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

Feasibility of computed tomography colonography as a diagnostic procedure in colon cancer screening in India

Computed Tomography Colonography (CTC) is a medical imaging technology used in identifying polyps and colon cancer masses in the large intestine. The technique has evolved a great deal since its invention and has become a routine diagnostic procedure in Western countries due to its non invasiveness and ease of use. The objective of our study was to explore the possibility of CTC application in Indian hospitals. This paper gives an overview of the procedure and its commercial viability. The explanation begins with the domain aspects from gastroenterologist perspective, the new way of thinking in polyp classification, the technical components of CTC procedure, and how engineering solutions have helped clinicians in solving the complexities involved in colon diagnosis. The colon cancer statistics in India and the results of single institution study we carried out with retrospective data is explained. By considering the increasing number of patients developing colon malignancies, the practicality of CTC in Indian hospitals is discussed. This paper does not reveal any technical aspects (algorithms) of engineering solutions implemented in CTC.

Colonoscopy utilization and outcomes 2000 to 2011

BACKGROUND

Understanding colonoscopy utilization and outcomes can help determine when the procedure is most effective.

OBJECTIVE

To study trends in utilization and outcomes of colonoscopy in the United States from 2000 to 2011.

DESIGN

Prospective collection of colonoscopy data.

SETTING

A total of 84 adult diverse GI practices.

PATIENTS

All adult patients receiving colonoscopy for any reason.

INTERVENTION

Colonoscopy.

MAIN OUTCOME MEASUREMENTS

Polyps >9 mm or suspected malignant tumor.

RESULTS

We analyzed 1,372,838 reports. The most common reason for colonoscopy in patients aged <50 years is evaluation of symptoms such as irritable bowel syndrome (IBS) (28.7%) and bleeding or anemia (35.3%). In patients aged 50 to 74 years, colorectal cancer screening accounts for 42.9% of examinations. In patients aged >74 years, surveillance for cancer or polyps is the most common indication. The use of colonoscopy for average-risk screening increased nearly 3-fold during the study period. The prevalence of large polyps increases with age and is higher in men for every procedure indication. The prevalence of large polyps in patients with symptoms of IBS was lower than in those undergoing average-risk screening (odds ratio [OR] 0.85; 95% confidence interval [CI], 0.83-0.87). With increasing age, there was a shift from distal to proximal large polyps. The rate of proximal large polyps is higher in the black population compared with the white population (OR 1.19; 95% CI, 1.13-1.25).

LIMITATIONS

In the absence of pathology data, use of surrogate as the main outcome.

CONCLUSION

Colonoscopy utilization changed from 2000 to 2011, with an increase in primary screening. The proximal location of large polyps in the black population and with advancing age has implications for screening and surveillance.

What clinicians wish to know about benign colorectal polyps: an operative classification

INTRODUCTION

In recent years we assisted to a real "boom" of colorectal polyps, mainly due to the diffusion of screening procedures and of colonoscopy. This new "Polyp Epidemic" raises a series of problems and challenges. It became clear that many syndromes are defined by the number, histological type and location of polyps, together with extraintestinal manifestations and, in most cases, specific molecular changes. This paper discusses some of the above mentioned points, focusing on the relative role of endoscopists and pathologists. The objective is to reach an operative classification of the most common polyps observed in daily practice which might be of help for the identification of inherited syndromes.

METHODS AND RESULTS

Six main histological types of polyps are defined and underlined: Adenoma, hyperplastic/serrated, hamartoma, ganglioneuroma, mixed, inflammatory. The importance of a brief description, in pathology reports, of each type of polyps is fundamental for a correct diagnosis. Each of the defined polyps is associated with inherited syndromes whose genetic basis has recently been elucidated. Relevant information should be given, and separated from additional (and not strictly necessary) information.

RECOMMENDATIONS

A correct polyp analysis is a valuable element for identifying specific inherited syndromes. Polyps represent a precious tool for planning screening and follow-up in a given individual. In addition, these lesions focus the interest of clinicians toward syndrome which were considered as rare diseases; indeed, the explosion of molecular biology and the diffusion of colonoscopy revealed that these conditions are frequent and amenable of treatment.

ACR Appropriateness Criteria colorectal cancer screening

Colorectal cancer is the third leading cause of cancer deaths in the United States. Most colorectal cancers can be prevented by detecting and removing the precursor adenomatous polyp. Individual risk factors for the development of colorectal cancer will influence the particular choice of screening tool. CT colonography (CTC) is the primary imaging test for colorectal cancer screening in average-risk individuals, whereas the double-contrast barium enema (DCBE) is now considered to be a test that may be appropriate, particularly in settings where CTC is unavailable. Single-contrast barium enema has a lower performance profile and is indicated for screening only when CTC and DCBE are not available. CTC is also the preferred test for colon evaluation following an incomplete colonoscopy. Imaging tests including CTC and DCBE are not indicated for colorectal cancer screening in high-risk patients with polyposis syndromes or inflammatory bowel disease. This paper presents the updated colorectal cancer imaging test ratings and is the result of evidence-based consensus by the ACR Appropriateness Criteria Expert Panel on Gastrointestinal Imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Multitarget stool DNA testing for colorectal-cancer screening

BACKGROUND

An accurate, noninvasive test could improve the effectiveness of colorectal-cancer screening.

METHODS

We compared a noninvasive, multitarget stool DNA test with a fecal immunochemical test (FIT) in persons at average risk for colorectal cancer. The DNA test includes quantitative molecular assays for KRAS mutations, aberrant NDRG4 and BMP3 methylation, and β-actin, plus a hemoglobin immunoassay. Results were generated with the use of a logistic-regression algorithm, with values of 183 or more considered to be positive. FIT values of more than 100 ng of hemoglobin per milliliter of buffer were considered to be positive. Tests were processed independently of colonoscopic findings.

RESULTS

Of the 9989 participants who could be evaluated, 65 (0.7%) had colorectal cancer and 757 (7.6%) had advanced precancerous lesions (advanced adenomas or sessile serrated polyps measuring ≥1 cm in the greatest dimension) on colonoscopy. The sensitivity for detecting colorectal cancer was 92.3% with DNA testing and 73.8% with FIT (P=0.002). The sensitivity for detecting advanced precancerous lesions was 42.4% with DNA testing and 23.8% with FIT (P<0.001). The rate of detection of polyps with high-grade dysplasia was 69.2% with DNA testing and 46.2% with FIT (P=0.004); the rates of detection of serrated sessile polyps measuring 1 cm or more were 42.4% and 5.1%, respectively (P<0.001). Specificities with DNA testing and FIT were 86.6% and 94.9%, respectively, among participants with nonadvanced or negative findings (P<0.001) and 89.8% and 96.4%, respectively, among those with negative results on colonoscopy (P<0.001). The numbers of persons who would need to be screened to detect one cancer were 154 with colonoscopy, 166 with DNA testing, and 208 with FIT.

CONCLUSIONS

In asymptomatic persons at average risk for colorectal cancer, multitarget stool DNA testing detected significantly more cancers than did FIT but had more false positive results. (Funded by Exact Sciences; ClinicalTrials.gov number, NCT01397747.).

Current management of diminutive colorectal polyps in Taiwan

The majority of polyps detected during colonoscopy are diminutive polyps, for which the cost of pathological analysis is substantial. In our analysis of a screening cohort of 10737 subjects undergoing screening colonoscopy, a total of 15877 neoplastic lesions were detected, of which 10816 (68.1%) were diminutive lesions. Of those diminutive lesions, 90 (0.83%) had a villous component, 14 (0.1%) had high-grade dysplasia, and none had invasive cancer. Only 1.3% of patients were advised to decrease their surveillance interval because of unfavorable histology. Laws regulating medical practice, uncertainty regarding the accuracy of endoscopic diagnosis of diminutive polyps outside of academic centers, and the relatively low cost of pathological analysis are among the barriers to adopting a 'resect and discard' practice in Taiwan.

A direct comparison of the prevalence of advanced adenoma and cancer between surveillance and screening colonoscopies

BACKGROUND/AIMS

Surveillance colonoscopy is recommended after polypectomy of adenoma and surgery for colorectal cancer. The purpose of this study was to assess the frequency of advanced adenoma and cancer in colonoscopies performed for surveillance compared to screening colonoscopies.

METHODS

Analysis of relative frequencies of findings in colonoscopies performed for post-adenoma surveillance (post-ad), post-cancer surveillance (post-crc), screening, and follow-up of a positive fecal occult blood test (FOBT). Logistic regression was used to identify the risk for advanced adenoma (adenoma ≥10 mm, containing high-grade dysplasia, or villous histology) and cancer.

RESULTS

324,912 colonoscopies were included in the analysis: 81,877 post-ad, 26,896 post-crc, 178,305 screening, 37,834 positive FOBT. Advanced adenoma (cancer) was diagnosed in 8.0% (0.4%) of post-ad, 5.0% (1.0%) of post-crc, 7.4% (1.1%) of screening, and 11.7% (3.6%) of positive FOBT colonoscopies. Compared to screening, the odds ratios for finding advanced adenoma were 0.93 (95% CI 0.88-0.98) for post-ad, 0.96 (0.86-1.08) for post-crc, and 1.18 (1.09-1.28) for positive FOBT colonoscopies. The odds ratios for the diagnosis of cancer were 0.29 (0.24-0.36) for post-ad, 0.81 (0.61-1.07) for post-crc, and 2.77 (2.43-3.17) for positive FOBT.

CONCLUSION

Colonoscopy for post-ad surveillance but not colonoscopy for post-crc surveillance is associated with a lower risk of diagnosis of advanced adenoma and cancer.

Limited life expectancy among a subgroup of medicare beneficiaries receiving screening colonoscopies

BACKGROUND & AIMS

Life expectancy is an important consideration when assessing appropriateness of preventive programs for older individuals. Most studies on this subject have used age cutoffs as a proxy for life expectancy. We analyzed patterns of utilization of screening colonoscopy in Medicare enrollees by using estimated life expectancy.

METHODS

We used a 5% random national sample of Medicare claims data to identify average-risk patients who underwent screening colonoscopies from 2008 to 2010. Colonoscopies were considered to be screening colonoscopies in the absence of diagnoses for nonscreening indications, which were based on either colonoscopies or any claims in the preceding 3 months. We estimated life expectancies by using a model that combined age, sex, and comorbidity. Among patients who underwent screening colonoscopies, we calculated the percentage of those with life expectancies <10 years.

RESULTS

Among the 57,597 Medicare beneficiaries 66 years old or older who received at least 1 screening colonoscopy, 24.8% had an estimated life expectancy of <10 years. There was a significant positive association between total Medicare per capita costs in hospital referral regions and the proportion of patients with limited life expectancies (<10 years) at the time of screening colonoscopy (R = 0.25; P < .001, Pearson correlation test). In a multivariable analysis, men were substantially more likely than women to have limited life expectancy at the time of screening colonoscopy (odds ratio, 2.25; 95% confidence interval, 2.16-2.34).

CONCLUSIONS

Nearly 25% of Medicare beneficiaries, especially men, had life expectancies <10 years at the time of screening colonoscopies. Life expectancy should therefore be incorporated in decision-making for preventive services.

Competition in Colon Cancer Screening? What Is the Role of Colonoscopy?

BACKGROUND

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the Western world. The incidence could be reduced if this cancer were to be diagnosed at an early stage of disease. A competition has started between the existing screening methods to be the most efficient in detecting premalignant conditions. This review illustrates the current state of screening techniques for CRC.

METHOD

Pubmed was searched for meta-analyses and prospective studies on screening for CRC, with an emphasis on colonography, computed tomographic colonography (CTC), magnetic resonance colonography (MRC), stool DNA testing, and colon capsule endoscopy, and critical appraisal of the research was done by the reviewers.

RESULTS

The imaging techniques (CTC and MRC) had similar detection rates for bigger lesions (≥10 mm) as colonoscopy. High-definition colonoscopy showed better efficiency with smaller lesions. The techniques developing around colonoscopy such as the retro-viewing colonoscope, the balloon colonoscope, or the 330-degree viewing colonoscope try to enhance efficacy by reducing the adenoma miss rate in right-sided, non-polypoid lesions. Colon capsule endoscopy and the stool detection systems are limited to identifying cancer but not necessarily adenomas.

CONCLUSION

Colonoscopy is the preferred CRC screening strategy and the undisputed gold standard in terms of efficacy.

Metabolic syndrome is associated with increased prevalence of advanced colorectal polyps

OBJECTIVES

To examine the association between metabolic syndrome (MetS) and/or its components and colorectal neoplasms in adult population undergoing screening colonoscopy.

DESIGN

Cross-sectional study.

SETTING

Institute of Gastroenterology, Kaplan Medical Center, Rehovot, Israel.

PARTICIPANTS

Two hundred ninety nine consecutive outpatients undergoing screening colonoscopy.

MEASUREMENTS

MetS was determined according to the Adult Treatment Panel III of the National Cholesterol Education Program (ATP III) criteria. Blood test results and other clinical data were retrieved from the electronic medical records.

RESULTS

In 94 patients (31.8%) polyps were detected. Thirty two (34%) of the polyps were advanced. Eighty one percent of patients with an advanced polyp met the criteria for MetS. About the same MetS prevalence (84%) was found in men, but not in women. An advanced polyp was detected in 14% of patients with MetS, compared to 5% of patients without MetS. Odds ratio for having an advanced polyp in a patient with MetS compared to a patient without MetS was 10.64.

CONCLUSION

MetS was found to be a risk factor for advanced polyps. This association is suggestive of the need that patients with MetS should be urged to have a screening colonoscopy.

In vivo diagnostic accuracy of high-resolution microendoscopy in differentiating neoplastic from non-neoplastic colorectal polyps: a prospective study

OBJECTIVES

High-resolution microendoscopy (HRME) is a low-cost, "optical biopsy" technology that allows for subcellular imaging. The purpose of this study was to determine the in vivo diagnostic accuracy of the HRME for the differentiation of neoplastic from non-neoplastic colorectal polyps and compare it to that of high-definition white-light endoscopy (WLE) with histopathology as the gold standard.

METHODS

Three endoscopists prospectively detected a total of 171 polyps from 94 patients that were then imaged by HRME and classified in real-time as neoplastic (adenomatous, cancer) or non-neoplastic (normal, hyperplastic, inflammatory).

RESULTS

HRME had a significantly higher accuracy (94%), specificity (95%), and positive predictive value (PPV, 87%) for the determination of neoplastic colorectal polyps compared with WLE (65%, 39%, and 55%, respectively). When looking at small colorectal polyps (less than 10 mm), HRME continued to significantly outperform WLE in terms of accuracy (95% vs. 64%), specificity (98% vs. 40%) and PPV (92% vs. 55%). These trends continued when evaluating diminutive polyps (less than 5 mm) as HRME's accuracy (95%), specificity (98%), and PPV (93%) were all significantly greater than their WLE counterparts (62%, 41%, and 53%, respectively).

CONCLUSIONS

In conclusion, this in vivo study demonstrates that HRME can be a very effective modality in the differentiation of neoplastic and non-neoplastic colorectal polyps. A combination of standard white-light colonoscopy for polyp detection and HRME for polyp classification has the potential to truly allow the endoscopist to selectively determine which lesions can be left in situ, which lesions can simply be discarded, and which lesions need formal histopathologic analysis.

Quality in colonoscopy: European perspectives and practice

Colonoscopy is the 'gold standard' investigation of the colon. High quality colonoscopy is essential to diagnose early cancer and reduce its incidence through the detection and removal of pre-malignant adenomas. In this review, we discuss the key components of a high quality colonoscopy, review methods for improving quality, emerging technologies that have the potential to improve quality and highlight areas for future work.

Narrow band imaging to differentiate neoplastic and non-neoplastic colorectal polyps in real time: a meta-analysis of diagnostic operating characteristics

PURPOSE

Many studies have reported on the use of narrow band imaging (NBI) colonoscopy to differentiate neoplastic from non-neoplastic colorectal polyps. It has potential to replace pathological diagnosis of diminutive polyps. We aimed to perform a systematic review and meta-analysis on the real-time diagnostic operating characteristics of NBI colonoscopy.

METHODS

We searched PubMed, SCOPUS and Cochrane databases and abstracts. We used a two-level bivariate meta-analysis following a random effects model to summarise the data and fit hierarchical summary receiver-operating characteristic (HSROC) curves. The area under the HSROC curve serves as an indicator of the diagnostic test strength. We calculated summary sensitivity, specificity and negative predictive value (NPV). We assessed agreement of surveillance interval recommendations based on endoscopic diagnosis compared to pathology.

RESULTS

For NBI diagnosis of colorectal polyps, the area under the HSROC curve was 0.92 (95% CI 0.90 to 0.94), based on 28 studies involving 6280 polyps in 4053 patients. The overall sensitivity was 91.0% (95% CI 87.6% to 93.5%) and specificity was 82.6% (95% CI 79.0% to 85.7%). In eight studies (n=2146 polyps) that used high-confidence diagnostic predictions, sensitivity was 93.8% and specificity was 83.3%. The NPVs exceeded 90% when 60% or less of all polyps were neoplastic. Surveillance intervals based on endoscopic diagnosis agreed with those based on pathology in 92.6% of patients (95% CI 87.9% to 96.3%).

CONCLUSIONS

NBI diagnosis of colorectal polyps is highly accurate--the area under the HSROC curve exceeds 0.90. High-confidence predictions provide >90% sensitivity and NPV. It shows high potential for real-time endoscopic diagnosis.

Colonoscopic Polypectomies and Recommendations on the Colonoscopy Follow-up Intervals Depending on Endoscopic and Histopathological Findings

The Aim:

To show histopathological diagnoses after colonoscopic polypectomy in the University Hospital Center (KBC) Split with recommendations on further follow-up colonoscopy depending on the endoscopic and histological findings.

Patients and Methods:

The study included 2842 patients who underwent colonoscopy in a two-year period (2008-2009), followed by a detailed analysis of 350 patients in which one or more polyps were simultaneously removed and 163 patients who were only sampled for histological analysis. Patients from the National Program for Colorectal Cancer Prevention and patients in which colonoscopy is indicated as part of daily outpatient or inpatient treatment were included as well.

Results:

During 2008 and 2009 in KBC Split, out of a total of 2842 colonoscopies, 350 patients underwent colonoscopic polypectomy, whereby 618 polyps were removed (1-8 polyps in individual patients), while in 163 patients only biopsy specimens were sampled. Out of the total of 557 polyps sent for histological analysis, 236 were hyperplastic (42%), 193 were identified as tubular adenoma (35%), 84 were tubulovillous (15%), 18 villous (3%), 9 were adenocarcinoma (2%) and other 17 (3%). In 35 (15.4%) polyps high-grade dysplasia was found. The largest number of nonpolypectomized changes confirmed the presence of adenocarcinoma (76-47%), adenomas and hyperplastic polyps were 37 (22%) and regular findings 23 (14%). Mucosal high-grade dysplasia was demonstrated in 35 (23.1%) biopsied changes.

Conclusion:

Colonoscopies with polypectomy decreased the risk of the formation of colorectal cancer in these patients almost to the level of risk in patients who have not even had a polyp during colonoscopy. Arguably the best method of prevention and early detection of colorectal cancer are already widely established national programs. The next qualitative level is constantly improving the quality of colonoscopy with clear criteria and the establishment of a body to evaluate the performers and the equipment, and making recommendations on the colonoscopy follow-up intervals depending on endoscopic and histopathological findings of patients who for any reason underwent colonoscopy.

Application of colon capsule endoscopy (CCE) to evaluate the whole gastrointestinal tract: a comparative study of single-camera and dual-camera analysis

Background and study aims

Colon capsule endoscopy (CCE) was developed for the evaluation of colorectal pathology. In this study, our aim was to assess if a dual-camera analysis using CCE allows better evaluation of the whole gastrointestinal (GI) tract compared to a single-camera analysis.

Patients and methods

We included 21 patients (12 males, mean age 56.20 years) submitted for a CCE examination. After standard colon preparation, the colon capsule endoscope (PillCam Colon™) was swallowed after reinitiation from its “sleep” mode. Four physicians performed the analysis: two reviewed both video streams at the same time (dual-camera analysis); one analyzed images from one side of the device (“camera 1”); and the other reviewed the opposite side (“camera 2”). We compared numbers of findings from different parts of the entire GI tract and level of agreement among reviewers.

Results

A complete evaluation of the GI tract was possible in all patients. Dual-camera analysis provided 16% and 5% more findings compared to camera 1 and camera 2 analysis, respectively. Overall agreement was 62.7% (kappa = 0.44, 95% CI: 0.373–0.510). Esophageal (kappa = 0.611) and colorectal (kappa = 0.595) findings had a good level of agreement, while small bowel (kappa = 0.405) showed moderate agreement.

Conclusion

The use of dual-camera analysis with CCE for the evaluation of the GI tract is feasible and detects more abnormalities when compared with single-camera analysis.

Colonoscopic polypectomy: current techniques and controversies

Colonoscopic polypectomy is fundamental to effective colonoscopy. Through its impact on the polyp-cancer sequence, colonoscopic polypectomy reduces colorectal cancer incidence and mortality. Because it eliminates electrosurgical risk, cold snaring has emerged as the preferred technique for most small and all diminutive polyps. Few clinical trial data are available on the effectiveness and safety of specific techniques. Polypectomy technique seems highly variable between endoscopists, with some techniques more effective than others are. Further research is needed to investigate operator variation in polypectomy outcomes and establish an evidence base for best practice.

Female-specific rectal carcinogenesis in cyclin D1b transgenic mice

Human cyclin D1 generates two major isoforms via alternative splicing: cyclin D1a and cyclin D1b. Cyclin D1b is hardly expressed in normal tissues but is frequently expressed in certain types of cancer tissues. To clarify the oncogenic potential of cyclin D1b variant, we developed cyclin D1b transgenic (Tg) mice and analyzed their phenotypes. We detected rectal tumors in 63% (15/24) of the female Tg mice. All rectal tumors had the histological characteristics similar to human sessile serrated adenoma/polyps (SSA/Ps). Adenocarcinomas were also found in 53% (8/15) of the rectal tumors, suggesting that these adenocarcinomas originated from the SSA/P-like lesions. No rectal tumors were found in the ovariectomized female cyclin D1b Tg mice (0/10), indicating that ovarian hormones played a critical role in rectal carcinogenesis in these Tg mice. Both phosphorylation of Erk, without activating MEK, and expression of estrogen receptor β were elevated in the rectal tumors of female cyclin D1b Tg mice compared with normal rectums of female wild-type mice. In addition, we established a cell line, D1bTgRT, derived from a rectal cancer of female Tg mouse. Small interfering RNA-induced cyclin D1b knockdown in this cell line suppressed Erk phosphorylation, anchorage-independent growth, cell invasiveness and tumorigenicity in nude mice. In humans, expression of cyclin D1b messenger RNA was detected in 17% (1/6) of colorectal cancer cell lines and 9.7% (3/31) of colorectal cancer tissues. Taken together, these results indicate that cyclin D1b expression contributes to the female- specific rectal carcinogenesis in mouse model.

Missed lesions at CT colonography: lessons learned

Misinterpretation at CT colonography (CTC) can result in either a colorectal lesion being missed (false-negative) or a false-positive diagnosis. This review will largely focus on potential missed lesions-and ways to avoid such misses. The general causes of false-negative interpretation at CTC can be broadly characterized and grouped into discrete categories related to suboptimal study technique, specific lesion characteristics, anatomic location, and imaging artifacts. Overlapping causes further increase the likelihood of missing a clinically relevant lesion. In the end, if the technical factors of bowel preparation, colonic distention, and robust CTC software are adequately addressed on a consistent basis, and the reader is aware of all the potential pitfalls at CTC, important lesions will seldom be missed.

An international review of the main cost-effectiveness drivers of virtual colonography versus conventional colonoscopy for colorectal cancer screening: is the tide changing due to adherence?

OBJECTIVES

The majority of recent cost-effectiveness reviews concluded that computerised tomographic colonography (CTC) is not a cost-effective colorectal cancer (CRC) screening strategy yet. The objective of this review is to examine cost-effectiveness of CTC versus optical colonoscopy (COL) for CRC screening and identify the main drivers influencing cost-effectiveness due to the emergence of new research.

METHODS

A systematic review was conducted for cost-effectiveness studies comparing CTC and COL as a screening tool and providing outcomes in life-years saved, published between January 2006 and November 2012.

RESULTS

Nine studies were included in the review. There was considerable heterogeneity in modelling complexity and methodology. Different model assumptions and inputs had large effects on resulting cost-effectiveness of CTC and COL. CTC was found to be dominant or cost-effective in three studies, assuming the most favourable scenario. COL was found to be not cost effective in one study.

CONCLUSIONS

CTC has the potential to be a cost-effective CRC screening strategy when compared to COL. The most important assumptions that influenced the cost-effectiveness of CTC and COL were related to CTC threshold-based reporting of polyps, CTC cost, CTC sensitivity for large polyps, natural history of adenoma transition to cancer, AAA parameters and importantly, adherence. There is a strong need for a differential consideration of patient adherence and compliance to CTC and COL. Recent research shows that laxative-free CTC screening has the potential to become a good alternative screening method for CRC as it can improve patient uptake of screening.

Gastroenterology trainees can easily learn histologic characterization of diminutive colorectal polyps with narrow band imaging

BACKGROUND & AIMS

Little is known about how teaching gastroenterology trainees polyp patterns by using narrow band imaging (NBI) affects their ability to characterize the histology of diminutive colorectal polyps. We developed and tested a tool to teach trainees to characterize the histology of diminutive polyps by using NBI.

METHODS

Twelve gastroenterology trainees with varying levels of colonoscopy experience watched a teaching tool that described the NBI criteria to distinguish polyp histology. The trainees then watched 80 videos of NBI examination of diminutive polyps, recording their predictions of polyp histology and their degree of confidence. After each video, an expert provided feedback about actual polyp histology and the NBI criteria that supported each diagnosis. Twelve weeks later, without training or feedback during the interval, the trainees watched the same videos and predicted histologies of the polyps. Performance was evaluated by comparing predicted classification with actual histologic findings. Cumulative sum analysis was used to determine the learning curve for each trainee.

RESULTS

Trainees made significant improvements in accuracy and the proportion of high-confidence predictions as they progressed through video blocks during the first session (P < .001). With active feedback, all trainees predicted polyp histologies with >90% accuracy, with a negative predictive value >90% for adenomatous histology. A median of 49 videos was required to achieve competency. For diagnoses made with high confidence, trainee performance exceeded 90% during the first and second sessions. Interobserver agreement was substantial (session 1, κ = 0.71; session 2, κ = 0.70).

CONCLUSIONS

We developed a computer-based tool, combined with short videos and active feedback, to train gastroenterologists to identify polyp histology by using NBI. After training, gastroenterology trainees characterized the histology of diminutive polyps with ≥ 90% accuracy.

Optical diagnosis of colorectal polyps using high-definition i-scan: An educational experience

AIM: To examine performances regarding prediction of polyp histology using high-definition (HD) i-scan in a group of endoscopists with varying levels of experience.

METHODS: We used a digital library of HD i-scan still images, comprising twin pictures (surface enhancement and tone enhancement), collected at our university hospital. We defined endoscopic features of adenomatous and non-adenomatous polyps, according to the following parameters: color, surface pattern and vascular pattern. We familiarized the participating endoscopists on optical diagnosis of colorectal polyps using a 20-min didactic training session. All endoscopists were asked to evaluate an image set of 50 colorectal polyps with regard to polyp histology. We classified the diagnoses into high confidence (i.e., cases in which the endoscopist could assign a diagnosis with certainty) and low confidence diagnoses (i.e., cases in which the endoscopist preferred to send the polyp for formal histology). Mean sensitivity, specificity and accuracy per endoscopist/image were computed and differences between groups tested using independent-samples t tests. High vs low confidence diagnoses were compared using the paired-samples t test.

RESULTS: Eleven endoscopists without previous experience on optical diagnosis evaluated a total of 550 images (396 adenomatous, 154 non-adenomatous). Mean sensitivity, specificity and accuracy for diagnosing adenomas were 79.3%, 85.7% and 81.1%, respectively. No significant differences were found between gastroenterologists and trainees regarding performances of optical diagnosis (mean accuracy 78.0% vs 82.9%, P = 0.098). Diminutive lesions were predicted with a lower mean accuracy as compared to non-diminutive lesions (74.2% vs 93.1%, P = 0.008). A total of 446 (81.1%) diagnoses were made with high confidence. High confidence diagnoses corresponded to a significantly higher mean accuracy than low confidence diagnoses (84.0% vs 64.3%, P = 0.008). A total of 319 (58.0%) images were evaluated as having excellent quality. Considering excellent quality images in conjunction with high confidence diagnosis, overall accuracy increased to 92.8%.

CONCLUSION: After a single training session, endoscopists with varying levels of experience can already provide optical diagnosis with an accuracy of 84.0%.

Colonic polyps: are we ready to resect and discard?

Colorectal cancer represents a major cause of mortality in Western countries, and population-based colonoscopy screening is supported by official guidelines. A significant determinant of the cost of colonoscopy screening/surveillance is driven by polypectomy of diminutive (≤5 mm) lesions. When considering the low prevalence of advanced neoplasia within diminutive polyps, the additional cost of pathologic examination is mainly justified by the need to differentiate between precancerous adenomatous versus hyperplastic polyps. The aim of this review is to summarize the data supporting the clinical application of a resect and discard strategy, also addressing the potential pitfalls associated with this approach.

Assessment of volumetric growth rates of small colorectal polyps with CT colonography: a longitudinal study of natural history

BACKGROUND

The clinical relevance and in-vivo growth rates of small (6-9 mm) colorectal polyps are not well established. We aimed to assess the behaviour of such polyps with CT colonography assessments.

METHODS

In this longitudinal study, we enrolled asymptomatic adults undergoing routine colorectal cancer screening with CT colonography at two medical centres in the USA. Experienced investigators (PJP, DHK, JLH) measured volumes and maximum linear sizes of polyps in vivo with CT colonography scans at baseline and surveillance follow-up. We defined progression, stability, and regression on the basis of a 20% volumetric change per year from baseline (20% or more growth classed as progression, 20% growth to -20% reduction classed as stable, and -20% or more reduction classed as regression). We compared findings with histological subgroups confirmed after colonoscopy when indicated. This study is registered with ClinicalTrials.gov, number NCT00204867.

FINDINGS

Between April, 2004, and June, 2012, we screened 22,006 asymptomatic adults and included 243 adults (mean age 57·4 years [SD 7·1] and median age 56 years [IQR 52-61]; 106 [37%] women), with 306 small colorectal polyps. The mean surveillance interval was 2·3 years (SD 1·4; range 1-7 years; median 2·0 years [IQR 1·1-2·3]). 68 (22%) of 306 polyps progressed, 153 (50%) were stable, and 85 (28%) regressed, including an apparent resolution in 32 (10%) polyps. We established immediate histology in 131 lesions on colonoscopy after final CT colonography. 21 (91%) of 23 proven advanced adenomas progressed, compared with 31 (37%) of 84 proven non-advanced adenomas, and 15 (8%) of 198 other lesions (p<0·0001). The odds ratio for a growing polyp at CT colonography surveillance to become an advanced adenoma was 15·6 (95% CI 7·6-31·7) compared with 6-9 mm polyps detected and removed at initial CT colonography screening (without surveillance). Mean polyp volume change was a 77% increase per year for 23 proven advanced adenomas and a 16% increase per year for 84 proven non-advanced adenomas, but a 13% decrease per year for all proven non-neoplastic or unresected polyps (p<0·0001). An absolute polyp volume of more than 180 mm(3) at surveillance CT colonography identified proven advanced neoplasia (including one delayed cancer) with a sensitivity of 92% (22 of 24 polyps), specificity of 94% (266 of 282 polyps), positive-predictive value of 58% (22 of 38 polyps), and negative-predictive value of 99% (266 of 268 polyps). Only 16 (6%) of the 6-9 mm polyps exceeded 10 mm at follow-up.

INTERPRETATION

Volumetric growth assessment of small colorectal polyps could be a useful biomarker for determination of clinical importance. Advanced adenomas show more rapid growth than non-advanced adenomas, whereas most other small polyps remain stable or regress. Our findings might allow for less invasive surveillance strategies, reserving polypectomy for lesions that show substantial growth. Further research is needed to provide more information regarding the ultimate fate of unresected small polyps without significant growth.

FUNDING

US National Institutes of Health, National Cancer Institute.

Clinical practice variation in the management of diminutive colorectal polyps: results of a national survey of gastroenterologists

OBJECTIVES

We investigated physician beliefs and behaviors regarding diminutive colorectal polyps and the contribution of these beliefs to variable detection rates.

METHODS

One hundred sixty-seven members of the American College of Gastroenterology took a Web-based survey. We compared respondents and nonrespondents using demographic and practice information from the American Medical Association Physician Masterfile.

RESULTS

Respondents varied in their definition of diminutive polyps. Respondents acknowledged leaving diminutive polyps in place during colonoscopy in various scenarios. Years in practice, confidence in endoscopic histologic diagnosis, and never having seen advanced histology in a diminutive polyp were predictive of leaving polyps in place. The majority of respondents were at least somewhat agreeable to leaving diminutive polyps in place if guidelines endorsed this practice.

CONCLUSIONS

Gastroenterologists vary in their removal of diminutive polyps. The results have implications for the interpretation and management of variable polyp detection rates.

Magnetic resonance colonography for the detection of colorectal neoplasia in asymptomatic adults

BACKGROUND & AIMS

Colonoscopy is the preferred screening test for colorectal neoplasia; the fecal occult blood test (FOBT) detects neoplasias with low levels of sensitivity. Computed tomographic colonography detects neoplasias with high levels of sensitivity but involves exposure to radiation. We investigated whether magnetic resonance colonography (MRC) can be used to screen for colorectal adenomas and cancers.

METHODS

We analyzed data from 286 asymptomatic adults (40-82 years old) who underwent 3 Tesla MRC and colonoscopic examinations on the same day. FOBT was performed before bowel preparation. Colonoscopists were initially blinded to the findings on MRC and unblinded after withdrawal from the respective segments. Sensitivities for adenoma and per-patient sensitivities and specificities were calculated based on the unblinded results of colonoscopy.

RESULTS

We detected 133 adenomas and 2 cancers in 86 patients; 37 adenomas were ≥6 mm, and 20 adenomas were advanced. Sensitivities of MRC and colonoscopy for adenomas ≥6 mm were 78.4% (95% confidence interval [CI], 61.8-90.2) and 97.3% (95% CI, 85.8-99.9); for advanced adenomas these values were 75% (95% CI, 50.9-91.3) and 100% (95% CI, 83.2-100.0), respectively. MRC identified 87.1% (95% CI, 70.2-96.4), colonoscopy 96.8% (95% CI, 83.3-99.9), and FOBT 10.0% (95% CI, 2.1-26.5) of individuals with adenomas ≥6 mm and 83.8% (95% CI, 58.6-96.4), 100% (95% CI, 81.5-100.0), and 17.6% (95% CI, 3.8-43.4) of individuals with advanced neoplasia. Specificities of MRC, colonoscopy, and FOBT for individuals with adenomas ≥6 mm were 95.3% (95% CI, 91.9-97.5), 96.9% (95% CI, 93.9-98.6), and 91.8% (95% CI, 87.6-94.9), respectively.

CONCLUSIONS

3 Tesla MRC detects colorectal adenomas ≥6 mm and advanced neoplasia with high levels of sensitivity and specificity. Although MRC detects colorectal neoplasia with lower levels of sensitivity than colonoscopy, it strongly outperforms one-time FOBT.

New paradigms for colonoscopic management of diminutive colorectal polyps: predict, resect, and discard or do not resect?

The possibility to predict in vivo the histology of colorectal polyps by advanced endoscopic imaging has resulted in the implementation of a more conservative management for diminutive lesions detected at colonoscopy. In detail, a predict-and-do-not-resect strategy has been proposed for diminutive lesions located in the rectosigmoid tract, whilst a predict-resect-and-discard policy has been advocated for nonrectosigmoid diminutive polyps. Recently, the American Society for Gastrointestinal Endoscopy set required thresholds to be met, before allowing the adoption of these policies in the clinical field. The ability of current endoscopic imaging in reaching these thresholds would depend on a complex interaction among the accuracy of advanced endoscopic imaging in differentiating between adenomatous and hyperplastic lesions, the prevalence of (advanced) neoplasia within diminutive lesions, and the type of surveillance intervals recommended. Aim of this review is to summarize the data supporting the application of both a predict-and-do-not-resect and a predict-resect-and-discard policies, also addressing the potential pitfalls associated with these strategies.

Variation in diagnostic performance among radiologists at screening CT colonography

PURPOSE

To assess the variation in diagnostic performance among radiologists at screening computed tomographic (CT) colonography.

MATERIALS AND METHODS

In this HIPAA-compliant, institutional review board-approved study, 6866 asymptomatic adults underwent first-time CT colonographic screening at a single center between January 2005 and November 2011. Results of examinations were interpreted by one of eight board-certified abdominal radiologists (mean number of CT colonographic studies per reader, 858; range, 131-2202). Findings at CT colonography and subsequent colonoscopy were recorded, and key measures of diagnostic performance, including adenoma and advanced neoplasia detection rate, were compared among the radiologists.

RESULTS

The overall prevalence of histopathologically confirmed advanced neoplasia was 3.6% and did not differ significantly among radiologists (range, 2.4%-4.4%; P = .067; P = .395 when one outlier was excluded). Overall, 19.5% of polyps detected at CT colonography proved to be advanced neoplasia and did not differ significantly among radiologists (range, 14.4%-23.2%; P = .223). The overall per-polyp endoscopic confirmation rate was 93.5%, ranging from 80.0% to 97.6% among radiologists (P = .585). The overall percentage of nondiagnostic CT colonographic examinations was 0.7% and was consistent among radiologists (range, 0.3%-1.1%; P = .509).

CONCLUSION

Consistent performance for adenoma and advanced neoplasia detection, as well as other clinically relevant end points, were observed among radiologists at CT colonographic screening.

Variation of adenoma prevalence by age, sex, race, and colon location in a large population: implications for screening and quality programs

BACKGROUND & AIMS

Reliable community-based colorectal adenoma prevalence estimates are needed to inform colonoscopy quality standards and to estimate patient colorectal cancer risks; however, minimal data exist from populations with large numbers of diverse patients and examiners.

METHODS

We evaluated the prevalence of adenomas detected by sex, age, race/ethnicity, and colon location among 20,792 Kaiser Permanente Northern California members ≥50 years of age who received a screening colonoscopy examination (102 gastroenterologists, 2006-2008).

RESULTS

Prevalence of detected adenomas increased more rapidly with age in the proximal colon (adjusted odds ratio [OR], 2.39; 95% confidence interval [CI], 2.05-2.80; 70-74 vs 50-54 years) than in the distal colon (OR, 1.89; 95% CI, 1.63-2.19). Prevalence was higher among men vs women at all ages (OR, 1.77; 95% CI, 1.66-1.89), increasing in men from 25% to 39% at ≥70 years and in women from 15% at 50-54 years to 26% (P < .001). Proximal adenoma prevalence was higher among blacks than whites (OR, 1.26; 95% CI, 1.04-1.54), although total prevalence was similar, including persons <60 years old (OR, 1.17; 95% CI, 0.91-1.50).

CONCLUSIONS

Prevalence of detected adenomas increases substantially with age and is much higher in men; proximal adenomas are more common among blacks than whites, although the total prevalence and the prevalence for ages <60 years were similar by race. These demographic differences are such that current adenoma detection guidelines may not be valid, without adjustment, for comparing providers serving different populations. The variation in prevalence and location may also have implications for the effectiveness of screening methods in different demographic groups.

Incomplete polyp resection during colonoscopy-results of the complete adenoma resection (CARE) study

BACKGROUND & AIMS

Although the adenoma detection rate is used as a measure of colonoscopy quality, there are limited data on the quality of endoscopic resection of detected adenomas. We determined the rate of incompletely resected neoplastic polyps in clinical practice.

METHODS

We performed a prospective study on 1427 patients who underwent colonoscopy at 2 medical centers and had at least 1 nonpedunculated polyp (5-20 mm). After polyp removal was considered complete macroscopically, biopsies were obtained from the resection margin. The main outcome was the percentage of incompletely resected neoplastic polyps (incomplete resection rate [IRR]) determined by the presence of neoplastic tissue in post-polypectomy biopsies. Associations between IRR and polyp size, morphology, histology, and endoscopist were assessed by regression analysis.

RESULTS

Of 346 neoplastic polyps (269 patients; 84.0% men; mean age, 63.4 years) removed by 11 gastroenterologists, 10.1% were incompletely resected. IRR increased with polyp size and was significantly higher for large (10-20 mm) than small (5-9 mm) neoplastic polyps (17.3% vs 6.8%; relative risk = 2.1), and for sessile serrated adenomas/polyps than for conventional adenomas (31.0% vs 7.2%; relative risk = 3.7). The IRR for endoscopists with at least 20 polypectomies ranged from 6.5% to 22.7%; there was a 3.4-fold difference between the highest and lowest IRR after adjusting for size and sessile serrated histology.

CONCLUSIONS

Neoplastic polyps are often incompletely resected, and the rate of incomplete resection varies broadly among endoscopists. Incomplete resection might contribute to the development of colon cancers after colonoscopy (interval cancers). Efforts are needed to ensure complete resection, especially of larger lesions. ClinicalTrials.gov Number: NCT01224444.

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.

Efficacy of computer-aided detection as a second reader for 6-9-mm lesions at CT colonography: multicenter prospective trial

PURPOSE

To assess the effect of computer-aided detection (CAD) as a second reader on the sensitivity and specificity of computed tomographic (CT) colonography in detecting 6-9-mm colorectal cancer (CRC) lesions.

MATERIALS AND METHODS

Individuals with clinical indications for colonoscopy--either for symptoms or as part of participating in a surveillance program or CRC screening--were prospectively enrolled at one of 10 academic centers between July 2007 and May 2009. Institutional review board approval was obtained at each clinical site, and all participants provided written informed consent. All participants underwent CT colonography and colonoscopy on the same day. Experienced readers interpreted the CT colonography images unassisted and then reviewed all colorectal lesion-like structures pinpointed by the CAD algorithm. Segmental unblinding of CT colonoscopy findings at colonoscopy was utilized. The sensitivity and specificity of unassisted and CAD-assisted reading in identifying individuals with 6-9-mm lesions were calculated and compared by means of pairwise analysis.

RESULTS

A total of 618 participants (mean age, 57.9 years; 54.5% male) were included in the final analysis. Of these participants, 464 (75.1%) had no lesions 6 mm or larger, and 52 (8.4%) had 6-9-mm lesions. The sensitivity of CT colonography with unassisted reading and that with CAD-assisted reading in identifying individuals with 6-9-mm lesions was 65.4% (95% confidence interval [CI]: 50.9%, 78.0%) and 76.9% (95% CI: 63.2%, 87.5%; P = .016), respectively. No significant change in specificity was observed: The specificity of CT colonography with unassisted and that with CAD-assisted reading was 91.8% (95% CI: 88.9%, 94.1%) and 90.9% (95% CI: 88.0%, 93.4%; P = .063), respectively. Evaluation of CAD candidates required an additional 1.6 minutes (25th-75th percentile: 1.0 minute to 3.4 minutes).

CONCLUSION

The addition of CAD to reading performed by experienced readers resulted in a significant benefit in the detection of 6-9-mm polyps at CT colonography in this cohort.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120376/-/DC1.

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.

Detection of flat colorectal polyps at screening CT colonography in comparison with conventional polypoid lesions

BACKGROUND

Although the screening of small, flat polyps is clinically important, the role of CT colonography (CTC) screening in their detection has not been thoroughly investigated.

PURPOSE

To evaluate the detection capability and usefulness of CTC in the screening of flat and polypoid lesions by comparing CTC with optic colonoscopy findings as the gold standard.

MATERIAL AND METHODS

We evaluated the CTC detection capability for flat colorectal polyps with a flat surface and a height not exceeding 3 mm (n = 42) by comparing to conventional polypoid lesions (n = 418) according to the polyp diameter. Four types of reconstruction images including multiplanar reconstruction, volume rendering, virtual gross pathology, and virtual endoscopic images were used for visual analysis. We compared the abilities of the four reconstructions for polyp visualization.

RESULTS

Detection sensitivity for flat polyps was 31.3%, 44.4%, and 87.5% for lesions measuring 2-3 mm, 4-5 mm, and ≥6 mm, respectively; the corresponding sensitivity for polypoid lesions was 47.6%, 79.0%, and 91.7%. The overall sensitivity for flat lesions (47.6%) was significantly lower than polypoid lesions (64.1%). Virtual endoscopic imaging showed best visualization among the four reconstructions. Colon cancers were detected in eight patients by optic colonoscopy, and CTC detected colon cancers in all eight patients.

CONCLUSION

CTC using 64-row multidetector CT is useful for colon cancer screening to detect colorectal polyps while the detection of small, flat lesions is still challenging.

Accuracy for optical diagnosis of small colorectal polyps in nonacademic settings

BACKGROUND & AIMS

When small colorectal lesions are accurately characterized, adenomas can be removed and discarded without formal histopathology analysis. Previous studies in an academic setting showed that many lesions can be managed accurately on the basis of their endoscopic image (optical diagnosis). We performed a prospective study to assess the accuracy of optical diagnosis of small colorectal polyps in a nonacademic setting (the DISCOUNT trial) by using high-resolution endoscopy (HRE) and narrow-band imaging (NBI).

METHODS

During colonoscopy, 1 of 3 nonacademic endoscopists characterized small lesions and declared whether this was done with low or high confidence. In cases of high confidence, the endoscopists decided whether lesions should be removed and discarded or whether they could be left in situ. A surveillance interval was then recommended on-site.

RESULTS

Of 215 patients in the study, 108 were found to have 281 small lesions. Of these lesions, 231 were characterized with high confidence by using HRE or NBI; the level of corresponding sensitivity was 77.0% (95% confidence interval, 68.4-83.8), and specificity was 78.8% (95% confidence interval, 70.6-85.2). Of these lesions, 164 were assigned for removal, and 67 were assigned to remain in situ, including 9 adenomas. In 54 patients, a surveillance interval could be recommended on-site that was in line with Dutch guidelines for 44 patients.

CONCLUSIONS

Even though many lesions were characterized by HRE or NBI with high confidence, optical diagnosis in a nonacademic setting proved to be disappointing, with a sensitivity of 77.0% and a specificity of 78.8%. Many lesions were accurately assigned to be removed or remain in situ, although few adenomas were assigned to remain in situ. Also, 19% of on-site recommendations for a surveillance interval proved to be inaccurate.

The risk of advanced histology in small-sized colonic polyps: are non-invasive colonic imaging modalities good enough?

PURPOSE

The study aims to evaluate the risk of advanced histology within small colonic polyps and assess whether this risk warrants different recommendation for surveillance and treatment of such polyps.

METHODS

A retrospective study of all patients undergoing their first ever colonoscopy and polypectomy in a tertiary hospital for one of three indications: screening, positive family history,and positive occult blood in stool. The histological reports of all resected polyps were retrieved and stratified according to the various polyps' sizes. Advanced neoplasia was defined as tubular adenoma ≥10 mm or any size polyp with advanced histology, i.e., villous or tubulovillous adenoma, high-grade dysplasia, intramucosal carcinoma, or invasive cancer.

RESULTS

Seven hundred forty-one patients who had a total of1,192 resected polyps were included. Of polyps ≤5 mm in size, 1.6% harbored invasive cancer or high-grade dysplasia,and additional 4.1% contained villous component. The rate of advanced histology for polyps sized 6-9 mm was over 15%. The rate of advanced histology in polyps ≤5 mm was not significantly different when employing sensitivity analysis accounting for possible under or overestimation of polyp sizes by 1 and 2 mm. However, 4.6% of polyps sized 6-9 mm were found to harbor an invasive or high-grade dysplasia component when taken into account a 2-mm overestimation.

CONCLUSIONS

A non-negligible fraction of small polyps harbor advanced histology. This finding suggests that expectant follow-up by non-invasive colonic imaging modalities for small polyps or not reporting them may put more than 5% of patients at risk of dysplasia progression.

[Korean guidelines for colorectal cancer screening and polyp detection]

Colorectal cancer is the second most common cancer in males and the fourth most common in females in Korea. Since the most of colorectal cancer occur through the prolonged transformation of adenomas into carcinomas, early detection and removal of colorectal adenomas are one of the most effective methods to prevent colorectal cancer. Considering the increasing incidence of colorectal cancer and polyps in Korea, it is very important to establish Korean guideline for colorectal cancer screening and polyp detection. Korean Multi-Society Take Force developed the guidelines with evidence-based methods. Parts of the statements drawn by systematic reviews and meta-analyses. Herein we discussed the epidemiology of colorectal cancers and adenomas in Korea, optimal screening methods for colorectal cancer, and detection for adenomas including fecal occult blood tests, radiologic tests, and endoscopic examinations.

Current status on performance of CT colonography and clinical indications

CT colonography (CTC) is a robust and reliable imaging test of the colon. Accuracy for the detection of colorectal cancer (CRC) is as high as conventional colonoscopy (CC). Identification of polyp is size dependent, with large lesions (≥10mm) accurately detected and small lesions (6-9mm) identified with moderate to good sensitivity. Recent studies show good sensitivity for the identification of nonpolypoid (flat) lesions as well. Current CTC indications include the evaluation of patients who had undergone a previous incomplete CC or those who are unfit for CC (elderly and frail individuals, patients with underlying severe clinical conditions, or with contraindication to sedation). CTC can also be efficiently used in the assessment of diverticular disease (excluding patients with acute diverticulitis, where the exam should be postponed), before laparoscopic surgery for CRC (to have an accurate localization of the lesion), in the evaluation of colonic involvement in the case of deep pelvic endometriosis (replacing barium enema). CTC is also a safe procedure in patients with colostomy. For CRC screening, CTC should be considered an opportunistic screening test (not available for population, or mass screening) to be offered to asymptomatic average-risk individuals, of both genders, starting at age 50. The use in individuals with positive family history should be discussed with the patient first. Absolute contraindication is to propose CTC for surveillance of genetic syndromes and chronic inflammatory bowel diseases (in particular, ulcerative colitis). The use of CTC in the follow-up after surgery for CRC is achieving interesting evidences despite the fact that literature data are still relatively weak in terms of numerosity of the studied populations. In patients who underwent previous polypectomy CTC cannot be recommended as first test because debate is still open. It is desirable that in the future CTC would be the first-line and only diagnostic test for colonic diseases, leaving to CC only a therapeutic role.

Screening for colorectal cancer: what fits best?

Colorectal cancer (CRC) screening has been shown to be effective in reducing CRC incidence and mortality. There are currently a number of screening modalities available for implementation into a population-based CRC screening program. Each screening method offers different strengths but also possesses its own limitations as a population-based screening strategy. We review the current evidence base for accepted CRC screening tools and evaluate their merits alongside their challenges in fulfilling their role in the detection of CRC. We also aim to provide an outlook on the demands of a low-risk population-based CRC screening program with a view to providing insight as to which modality would best suit current and future needs.

Colonoscopy after CT diagnosis of diverticulitis to exclude colon cancer: a systematic literature review

PURPOSE

To estimate the prevalence of underlying adenocarcinoma of the colon in patients in whom acute diverticulitis was diagnosed at computed tomography (CT) and to compare that to the prevalence of colon cancer in the general population.

MATERIALS AND METHODS

A comprehensive literature review was performed to find articles in which patients with CT diagnosis of acute diverticulitis underwent surgery, colonoscopy, or barium enema study within 24 weeks. Patients meeting these criteria were included for analysis. A pooled prevalence of cancer was calculated on the basis of a random effects model and compared qualitatively with the prevalence of cancer in the general population. The 95% confidence intervals around the prevalence of cancer in the study populations were determined.

RESULTS

Ten articles met the inclusion criteria. Data from these articles included only 771 patients who underwent surgery, colonoscopy, or barium enema study within 24 weeks of diagnosis. Fourteen patients were found to have colon cancer, for a prevalence of 2.1% (95% confidence interval: 1.2%, 3.2%). This compares to a calculated estimated prevalence of 0.68% among U.S. adults older than 55 years.

CONCLUSION

There are limited data to support the recommendation to perform colonoscopy after a diagnosis of acute diverticulitis.

Polypectomy rate is a valid quality measure for colonoscopy: results from a national endoscopy database

BACKGROUND

The adenoma detection rate (ADR) is one of the main quality measures for colonoscopy, but it is burdensome to calculate and is not amenable to claims-based reporting.

OBJECTIVE

To validate the correlation between polypectomy rates (PRs) and ADRs by using a large group of endoscopists.

DESIGN

Retrospective study.

SETTING

Community and academic endoscopy units in the United States.

SUBJECTS

Sixty endoscopists and their patients.

MAIN OUTCOME MEASUREMENTS

Proportion of patients with any adenoma and any polyp removed; correlation between ADRs and PRs.

RESULTS

In total, 14,341 screening colonoscopies were included, and there was high correlation between endoscopists' PRs and ADRs in men ( r(s)= .91, P < .0001) and women (r(s) = .91, P < .0001). Endoscopists with PRs in the highest quartile had a significantly higher ADR than did those in the lowest quartile in men (44.6% vs 19.4%, P < .0001) and women (33.6% vs 11.6%, P < .0001). Endoscopists in the top polypectomy quartile also found more advanced adenomas than did endoscopists in the bottom quartile (men: 9.6% vs 4.6%, P = .0006; women: 6.3% vs 3.0%, P = .01). Benchmark PRs of 40% and 30% correlated with ADRs greater than 25% and 15% for men and women, respectively.

LIMITATION

Retrospective analysis of a subset of a national endoscopic database.

CONCLUSIONS

Endoscopists' PRs correlate well with their ADRs. Given its clinical relevance, its simplicity, and the ease with which it can be incorporated into claims-based reporting programs, the PR may become an important quality measure.

Prevalence of colon polyps detected by colonoscopy screening of asymptomatic Hispanic patients

BACKGROUND

Compared with whites, Hispanics have lower incidence of and mortality from colorectal cancer. The purpose of this study was to determine whether asymptomatic Hispanics undergoing colonoscopy screening also have lower age-adjusted incidence of polyps ≥ 10 mm. Such data could be used to formulate future screening guidelines.

AIMS

The objectives of this study were to measure and analyze the prevalence and location of polyps sized ≥ 10 mm in asymptomatic white and Hispanic patients who received colonoscopy screening.

METHODS

Colonoscopy data were prospectively collected from the Clinical Outcomes Research Initiative database, which includes data from a consortium of 66 adult gastrointestinal practice sites in the United States. Asymptomatic white (n = 146,798) and Hispanic (n = 7,654) patients who received colonoscopy screening from 2004 to 2007 were identified. The prevalence of any polyps ≥ 10 mm and of proximal polyps ≥ 10 mm was adjusted for age, sex, practice site type, and family history of colorectal cancer in a multivariate analysis.

RESULTS

There was no significant difference between prevalence of polyps ≥ 10 mm in Hispanic and white patients (5.8% vs. 6.2%; P = 0.11; adjusted OR 0.94; 95% CI 0.85-1.03). There was also no significant difference between prevalence of proximal polyps ≥ 10 mm in Hispanics and whites (adjusted OR 1.05; 95% CI 0.87-1.27).

CONCLUSION

Despite lower incidence of colorectal cancer, the risk of polyps ≥ 10 mm for Hispanic patients undergoing colonoscopy screening is similar to that for whites. These data emphasize the importance of encouraging timely colorectal cancer screening in Hispanics. Our findings support the application of similar recommendations for colorectal cancer screening of Hispanics and whites.