according to current American Gastroenterology Association and British Society of Gastroenterology guidelines.

RESULTS

A total of 2521 adenomas from 1467 individuals were included. There was a trend toward larger endoscopy than pathology sizing in 4 of the 5 study centers, but overall sizing concordance was good. Significantly greater clustering with sizing to the nearest 5 mm was evident in endoscopy versus pathology sizing (30% vs 19%, P < .001), which may result in lower accuracy. Applying a 10-mm cut-off relevant to guidelines on risk stratification, 7.3% of all adenomas and 28.3% of those 8 to 12 mm in size had discordant endoscopy and pathology size categorization. Depending on which guidelines are applied, 4.8% to 9.1% of individuals had differing risk stratification for surveillance recommendations, with the use of pathology sizing resulting in marginally fewer recommended surveillance colonoscopies.

CONCLUSIONS

Choice of pathology or endoscopy approaches to determine adenoma size will potentially influence surveillance colonoscopy follow-up in 4.8% to 9.1% of individuals. Pathology sizing appears more accurate than endoscopy sizing, and preferential use of pathology size would result in a small, but clinically important, decreased burden on surveillance colonoscopy demand. Careful endoscopy sizing is required for adenomas removed piecemeal.

Does Cancer Risk in Colonic Polyps Unsuitable for Polypectomy Support the Need for Advanced Endoscopic Resections?

BACKGROUND

There is a continuing debate on the best approach for endoscopically benign large polyps that are unsuitable for conventional endoscopic resection. This study aimed to estimate the cancer risk in patients with endoscopically benign unresectable colonic polyps referred for surgery.

STUDY DESIGN

We assessed patients with an endoscopic diagnosis of benign adenoma deemed not amenable to endoscopic removal, who underwent colectomy between 1997 and 2012. Patients with preoperative diagnoses of cancer, inherited polyposis syndrome, inflammatory bowel disease, and synchronous pathology requiring surgery were excluded.

RESULTS

There were 439 patients (220 [50.1%] men; median age 67 years [range 27 to 97 years]) who underwent colectomy. Of 439 patients, 346 (79%) underwent preoperative endoscopy at our institution. Most of the polyps were located in the right colon (394 of 439, 89.7%), with the majority in the cecum (199 of 394, 45.3%). Polyp morphology was as follows: sessile (n = 252, 57.4%), pedunculated (n = 109, 24.8%), and flat (n = 78, 17.8%). Endoscopic pathology revealed high-grade dysplasia in 88 (20%) patients. Mean colonoscopic and postoperative polyp sizes were 3.0 cm (range 0.3 to 10 cm) and 2.7 cm (range 0 to 11 cm), respectively (p < 0.001). Final surgical pathology revealed cancer in 37 patients (8%). Polyp location, morphology, and histologic types were similar between the benign and malignant polyps. Cancer stages were: stage I (23 patients), stage II (11 patients), and stage III (3 patients).

CONCLUSIONS

For the majority of endoscopically benign colonic polyps, an oncologic colonic resection may be unnecessary, so advanced endoscopic resection techniques or laparoscopic-assisted polypectomy should be considered. When bowel resection is needed, the resection should be performed, obeying oncologic principles and techniques.

Chromoscopy versus conventional endoscopy for the detection of polyps in the colon and rectum

BACKGROUND

Although conventional colonoscopy is the most accurate test available for the investigation of the colorectum for polyps, data exist that raise concerns about its sensitivity. Chromoscopy (spraying dye onto the surface of the colon to make polyps more visible) may be one way of enhancing the ability of colonoscopy to detect polyps, particularly diminutive flat lesions, which otherwise may be difficult to detect.

OBJECTIVES

To determine whether the use of chromoscopy enhances the detection of polyps and neoplasia during endoscopic examination of the colon and rectum.

SEARCH METHODS

We searched the following databases: Cochrane Colorectal Cancer Group Specialised Register (October 2015), Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library; Issue 10, 2015), MEDLINE (January 1950 to October 2015), EMBASE (January 1974 to October 2015), and ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (both November 2015). We also handsearched abstracts from relevant meetings from 1980 to 2015. Search terms included 'randomised trials' containing combinations of the following: 'chromoscopy' 'colonoscopy' 'dye-spray' 'chromo-endoscopy' 'indigo-carmine' 'magnifying endoscopy'.

SELECTION CRITERIA

We included all prospective randomised trials comparing chromoscopic with conventional endoscopic examination of the whole of the colon and rectum. We excluded studies of people with inflammatory bowel disease or polyposis syndromes and any studies that combined chromoscopy with additional interventions (cap assistance, water-perfused, etc.).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodological quality of potentially eligible trials, and two review authors independently extracted data from the included trials. Outcome measures included the detection of polyps (neoplastic and non-neoplastic), the detection of diminutive lesions, the number of participants with multiple neoplastic lesions, and the extubation time.

MAIN RESULTS

We included seven trials (2727 participants) in this update. Five trials were of sufficiently similar design to allow for pooled results. Two trials differed substantially in design and were included in a subgroup analysis. All the trials had some methodological drawbacks. However, combining the results showed a significant difference in favour of chromoscopy for all detection outcomes. In particular, chromoscopy was likely to yield significantly more people with at least one neoplastic lesion (odds ratio (OR) 1.53, 95% confidence interval (CI) 1.31 to 1.79; 7 trials; 2727 participants), and at least one diminutive neoplastic lesion (OR 1.51, 95% CI 1.19 to 1.92; 4 trials; 1757 participants). Significantly more people with three or more neoplastic lesions were also detected, but only when studies that used high-definition colonoscopy in the control group were excluded (OR 4.63, 95% CI 1.99 to 10.80; 2 trials; 519 participants). None of the included studies reported any adverse events related to the use of the contrast dye.

AUTHORS' CONCLUSIONS

There is strong evidence that chromoscopy enhances the detection of neoplasia in the colon and rectum. People with neoplastic polyps, particularly those with multiple polyps, are at increased risk of developing colorectal cancer. Such lesions, which presumably would be missed with conventional colonoscopy, could contribute to the interval cancer numbers on any surveillance programme.

Screening for Colorectal Cancer Using a Multitarget Stool DNA Test: Modeling the Effect of the Intertest Interval on Clinical Effectiveness

BACKGROUND

A multitarget stool DNA (mt-sDNA) test was recently approved for colorectal cancer (CRC) screening for men and women, aged ≥ 50 years, at average risk of CRC. The guidelines currently recommend a 3-year interval for mt-sDNA testing in the absence of empirical data. We used clinical effectiveness modeling to project decreases in CRC incidence and related mortality associated with mt-sDNA screening to help inform interval setting.

MATERIALS AND METHODS

The Archimedes model (Archimedes Inc., San Francisco, CA) was used to conduct a 5-arm, virtual, clinical screening study of a population of 200,000 virtual individuals to compare the clinical effectiveness of mt-sDNA screening at 1-, 3-, and 5-year intervals compared with colonoscopy at 10-year intervals and no screening for a 30-year period. The study endpoints were the decrease in CRC incidence and related mortality of each strategy versus no screening. Cost-effectiveness ratios (US dollars per quality-adjusted life year [QALY]) of mt-sDNA intervals were calculated versus no screening.

RESULTS

Compared with 10-year colonoscopy, annual mt-sDNA testing produced similar reductions in CRC incidence (65% vs. 63%) and related mortality (73% vs. 72%). mt-sDNA testing at 3-year intervals reduced the CRC incidence by 57% and CRC mortality by 67%, and mt-sDNA testing at 5-year intervals reduced the CRC incidence by 52% and CRC mortality by 62%. At an average price of $600 per test, the annual, 3-year, and 5-year mt-sDNA screening costs would be $20,178, $11,313, and $7388 per QALY, respectively, compared with no screening.

CONCLUSION

These data suggest that screening every 3 years using a multitarget mt-sDNA test provides reasonable performance at acceptable cost.

Rate and Risk Factors of the Advanced Adenomas Among Diminutive Colorectal Polyps

Only 49 % of diminutive colorectal polyps are neoplastic, but a tiny percentage contains advanced histology. We aimed to determine the rate of advanced diminutive polyps and to evaluate the influence of age, gender, number, and localization. Patients undergoing a videocolonoscopy in October 2010 and April 2012 were collected prospectively. Subjects with polyps ≤5 mm in diameter were recruited into the study. The presence of a villous component of >25 % and a high degree of dysplasia were categorized as polyps with advanced histology. Two hundred eight diminutive polyps were identified in 102 patients. Twenty (9.6 %) diminutive polyps in 13 (12.74 %) patients showed advanced histology. The probability of having an advanced diminutive polyp was higher in patients who have more than one polyp or have polyps localized all along the colon or only to the distal part (p < 0.001 and p = 0.002). Having more than one polyp increases the likelihood of having advanced diminutive polyp according to a multivariate analysis (p = 0.003). Polyps accompanying any dysplastic diminutive polyp, being one of multiple polyps, and distributed all along the colon or localized to only the distal part have an increased probability of being an advanced diminutive polyp (p < 0.001, p = 0.047, p < 0.001, and p = 0.008). Multivariate logistic regression demonstrated that only any accompanying dysplastic diminutive polyp increases the probability of a polyp being advanced diminutive (p = 0.034). Diminutive polyps could have advanced histology. Multiple polyps located in the whole colorectum or to the distal part or accompanying any advanced polyps may harbor an advanced histology and should be removed.

Poorly Differentiated Neuroendocrine Tumor of the Rectum Coexistent with Giant Rectal Villous Adenoma Presenting as McKittrick-Wheelock Syndrome

McKittrick-Wheelock Syndrome is a rare disorder, noted for electrolyte and fluid depletion caused by secretory colorectal adenomas and carcinomas. We report here the first reported case of a 55-year-old man with a large rectal villous adenoma coexistent with a poorly differentiated neuroendocrine tumor of rectum presenting with McKittrick-Wheelock Syndrome. Palliative chemotherapy resulted in complete resolution of symptoms and improved quality of life.

High-definition endoscopy with digital chromoendoscopy for histologic prediction of distal colorectal polyps

BACKGROUND

Distal diminutive colorectal polyps are common and accurate endoscopic prediction of hyperplastic or adenomatous polyp histology could reduce procedural time, costs and potential risks associated with the resection. Within this study we assessed whether digital chromoendoscopy can accurately predict the histology of distal diminutive colorectal polyps according to the ASGE PIVI statement.

METHODS

In this prospective cohort study, 224 consecutive patients undergoing screening or surveillance colonoscopy were included. Real time histology of 121 diminutive distal colorectal polyps was evaluated using high-definition endoscopy with digital chromoendoscopy and the accuracy of predicting histology with digital chromoendoscopy was assessed.

RESULTS

The overall accuracy of digital chromoendoscopy for prediction of adenomatous polyp histology was 90.1 %. Sensitivity, specificity, positive and negative predictive values were 93.3, 88.7, 88.7, and 93.2 %, respectively. In high-confidence predictions, the accuracy increased to 96.3 % while sensitivity, specificity, positive and negative predictive values were calculated as 98.1, 94.4, 94.5, and 98.1 %, respectively. Surveillance intervals with digital chromoendoscopy were correctly predicted with >90 % accuracy.

CONCLUSIONS

High-definition endoscopy in combination with digital chromoendoscopy allowed real-time in vivo prediction of distal colorectal polyp histology and is accurate enough to leave distal colorectal polyps in place without resection or to resect and discard them without pathologic assessment. This approach has the potential to reduce costs and risks associated with the redundant removal of diminutive colorectal polyps.

TRIAL REGISTRATION

ClinicalTrials NCT02217449.

Evaluation of pro-inflammatory markers plasma C-reactive protein and urinary prostaglandin-E2 metabolite in colorectal adenoma risk

C-reactive protein (CRP) is a pro-inflammatory protein with potential as a biomarker in predicting colon cancer risk. However, little is known regarding its association with risk of colorectal adenomas, particularly by subtypes. We conducted a colonoscopy-based matched case-control study to assess whether elevated plasma CRP levels may be associated with colorectal adenoma risk and further whether this association may be modified by urinary prostaglandin E2 metabolite (PGE-M), a biomarker of systemic prostaglandin E2 production. Included in the study were 226 cases with a single small tubular adenoma, 198 cases with multiple small tubular adenomas, 283 cases with at least one advanced adenoma, and 395 polyp-free controls. No apparent association between CRP level and risk of single small tubular adenomas was found (ptrend  = 0.59). A dose-response relationship with CRP level was observed for risk of either multiple small tubular adenomas (OR = 2.01, 95%CI = 1.10-3.68 for the highest versus lowest tertile comparison; ptrend   = 0.03) or advanced adenomas (OR = 1.81, 95%CI = 1.10-2.96 for the highest versus lowest tertile comparison; ptrend  = 0.02). In a joint analysis of CRP level and PGE-M, risk of multiple or advanced adenoma was greatest among those with highest levels of both CRP and PGE-M in comparison to those with low CRP and low PGE-M (OR = 3.72, 95%CI = 1.49-9.72). Our results suggest that elevated CRP, particularly in the context of concurrent elevated PGE-M, may be a biomarker of multiple or advanced adenoma risk in a screening age population. © 2015 Wiley Periodicals, Inc.

Prevalence and characteristics of colorectal polyps in symptomatic and asymptomatic Iranian patients undergoing colonoscopy from 2009-2013

BACKGROUND

Colorectal cancer is the third most common type of cancer in males and the second in females in Iran. Males are more likely to develop CRC than women and age is considered as a main risk factor for colorectal cancer. Prevalence of colorectal cancer has been increasing in Asian countries.

AIM

The object of this study was to determine the clinical and pathology characteristics of colorectal polyps in Iranian patients and to investigate the variation between our populations with other populations.

MATERIALS AND METHODS

A total of 167 patients with colorectal polyps were included in our study. All underwent colonoscopy during 2009-2013 and specimens were taken through polypectomy and transferred to pathology. All data in patient files including pathology reports were collected and analyzed by SPSS 16 software. A two-tailed test was used and a P-value of <0.05 was considered significant.

RESULTS

Mean age of participants was 57±15. Some 84 were females (50.3%) and 83 males (49.7%). Total of 225 polyps were detected which 119 (52.9%) were in males and 106 (47.1%) were in females. Solitary polyps were observed in 124 patients (74%), 26 (15.6%) had two polyps and 17 (10.1%) with more than two polyps (three to five). Rectosigmoid was the site of most of the polyps (63.1%), followed by 19.6% in the descending colon, 7.6% in the transverse, 5.8% in the ascending, and 3.1% in the cecum, data being missing in two cases.

CONCLUSIONS

Recto sigmoid was site of most of the polyps. The most prevalent type of lesion was adenomatous polyps detected in 78 (34.7%). Mixed hyperplastic adenomatous type observed in 70 (31.1%). This high prevalence of adenomatous polyps in Iranian patients implies the urgent need for screening plans to prevent further healthcare problems with colorectal cancer in the Iranian population.

Molecular biomarkers in colorectal carcinoma

Colorectal cancer is a tumor with increasing incidence which represents one of the first leading causes of death worldwide. Gene alterations described for colorectal cancer include genome instability (microsatellite and chromosomal instability), CpG islands methylator phenotype, microRNA, histone modification, protein biomarkers, gene mutations (RAS, BRAF, PI3K, TP53, PTEN) and polymorphisms (APC, CTNNB1, DCC). In this article, biomarkers with prognostic value commonly found in colorectal cancer will be reviewed.

The role of virtual colonoscopy in colorectal screening

Colorectal cancer is the second leading cause of cancer-related deaths in the United States. The earlier colorectal cancer is detected, the better chance a person has of surviving 5 years after being diagnosed, emphasizing the need for effective and regular colorectal screening. Computed tomographic colonography has repeatedly demonstrated sensitivities equivalent to the current gold standard, optical colonoscopy, in the detection of clinically relevant polyps. It is an accurate, safe, affordable, available, reproducible, quick, and cost-effective option for colorectal screening and should be considered for mass screening.

New paradigms in polypectomy: resect and discard, diagnose and disregard

Polypectomy at colonoscopy has been shown to reduce the subsequent risk of colorectal cancer. With the advent of national screening programs, the number of colonoscopies performed has increased worldwide. In addition, the recent drive for quality improvement combined with advances in colonoscopic technology has resulted in increased numbers of polyps detected, resected, and sent for histopathology leading to spiraling costs associated with the procedure. Being able to diagnose small polyps in vivo (optical diagnosis) would allow for adenomas to be resected and discarded without the need to retrieve them or send them for formal histopathology.

ASGE Technology Committee systematic review and meta-analysis assessing the ASGE PIVI thresholds for adopting real-time endoscopic assessment of the histology of diminutive colorectal polyps

In vivo real-time assessment of the histology of diminutive (≤5 mm) colorectal polyps detected at colonoscopy can be achieved by means of an "optical biopsy" by using currently available endoscopic technologies. This systematic review and meta-analysis was performed by the American Society for Gastrointestinal Endoscopy (ASGE) Technology Committee to specifically assess whether acceptable performance thresholds outlined by an ASGE Preservation and Incorporation of Valuable endoscopic Innovations (PIVI) document for clinical adoption of these technologies have been met. We conducted direct meta-analyses calculating the pooled negative predictive value (NPV) for narrow-band imaging (NBI), i-SCAN, and Fujinon Intelligent Color Enhancement (FICE)-assisted optical biopsy for predicting adenomatous polyp histology of small/diminutive colorectal polyps. We also calculated the pooled percentage agreement with histopathology when assigning postpolypectomy surveillance intervals based on combining real-time optical biopsy of colorectal polyps 5 mm or smaller with histopathologic assessment of polyps larger than 5 mm. Random-effects meta-analysis models were used. Statistical heterogeneity was evaluated by means of I(2) statistics. Our meta-analyses indicate that optical biopsy with NBI, exceeds the NPV threshold for adenomatous polyp histology, supporting a "diagnose-and-leave" strategy for diminutive predicted nonneoplastic polyps in the rectosigmoid colon. The pooled NPV of NBI for adenomatous polyp histology by using the random-effects model was 91% (95% confidence interval [CI], 88-94). This finding was associated with a high degree of heterogeneity (I(2) = 89%). Subgroup analysis indicated that the pooled NPV was greater than 90% for academic medical centers (91.8%; 95% CI, 89-94), for experts (93%; 95% CI, 91-96), and when the optical biopsy assessment was made with high confidence (93%; 95% CI, 90-96). Our meta-analyses also indicate that the agreement in assignment of postpolypectomy surveillance intervals based on optical biopsy with NBI of diminutive colorectal polyps is 90% or greater in academic settings (91%; 95% CI, 86-95), with experienced endoscopists (92%; 95% CI, 88-96) and when optical biopsy assessments are made with high confidence (91%; 95% CI, 88-95). Our systematic review and meta-analysis confirms that the thresholds established by the ASGE PIVI for real-time endoscopic assessment of the histology of diminutive polyps have been met, at least with NBI optical biopsy, with endoscopists who are expert in using this advanced imaging technology and when assessments are made with high confidence.

The history of colorectal cancer screening: a personal perspective

The present explosive interest in screening for colorectal cancer (CRC), one of the most prevalent and preventable cancers, had its beginnings at a hospital in London and an Internist's office in Ohio. Demonstrated there were the concepts that CRC did not occur de-novo but arose from a premalignant polyp, that detection of the resultant cancer at an earlier stage was associated with better survival and that cancer could be detected at an early presymptomatic stage by screening. Many years later, the introduction of colonoscopy and colonoscopic polypectomy provided the opportunity for randomized trials to prove that these concepts were true. The sequence of rigorous science followed by guidelines consensus and then multilevel national efforts of screening implementation has resulted in a decline in the CRC incidence and mortality worldwide, most significantly in the USA. Campaigns have been initiated to maximize population screening and further investigate its optimal approach. Some historical details of this success story and many of the key participants are presented in this paper.

What are the Endoscopic and Pathological Characteristics of Colorectal Polyps?

BACKGROUND

Colon polyps need to be excised upon detection during colonoscopy due to the risk of malignancy irrespective of their size. In our study, we retrospectively evaluated the clinicopathological characteristics of polyps detected during colonoscopy.

MATERIALS AND METHODS

We assessed 379 patients with polyps detected during colonoscopy between January 2010 and May 2012. The demographics, complaints, colonoscopy findings (shape, place and size of the polyp) and histopathological findings were recorded. We carried out statistical analysis using PASW 18.0 for Windows.

RESULTS

There were 227 males (59.9%) and 152 females (40.1%) in the trial. The mean age was 53.8 years (32-90). The most common complaint was rectal bleeding (36.1%), followed by abdominal pain (35.4%). Polyps were detected most commonly in the rectosigmoid region (43.8%), followed by the descending colon (17.4%). Some 239 patients had a single polyp (63.1%) while 140 were found to have multiple polyps (36.9%). While tubular adenoma was the most common pathological type, occurring in 181 patients (47.8%), tubulovillous adenoma (14.2%) and hyperplastic polyp (12.7%) followed, occurring in 54 and 48 patients respectively. While 313 patients (82.6%) did not feature dysplasia, 37 patients (9.7%) exhibited low- grade dysplasia, 28 (7.7%) had high-grade dysplasia and 4 had cancer (1.1%). The rates of villous components and dysplasia were detected to be high among pedunculated polyps and polyps larger than 1 cm (p<0.001).

CONCLUSIONS

Due to the fact that large-diameter polyps with malignant potential are commonly located in the left colon and have a high prevalence among the middle-aged individuals, it would be appropriate to screen this population at regular intervals via rectosigmoidoscopy.

Paleolithic and Mediterranean diet pattern scores and risk of incident, sporadic colorectal adenomas

The Western dietary pattern is associated with higher risk of colorectal neoplasms. Evolutionary discordance could explain this association. We investigated associations of scores for 2 proposed diet patterns, the "Paleolithic" and the Mediterranean, with incident, sporadic colorectal adenomas in a case-control study of colorectal polyps conducted in Minnesota (1991-1994). Persons with no prior history of colorectal neoplasms completed comprehensive questionnaires prior to elective, outpatient endoscopy; of these individuals, 564 were identified as cases and 1,202 as endoscopy-negative controls. An additional group of community controls frequency-matched on age and sex (n = 535) was also recruited. Both diet scores were calculated for each participant and categorized into quintiles, and associations were estimated using unconditional logistic regression. The multivariable-adjusted odds ratios comparing persons in the highest quintiles of the Paleolithic and Mediterranean diet scores relative to the lowest quintiles were, respectively, 0.71 (95% confidence interval (CI): 0.50, 1.02; Ptrend = 0.02) and 0.74 (95% CI: 0.54, 1.03; Ptrend = 0.05) when comparing cases with endoscopy-negative controls and 0.84 (95% CI: 0.56, 1.26; Ptrend = 0.14) and 0.77 (95% CI: 0.53, 1.11; Ptrend = 0.13) when comparing cases with community controls. These findings suggest that greater adherence to the Paleolithic diet pattern and greater adherence to the Mediterranean diet pattern may be similarly associated with lower risk of incident, sporadic colorectal adenomas.

Colorectal serrated pathway cancers and precursors

The serrated pathway (SP) can be viewed as two parallel, but partially overlapping, arrays of colorectal precursor lesions, and their respective endpoint carcinomas, that are distinct from those of the conventional adenoma-carcinoma sequence (APC-pathway). In this review we focus at the outset on the clinical impact, pathological features, molecular genetics and biological behaviours of the various SP cancers. Then we summarize the clinicopathological features, classification and molecular profiles of the two main precursor lesions that anchor the respective pathways: (i) sessile serrated adenoma/polyp (SSA/P), also called sessile serrated lesion (SSL), and (ii) traditional serrated adenoma (TSA). Activating mutations of the RAS-RAF-MAPK pathway initiate and sustain the lesions of the SP, and CpG island methylation of the promoter regions of tumour suppressor and DNA repair genes play the major role in their neoplastic progression. The SP includes microsatellite stable (MSS) carcinomas that are among the most biologically aggressive colorectal carcinomas (CRC), and also accounts for the great preponderance of sporadic hypermutated, mismatch repair (MMR)-deficient or microsatellite instable (MSI) CRC. The identification, removal and appropriate classification of at-risk SP precursors and surveillance of individuals who harbour these lesions present a challenge and opportunity for CRC prevention and mortality reduction.

Clinicopathological differences of laterally spreading tumors arising in the colon and rectum

PURPOSE

Laterally spreading tumors (LST) have been recognized worldwide. The aim of our retrospective study was to evaluate the clinicopathological differences of LST arising in the colon and rectum.

METHODS

We investigated the clinical records of consecutive patients with LST that were endoscopically or surgically resected at our hospital between February 2006 and March 2011. LST were classified into three types: granular-homogenous (LST-GH), granular-nodular mixed (LST-GM), and nongranular (LST-NG) types. We also defined the hardly elevated flat lesion with a dilated pit pattern that occurs at the margins of LST as the "skirt." The clinicopathological characteristics of the LST arising in the colon and rectum, including the presence of the skirt, were compared.

RESULTS

A total of 496 colorectal LST in 435 patients were examined. LST-GM was predominant in the rectum, whereas LST-NG was predominant in the colon (p < 0.001). The mean tumor size was larger in the rectum (39.3 ± 17.9 mm) than the colon (25.8 ± 13.6 mm) (p < 0.001). Low-grade dysplasia frequency was lower in the rectum than the colon (4 vs. 37%, p < 0.001). The skirt was identified in 15 lesions (3.0%), with a higher incidence in the rectum than the colon (17 vs. 0.5%, p < 0.001). The skirt was found only in LST-GM.

CONCLUSIONS

A greater proportion of LST-GM, greater mean size, and lower incidence of low-grade dysplasia were found in rectal LST. The skirt was a novel and unique finding, primarily observed in rectal LST-GM cases.

Whites and blacks have similar risk of metachronous advanced colorectal neoplasia

BACKGROUND

Current guidelines for surveillance of colonic neoplasia are based on data from predominantly white populations, yet whether these recommendations are applicable to blacks is unknown.

AIM

To define the prevalence of advanced colorectal neoplasia (ACN) among whites and blacks undergoing surveillance colonoscopy.

METHODS

This was a retrospective, cross-sectional analysis of asymptomatic, average-risk non-Hispanic white (N = 246) and non-Hispanic black (N = 203) patients with colorectal neoplasia who underwent baseline screening colonoscopy between January 1, 2000, and December 31, 2007, and a surveillance colonoscopy before December 31, 2010, at an academic safety-net hospital. The main outcome measure was the prevalence of ACN, defined as a tubular adenoma or sessile serrated adenoma (SSA) ≥ 10 mm, any adenoma with villous histology or high-grade dysplasia, any serrated lesion with dysplasia, or invasive cancer at surveillance.

RESULTS

During a median follow-up of 4.3 years, the overall prevalence of ACN at surveillance was similar among blacks and whites (11.3 vs. 9.8 %; P = 0.59) with an odds ratio of 1.18 (95 % CI 0.65-2.16) [corrected]. Blacks and whites with non-advanced neoplasia had similar rates of ACN at the 1-3, 4-5, and >5 year follow-up intervals. Blacks with ACN or multiplicity at baseline had higher rates of ACN at the 1- to 3-year interval compared with whites, but the difference was non-significant (26.7 vs. 12.5 %; P = 0.32). No interval cancers were observed for either group.

CONCLUSIONS

The overall prevalence of ACN was similar between non-Hispanic blacks and non-Hispanic whites undergoing surveillance in a safety-net healthcare setting suggesting that current surveillance guidelines are appropriate for both blacks and whites.

Experience of the endoscopist increases detection rates of smaller size and higher histological grade polyps

BACKGROUND

Adenoma and polyp detection rates (ADR and PDR, respectively) are important indicators of endoscopy quality, particularly in colorectal carcinoma screening.

OBJECTIVE

To assess the influence of the endoscopist's experience on the ADR and PDR.

PATIENTS AND METHODS

In this study, 9635 colonoscopies were screened during a 5-year period. Only 5738 were finally analyzed due to exclusion criteria. The endoscopists were separated in three groups of experience according to the number of colonoscopies performed in the past (yearly and total). The number of polyps and adenomas, as well as the size and histology of these polyps were recorded.

RESULTS

The ADR and PDR were similar regardless of the experience of the endoscopist, but those with more experience clearly found more polyps of less than 10 mm (P = 0.01) and of less than 3 mm (P < 0.0001). Most of the differences were due to a higher number of flat polyps detected by the experienced group. This study also shows that more experienced endoscopists detect adenomas with more advanced histology (P < 0.0001).

CONCLUSION

Even though the ADR and PDR are similar in all groups of endoscopists, the less experienced endoscopists could be missing some of the smaller polyps, sometimes with more advanced histology.

The Modified Mayo Clinic technique: Emphasis on plausible significant reduction of colon cancer

OBJECTIVE

To compare the ability to detect colonic polyps using a modified Mayo Clinic (MMC) barium enema technique with that of the usual gold standard optical colonoscopy (OC).

METHODS

Patients considered at an average or increased risk of colorectal cancer were initially screened using the MMC technique. Patients who refused OC, those who had isolated rectal lesions and those with incomplete OC were excluded. Patients with mass lesions in the right colon or left colon were further assessed using OC.

RESULTS

A total of 142 consecutive patients were examined using the MMC technique. Of these, 18 patients were found to have mass lesions in the right or left colon and were further evaluated using OC. Sensitivity and specificity of the MMC technique for detecting colonic polyps/cancers of ≥ 0.3 cm were 87.5% and 80.0%, respectively. Most significantly, for detecting polyps of ≥ 1.0 cm, the false-negative rate was 0%.

CONCLUSIONS

The MMC technique may provide an alternative screening method to OC for the detection of colorectal polyps, particularly in countries where resources are scarce.

A survey of colonoscopic surveillance after polypectomy

Purpose

Several guidelines have been proposed for surveillance colonoscopy after polypectomy. However, some discrepancies still exist between the guidelines and clinical practice. This study was conducted to identify Korean doctors' recommendations for the colonoscopic surveillance interval after polypectomy.

Methods

A survey of the attendees at the symposium of the 64th Annual Congress of the Korean Surgical Society was conducted. When the prepared clinical scenarios were given, attendees answered using a wireless radio-frequency audience response system. All responders' results were automatically counted immediately. Frequencies of different answers to each question were calculated, and our results were compared with those of previous surveys performed using the same questionnaire in the United States or Japan.

Results

The number of responder varied from 38 to 41. About 50% of valid responders selected 'follow-up in 3 years' for low-risk lesions, such as a 6-mm hyperplastic polyp, a 6-mm tubular adenoma, or two 6-mm tubular adenomas. Responders most-commonly selected 'follow-up in 1 year' for high-risk lesions, such as a 12-mm tubular adenoma with high grade dysplasia or a 12-mm tubulovillous adenoma. The majority of Korean doctors recommend postpolypectomy colonoscopic surveillance more frequently than American physicians did.

Conclusion

A discrepancy between the guidelines and clinical practice for the surveillance after polypectomy still exists in Korea. A surveillance program that can be easily and widely applied in clinical practice needs to be established.

Colorectal polyps and polyposis syndromes

A polyp is defined as any mass protruding into the lumen of a hollow viscus. Colorectal polyps may be classified by their macroscopic appearance as sessile (flat, arising directly from the mucosal layer) or pedunculated (extending from the mucosa through a fibrovascular stalk). Colorectal polyps may also be histologically classified as neoplastic or as non-neoplastic (hyperplastic, hamartomatous, or inflammatory). The neoplastic polyps are of primary importance because they harbor a malignant potential, which represents a stage in the development of colorectal cancer. For this reason, it is essential to identify these polyps at a sufficiently early stage, when a simple outpatient procedure to remove them can interrupt the development of colorectal cancer and prevent disease and death. When invasive carcinoma arises in a polyp, careful consideration must be given to ensuring the adequacy of treatment. Although most neoplastic polyps do not evolve into cancer, it is well accepted that the majority of colorectal carcinomas evolve from adenomatous polyps; the sequence of events leading to this transformation is referred to as the adenoma-to-carcinoma sequence. The presence of a systemic process that promotes the development of multiple gastro-intestinal polyps is termed 'polyposis'. Hereditary gastro-intestinal polyposis syndromes account for approximately 1% of all cases of colorectal cancer and are associated with a broad spectrum of extra-colonic tumors. Early detection and accurate classification of these syndromes are essential, in order to initiate a surveillance program for the early detection of cancer. Several polyposis syndromes have been described, each having its own genetic basis and characteristic polyp distribution, clinical presentation, and malignancy risk. Diagnostic modalities and treatment options for neoplastic polyps-as well as the most prevalent polyposis syndromes-are reviewed below.

High-definition endoscopy with i-Scan for evaluation of small colon polyps: the HiSCOPE study

BACKGROUND

Traditional white-light endoscopy cannot reliably distinguish between small (<10 mm) adenomatous and hyperplastic colon polyps. High-definition white-light (HDWL) endoscopy and i-Scan may improve in vivo characterization of small colon polyps.

OBJECTIVE

To compare HDWL endoscopy and HDWL plus i-Scan for the assessment of small colon polyps and to measure performance against the American Society for Gastrointestinal Endoscopy (ASGE) thresholds for assessment of diminutive colon polyps.

DESIGN

Prospective cohort study.

SETTING

Single academic hospital.

PATIENTS

Patients undergoing bowel cancer screening colonoscopy.

INTERVENTION

In vivo assessment of all polyps <10 mm by using HDWL and i-Scan image enhancement.

MAIN OUTCOME MEASUREMENTS

The primary outcome measure was overall diagnostic accuracy of in vivo assessment of colon polyps <10 mm. Secondary outcome measures were sensitivity and specificity for adenomatous histology, negative predictive value for adenomatous histology of diminutive rectosigmoid polyps, and accuracy of prediction of polyp surveillance intervals.

RESULTS

A total of 209 polyps in 84 patients were included. There were no significant differences between HDWL endoscopy and i-Scan in characterization of polyps <10 mm (accuracy 93.3% vs 94.7%; P = 1.00; sensitivity 95.5% vs 97.0%; P = .50; specificity 89.3% vs 90.7%; P = 1.00). The negative predictive value for adenomatous histology of diminutive rectosigmoid polyps was 100% with both HDWL endoscopy and i-Scan. U.K. and U.S. polyp surveillance intervals were predicted with 95.2% accuracy with HDWL endoscopy and 97.2% accuracy with i-Scan.

LIMITATIONS

Single-center study.

CONCLUSION

HDWL endoscopy may be as accurate as HDWL with i-Scan image enhancement for the in vivo characterization of small colon polyps. Both modalities fulfil the ASGE performance thresholds for the assessment of diminutive colon polyps. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01761279.).

General Properties of Colon Polyps in Central Anatolia

Aim

Polyp is called formations protruding into the lumen in the gastrointestinal tract. In this study, we aimed to determine frequency, anatomic distribution within the large bowel and pathologic types of colon polyps based on the colonoscopy results.

Materials and methods

The colonoscopy reports between 2010 and 2011 were analyzed retrospectively. Complaint of the patients on admission, the presence of polyps, anatomic distribution of polyps, polyp type and polyp size were evaluated.

Result

A total of 4000 colonoscopy reports were examined. The largest proportion of polyps occurred in the left colon (74.4%), followed by the ascending colon (11.5%). Eighty-five were adenomatous polyps, 71 were hyperplastic polyps, 12 were inflammatory polyps, 12 were serrated adenoma, 3 were adenocarcinoma, and 8 were tubulovillous adenomas.

Discussion

In light of like this study, the development of screening and follow-up programs in Turkey will be useful to reduce the incidence and mortality of colorectal cancer.

How to cite this article: Kefeli A, Basyigit S, Yeniova AO, Nazligul Y, Kucukazman M, Aktas B. General Properties of Colon Polyps in Central Anatolia. Euroasian J Hepato-Gastroenterol 2014;4(1):7-10.

Health benefits and cost-effectiveness of a hybrid screening strategy for colorectal cancer

BACKGROUND & AIMS

Colorectal cancer (CRC) screening guidelines recommend screening schedules for each single type of test except for concurrent sigmoidoscopy and fecal occult blood test (FOBT). We investigated the cost-effectiveness of a hybrid screening strategy that was based on a fecal immunological test (FIT) and colonoscopy.

METHODS

We conducted a cost-effectiveness analysis by using the Archimedes Model to evaluate the effects of different CRC screening strategies on health outcomes and costs related to CRC in a population that represents members of Kaiser Permanente Northern California. The Archimedes Model is a large-scale simulation of human physiology, diseases, interventions, and health care systems. The CRC submodel in the Archimedes Model was derived from public databases, published epidemiologic studies, and clinical trials.

RESULTS

A hybrid screening strategy led to substantial reductions in CRC incidence and mortality, gains in quality-adjusted life years (QALYs), and reductions in costs, comparable with those of the best single-test strategies. Screening by annual FIT of patients 50-65 years old and then a single colonoscopy when they were 66 years old (FIT/COLOx1) reduced CRC incidence by 72% and gained 110 QALYs for every 1000 people during a period of 30 years, compared with no screening. Compared with annual FIT, FIT/COLOx1 gained 1400 QALYs/100,000 persons at an incremental cost of $9700/QALY gained and required 55% fewer FITs. Compared with FIT/COLOx1, colonoscopy at 10-year intervals gained 500 QALYs/100,000 at an incremental cost of $35,100/QALY gained but required 37% more colonoscopies. Over the ranges of parameters examined, the cost-effectiveness of hybrid screening strategies was slightly more sensitive to the adherence rate with colonoscopy than the adherence rate with yearly FIT. Uncertainties associated with estimates of FIT performance within a program setting and sensitivities for flat and right-sided lesions are expected to have significant impacts on the cost-effectiveness results.

CONCLUSIONS

In our simulation model, a strategy of annual or biennial FIT, beginning when patients are 50 years old, with a single colonoscopy when they are 66 years old, delivers clinical and economic outcomes similar to those of CRC screening by single-modality strategies, with a favorable impact on resources demand.

A comparative overview of general risk factors associated with the incidence of colorectal cancer

Cancers found in colorectal region remain largely localized to the large intestine and rectum. They are derived from the epithelium and are considered to be among the most frequently detected cancers. They are known to occur in approximately 5 % population of the Western world. After metastasis, a patient's 5-year postsurgical survival chances unfortunately fall from 90 to 10 % or even less. Adenocarcinoma, the most common cell type of colon cancer, alone constitutes 95 % of the cases. Lymphoma and squamous cell carcinoma can also be found in some cases. Because 5 % of persons are predisposed to development of colorectal cancer, this disease has often been addressed as an important public health issue. Factors that are known in particular to increase a person's risk to develop this cancer are as follows: an individual's age, dietary habits, any complaint of obesity, diabetes, previous history of cancer or intestinal polyps, personal habit of alcohol consumption and smoking, family history of colon cancer, race, sex, and ethnicity. Since the risk of colorectal cancer is increasing steadily in Kashmir, India, like in some other corners of Asia, exhaustive efforts are being made to find the association of above given and other risk factors with the development of this gastrointestinal tract cancer. Adoption of Western life style, diet mimicry, together with a habit of having physically inactive life style and consumption of red meat in particular can be blamed as being active players to a considerable extent.

Expression of neutrophil gelatinase-associated lipocalin in colorectal neoplastic progression: a marker of malignant potential?

Background:

Neutrophil gelatinase-associated lipocalin (NGAL) has a diverse functional repertoire, involved in the innate immune response as well as cell growth and differentiation. Expression has been linked to malignant disease development and progression.

Methods:

Neutrophil gelatinase-associated lipocalin expression was assessed immunohistochemically in 98 colorectal neoplastic lesions (52 cancer polyps (CaPs) and 46 sporadic adenoma/adjacent normal mucosa paired specimens) to investigate association with adenoma progression and early colorectal carcinogenesis.

Results:

Within CaPs, all adenomatous and carcinomatous epithelium expressed NGAL, with 92% (43 out of 47) and 58% (19 out of 33) epithelial positivity, respectively, as well as positive stromal cell expression. This was significantly increased compared with normal mucosal epithelium (P=0.0001). Neutrophil gelatinase-associated lipocalin positivity was also identified in sporadic low-grade adenomas, in both the epithelial and stromal compartments as compared with adjacent normal mucosa (P=0.0001 and 0.0002), and this increased along with adenoma size >1 cm (P=0.03).

Conclusion:

Neutrophil gelatinase-associated lipocalin is expressed by the majority of human neoplastic colorectal lesions. This phenotypic switch occurs at an early stage in neoplastic progression with clear differential expression between normal mucosa and adenomatous polyps, rather than further downstream in disease progression at the adenoma–carcinoma transformation. Thus, NGAL expression is not a useful biomarker for determining disease progression from adenomatous to malignant colorectal neoplasia.

A prospective study of the accuracy and concordance between in-situ and postfixation measurements of colorectal polyp size and their potential impact upon surveillance

OBJECTIVES

To determine the differences between in-situ, prefixation and postfixation colorectal polyp measurements, their clinical impact upon determining adenoma surveillance intervals, and to compare postfixation measurements using three different devices.

PATIENTS AND METHODS

A prospective study of 107 colorectal polyps resected from 65 consecutive patients (45 men, 20 women) undergoing colonoscopy as part of the Bowel Cancer Screening Programme was undertaken. The polyps were measured in situ, prefixation (study gold standard) and using three measurement devices (ruler, callipers and magnifying lens) postfixation in formalin.

RESULTS

Prefixation ruler measurements were significantly higher than in-situ (P=0.02) and postfixation ruler measurements (P=0.04). No significant difference was observed between in-situ and postfixation ruler measurements (P=0.36), although in-situ measurements were more variable. In-situ measurements also generated more variation in surveillance intervals than postfixation measurements (9.3 vs. 5.6%). No significant difference was seen between measurements obtained by the three different devices postfixation (P=0.89).

CONCLUSION

This study provides evidence supporting the use of postfixation polyp size measurements as advised by recent European pathology colorectal cancer screening recommendations. In the absence of a clinically significant difference between measurement devices, we advise the ruler to be used as a standard for postfixation measurements because of its widespread availability.

Adenoma detection rate is necessary but insufficient for distinguishing high versus low endoscopist performance

BACKGROUND

Endoscopist quality is benchmarked by the adenoma detection rate (ADR)-the proportion of cases with 1 or more adenomas removed. However, the ADR rewards the same credit for 1 versus more than 1 adenoma.

OBJECTIVE

We evaluated whether 2 endoscopist groups could have a similar ADR but detect significantly different total adenomas.

DESIGN

We retrospectively measured the ADR and multiple measures of total adenoma yield, including a metric called ADR-Plus, the mean number of incremental adenomas after the first. We plotted ADR versus ADR-Plus to create 4 adenoma detection patterns: (1) optimal (↑ADR/↑ADR-Plus); (2) one and done (↑ADR/↓ADR-Plus); (3) all or none (↓ADR/↑ADR-Plus); (4) none and done (↓ADR/↓ADR-Plus).

SETTING

Tertiary-care teaching hospital and 3 nonteaching facilities servicing the same patient pool.

PATIENTS

A total of 3318 VA patients who underwent screening between 2005 and 2009.

MAIN OUTCOME MEASUREMENTS

ADR, mean total adenomas detected, advanced adenomas detected, ADR-Plus.

RESULTS

The ADR was 28.8% and 25.7% in the teaching (n = 1218) and nonteaching groups (n = 2100), respectively (P = .052). Although ADRs were relatively similar, the teaching site achieved 23.5%, 28.7%, and 29.5% higher mean total adenomas, advanced adenomas, and ADR-Plus versus nonteaching sites (P < .001). By coupling ADR with ADR-Plus, we identified more teaching endoscopists as optimal (57.1% vs 8.3%; P = .02), and more nonteaching endoscopists in the none and done category (42% vs 0%; P = .047).

LIMITATIONS

External generalizability, nonrandomized study.

CONCLUSION

We found minimal ADR differences between the 2 endoscopist groups, but substantial differences in total adenomas; the ADR missed this difference. Coupling the ADR with other total adenoma metrics (eg, ADR-Plus) provides a more comprehensive assessment of adenoma clearance; implementing both would better distinguish high- from low-performing endoscopists.

Evolving role of computed tomographic colonography in colon cancer screening and diagnosis

Computed tomographic colonography (CTC) is a relatively new imaging modality for the examination of patients for colorectal polyps and cancer. It has been validated in its accuracy for the detection of colon cancer and larger polyps (more than likely premalignant). CTC, however, is not widely accepted as a primary screening modality in the United States at present by many third-party payers, including Medicare, and its exact role in screening is evolving. Moreover, there has been opposition to incorporating CTC as an accepted screening instrument, especially by gastroenterologists. Heretofore, optical colonoscopy has been the mainstay in this screening. We discuss these issues and the continuing controversies concerning CTC.

Risk of colorectal adenomas in women with prior breast cancer

BACKGROUND AND AIMS

Longer life expectancy in patients with prior breast cancer may increase their risk of developing other primary cancers, including colorectal cancer (CRC). Whether the risk of developing CRC in this patient population is higher in comparison to those with no prior cancer remains unclear. The purpose of this study was to compare the prevalence of colorectal adenomas and any CRC in breast cancer survivors with those who have no history of prior cancer and assess any difference with use of antiestrogen therapy.

METHODS

We compared the prevalence of colorectal cancer and adenomas in breast cancer survivors with that of a group of matched controls. Eligible survivors were ≤85 years of age; had initially been diagnosed with stage 0, I, II, or III breast cancer; had completed all cancer treatments with the exception of adjuvant antiestrogen therapy; and had no evidence of recurrence on follow-up. We used the screening colonoscopy database at our institution to identify age-, sex-, and race-matched controls with no history of cancer.

RESULTS

We identified 302 study-eligible breast cancer survivors and 302 matched controls. No colorectal cancers were found in either group. Forty-one breast cancer survivors and 30 controls had tubular adenomas; four survivors and three controls had villous adenoma; and eight survivors and ten controls had advanced adenoma. Multivariate regression analysis revealed that adjuvant antiestrogen therapy was not significantly associated with an increased risk of advanced adenoma.

CONCLUSIONS

The prevalence of colorectal adenomas in breast cancer survivors and controls was similar. Breast cancer survivors, including those receiving adjuvant antiestrogen therapies may follow the colorectal screening guidelines used for average-risk population.

Molecular patterns in the evolution of serrated lesion of the colorectum

Colorectal cancer (CRC) mostly develops from a variety of polyps following mainly three different molecular pathways: chromosomal instability (CIN), microsatellite instability (MSI) and CpG island methylation (CIMP). Polyps are classified histologically as conventional adenomas, hyperplastic polyps, sessile serrated adenomas/polyps (SSA/P) and traditional serrated adenomas (TSA). However, the association of these polyps with the different types of CRCs and the underlying genetic and epigenetic aberrations has yet to be resolved. In order to address this question we analyzed 140 tumors and 20 matched mucosae by array comparative genomic hybridization, by sequence analysis of the oncogenes BRAF, KRAS, PI3K3CA and by methylation arrays. MSI was tested indirectly by immunohistochemistry (IHC) and a loss of MLH1, MSH2, MSH6 or PMS2 was assigned as high microsatellite instability (MSI-H), while low microsatellite instability (MSI-L) was defined as MGMT IHC negativity only. CIN was detected in 78% of all MSI-H CRCs, most commonly as a gain of chromosome 8. Methylation data analyses allowed classification of samples into four groups and detected similar methylation profiles in SSA/P and MSI-H CRC. TSA also revealed aberrant methylation pattern, but clustered more heterogeneously and closer to microsatellite stable (MSS) CRCs. SSA/P, TSA and MSI-H CRCs had the highest degree of promotor methylation (CIMP pathway). Chromosomal instability, in contrast to the established doctrine, is a common phenomenon in MSI CRCs, yet to a lower extent and at later stages than in MSS CRCs. Methylation analyses suggest that SSA/P are precursors for MSI-H CRCs and follow the CIMP pathway.

CT colonography of a Medicare-aged population: outcomes observed in an analysis of more than 1400 patients

OBJECTIVE

We evaluated outcomes of patients 65 years old and older who underwent CT colonography (CTC) between 2004 and 2009.

CONCLUSION

The frequency of referral to colonoscopy based on a polyp size threshold of 6 mm was 14.5%. Colorectal neoplasia was found in 9.3% of patients, with advanced neoplasia in 3.3%. Potentially important extracolonic findings were observed in 2.9% of patients. The low rates of referral to colonoscopy, prevalence of advanced neoplasia, and prevalence of extracolonic findings make CTC a viable option for Medicare-aged patients.

A randomized controlled trial of sodium phosphate tablets and polyethylene glycol solution for polyp detection

OBJECTIVE

The study was aimed to assess the efficacy of sodium phosphate (NaP) tablets and polyethylene glycol (PEG) on colon cleansing.

METHODS

A prospective, randomized trial was conducted at the Graduate School of Medicine, University of Tokyo. Participants who were scheduled for colonoscopy were included and randomized into either the NaP or PEG group. An interim analysis was programmed into the study design when approximately 50% of the enrolments were completed. The primary outcome was the detection rate of polyps with a diameter ≤5 mm.

RESULTS

A total of 92 patients were included in the analysis, of whom 44 were in the NaP group and 48 in the PEG group. The quality of colonic preparation was similar in both groups. The NaP group showed a higher detection rate of polyps with a diameter ≤5 mm than the PEG group (38.6% vs 18.8%, P = 0.004). A multivariate analysis showed that NaP and the withdrawal time of the colonoscope were independent factors associated with the detection of polyps with a diameter ≤5 mm.

CONCLUSIONS

NaP is certainly not inferior to PEG. In fact, the results suggest that diminutive polyp detection using NaP might be superior to that using PEG.