The difference in colon polyp size before and after removal

Risk factors for advanced colorectal neoplasia and colorectal cancer detected at surveillance: a nationwide study in the modern era

AIM

Recommendations for surveillance after colonoscopy are based on risk factors for metachronous advanced colorectal neoplasia (AN) and colorectal cancer (CRC). The value of these risk factors remains unclear in populations enriched by individuals with a positive faecal immunochemical test and were investigated in a modern setting.

METHODS AND RESULTS

This population-based cohort study included all individuals in the Netherlands of ≥55 years old with a first adenoma diagnosis in 2015. A total of 22,471 patients were included. Data were retrieved from the Dutch Nationwide Pathology Databank (Palga). Primary outcomes were metachronous AN and CRC. Patient and polyp characteristics were evaluated by multivariable Cox regression analyses. During follow-up, 2416 (10.8%) patients were diagnosed with AN, of which 557 (2.5% from the total population) were CRC. Adenomas with high-grade dysplasia (hazard ratio [HR] 1.60, 95% confidence interval [CI] 1.40-1.83), villous histology (HR 1.91, 95% CI 1.59-2.28), size ≥10 mm (HR 1.12, 95% CI 1.02-1.23), proximal location (HR 1.12, 95% CI 1.02-1.23), two or more adenomas (HR 1.28, 95% CI 1.16-1.41), and serrated polyps ≥10 mm (HR 1.67, 95% CI 1.42-1.97) were independent risk factors for metachronous AN. In contrast, only adenomas with high-grade dysplasia (HR 2.49, 95% CI 1.92-3.24) were an independent risk factor for metachronous CRC.

CONCLUSIONS

Risk factors for metachronous AN and CRC were identified for populations with access to a faecal immunochemical test (FIT)-based screening programme. If only risk factors for metachronous CRC are considered, a reduction in criteria for surveillance seems reasonable.

Measuring Size of Colorectal Polyps Using a Virtual Scale Endoscope or Visual Assessment: A Randomized Controlled Trial

INTRODUCTION

This study aimed to compare the accuracy of polyp size measurements using a virtual scale endoscope (VSE) with an integrated laser-based adaptive scale function and visual assessment (VA) during colonoscopies.

METHODS

We conducted a single-blinded, prospective randomized controlled trial. Eligible patients (aged 45-80 years) undergoing screening, surveillance, or diagnostic colonoscopies were randomly assigned (1:1) into 2 groups. In the intervention group, all detected polyps were measured for size using VSE; in the control group, all polyps were measured using VA. Size measurements were compared with a reference standard of digital caliper measurement immediately post polypectomy. The primary outcome was the relative accuracy of real-time VSE measurement compared with VA. Secondary outcomes included the mean differences and the correlations between VSE or VA sizes and the reference standard of measurement.

RESULTS

Overall, 230 patients were enrolled and randomized. The relative size measurement accuracy of VSE was 84% in 118 polyps, which was significantly higher than that of VA (105 polyps; 68.4%, P < 0.001). VSE resulted in a significantly higher percentage of size measurements within 25% of true size compared with VA (81.4% vs 41%, P < 0.001). VSE had a significantly lower percentage for >5-mm polyps incorrectly sized as 1-5 mm compared with VA (13.5% vs 57.1%; P < 0.001) and a significantly lower percentage for >3-mm polyps incorrectly sized as 1-3 mm compared with VA (11.3% vs 56.5%; P < 0.001).

DISCUSSION

VSE significantly improves the size measurement accuracy of colorectal polyps during colonoscopies compared with VA and results in fewer misclassifications at relevant decision-making size thresholds.

CT colonography has advantages over colonoscopy for size measurement of colorectal polyps

PURPOSE

The aim of this study was to compare the accuracy of colonoscopy (CS) and CT colonography (CTC) in the measurement of colorectal polyps using pathological size as a reference.

MATERIALS AND METHODS

The analysis included 61 colorectal polyps in 28 patients who underwent preoperative CTC at our institution. All polyps were endoscopically resected. Polyp sizes were measured by CS and CTC. Endoscopic polyp size was extracted from endoscopy records written by one of two endoscopists (A with 11 and B with 6 years of endoscopic experience, respectively), who estimated the size visually/categorically without any measuring devices. After matching the location, the polyp size was measured on CTC using manual three-dimensional (3D) measurement on a workstation. The sizes of resected polyps were also measured after pathological inspection. Differences of the polyp size between CTC and histology, and between CS and histology were compared using paired t tests. Differences in measurement between the two endoscopists were also analyzed.

RESULTS

The mean diameters of polyps measured using CS, CTC, and pathology were 10.5 mm, 9.2 mm, and 8.4 mm, respectively. There was a significant correlation between CS and pathology, as well as between CTC and pathology (both P < 0.0001). The correlation coefficient for CS (r = 0.86) was lower than that for CTC (r = 0.96). The correlations between CS and pathology for endoscopists A and B were 0.90 and 0.89, respectively.

CONCLUSION

Measurements of polyp size using CTC were closer to the pathological measurements compared to those by CS, which exhibited greater variability. This suggests that CTC may be more suitable for polyp size measurements in the clinical setting if patients undergo CTC concurrently with colonoscopy.

Polyp size is associated with colorectal cancer death across histologic polyp subtypes: a retrospective study of a screening colonoscopy registry

BACKGROUND

Surveillance colonoscopy after polyps have been detected at screening aims to reduce the risk for subsequent colorectal cancer, so-called post-colonoscopy colorectal cancer (PCCRC). Inconsistencies exist as to whether the risk should be stratified by histologic subtype. We aimed to compare the risk for PCCRC mortality in screening participants with sessile serrated lesions (SSLs)/traditional serrated adenomas (TSAs), hyperplastic polyps (HPPs), or conventional adenomas.

METHODS

Screening colonoscopy registry data were linked to death registry data between 2010 and 2022. We assessed the association of PCCRC death after a diagnosis of SSL/TSA, conventional adenoma, or HPP by Cox regression, and stratified by polyp size ≥10 and <10 mm.

RESULTS

383,801 participants were included in the analysis. There were 1490 HPPs ≥10 mm (2.6%), compared with 1853 SSL/TSAs (19.6%) and 10,960 conventional adenomas (12.9%). When adjusted for polyp location, the association of polyp size ≥10 mm with PCCRC death was of similar magnitude in participants with conventional adenomas (hazard ratio [HR] 3.68, 95%CI 2.49-5.44), SSL/TSAs (HR 2.55, 95%CI 1.13-5.72), and HPPs (HR 5.01, 95%CI 2.45-10.22). Participants with HPPs mostly died of tumors in the distal colon (54.1%; n = 20), while participants with SSL/TSAs more frequently died of proximal tumors (33.3%; n = 3).

CONCLUSIONS

Across all histologic types, participants with polyps ≥10 mm had at least a two-fold increase in the likelihood of PCCRC death compared with those with polyps <10 mm. These data suggest that size, rather than histologic subtype, should be a determinant for risk stratification after screening colonoscopy.

Endoscopic measurement of the size of gastrointestinal polyps using an electromagnetic tracking system and computer vision-based algorithm

PURPOSE

Polyp size is an important factor that may influence diagnosis and clinical management decision, but estimation by visual inspection during endoscopy is often difficult and subject to error. The purpose of this study is to develop a quantitative approach that enables an accurate and objective measurement of polyp size and to study the feasibility of the method.

METHODS

We attempted to estimate polyp size and location relative to the gastro-oesophageal junction by integrating data from an electromagnetic tracking sensor and endoscopic images. This method is based on estimation of the three-dimensional coordinates of the borders of the polyp by combining the endoscope camera position and the corresponding points along the polyp border in endoscopic images using a computer vision-based algorithm. We evaluated the proposed method using a simulated upper gastrointestinal endoscopy model.

RESULTS

The difference between the mean of ten measurements of one artificial polyp and its actual size (10 mm in diameter) was 0.86 mm. Similarly, the difference between the mean of ten measurements of the polyp distance from the gastroesophageal junction and its actual distance (~ 22 cm) was 1.28 mm. Our results show that the changes in camera positions in which the images were taken and the quality of the polyp segmentation have the most impact on the accuracy of polyp size estimation.

CONCLUSION

This study demonstrated an innovative approach to endoscopic measurements using motion tracking technologies and computer vision and demonstrated its accuracy in determining the size and location of the polyp. The observed magnitude of error is clinically acceptable, and the measurements are available immediately after the images captured. To enhance accuracy, it is recommended to avoid identical images and instead utilise control wheels on the endoscope for capturing different views. Future work should further evaluate this innovative method during clinical endoscopic procedures.

Frequency of endoscopic photodocumentation of large colorectal polyps

BACKGROUND AND AIMS

Colonoscopy quality affects colorectal cancer (CRC) incidence and mortality. The U.S. Multi-Society Task Force on Colorectal Cancer strongly recommends photodocumentation (PD) of lesions ≥10 mm in size (ie, large polyps [LPs]) pre-resection and suggests PD postresection to enhance the quality of colonoscopy. No studies have assessed the frequency of LP PD. We evaluated the frequency of and factors associated with PD of LPs.

METHODS

Reports from endoscopists performing ≥50 colonoscopies with LP resection between 2016 and 2021 were reviewed. The frequency of LP PD pre-resection and post-resection and factors associated with PD were collected. A composite score of 2 quality metrics (PD of completeness of examination and bowel preparation quality) was created. Endoscopists were divided into 2 tiers based on the frequency of the score on all included examinations: Tier 1, ≥95% of examinations; and Tier 2, <95% of examinations. Univariate and multivariate analyses were used to assess factors associated with PD.

RESULTS

A total of 1322 colonoscopies, 1693 LPs, and 25 endoscopists were included in this study. PD of LPs occurred in 1392 (82%) pre-resection and in 878 (52%) post-resection. Factors associated with pre-resection PD include endoscopist subspecialty (colorectal surgery vs gastroenterology: odds ratio [OR], .12; 95% confidence interval [CI], .04-.42); >1 LP on examination (2 vs 1 LP: OR, .41 [95% CI, .27-.61]; and ≥3 vs 1 LP: OR, .41 [95% CI, .24-.70]), and longer withdrawal time (OR, 1.02; 95% CI, 1.01-1.04).

CONCLUSIONS

We provide the first data on PD of LP pre-resection and post-resection, which can inform future benchmarking in this area. The implications of PD on metachronous advanced neoplasia need to be studied.

Usefulness and Educational Benefit of a Virtual Scale Endoscope in Measuring Colorectal Polyp Size

INTRODUCTION

The virtual scale endoscope (VSE) is a newly introduced endoscope that helps endoscopists in measuring colorectal polyp size (CPS) during colonoscopy by displaying a virtual scale. This study aimed to determine the usefulness of the VSE for CPS measurement and the educational benefit of using VSE images to improve CPS estimation accuracy.

METHODS

This study included 42 colorectal polyps in 26 patients treated at Hiroshima University Hospital. In study 1, CPS measured using a VSE before endoscopic mucosal resection was compared with CPS measured on resected specimens, and the agreement between the two measurement methods was evaluated via Bland-Altman analysis. In study 2, 14 endoscopists (5 beginners, 5 intermediates, and 4 experts) took a pre-test to determine the size of 42 polyps. After the pre-test, a lecture on CPS measurement using VSE images was given. One month later, the endoscopists took a post-test to compare CPS accuracy before and after the lecture.

RESULTS

In study 1, Bland-Altman analysis revealed no fixed or proportional errors. The mean bias ±95% limits of agreement (±1.96 standard deviations) of the measurement error was -0.05 ± 0.21 mm, indicating that the agreement between two measurement methods was sufficient. In study 2, the accuracy of CPS measurement was significantly higher among beginners (59.5% vs. 26.7%, p < 0.01) and intermediates (65.2% vs. 44.3%, p < 0.05) in the post-test than in the pre-test.

CONCLUSION

The VSE accurately measures CPS before resection, and its images are useful teaching tools for beginner and intermediate endoscopists.

Estimating the size of colorectal polyps endoscopically: random guess or systematic error?

BACKGROUND

Size of colorectal polyps reflects potential for malignancy and helps define advanced lesions. Studies measuring ability of endoscopists to estimate polyp size show significant variation. The aim of this study was to determine if there is a linear relationship between endoscopic and pathologic polyp size.

METHODS

Data for adenomas removed completely by snare, in one piece, were retrieved from a prospectively recorded polyp database. Endoscopic estimate of maximum diameter was compared to that on the pathology report by linear regression analysis.

RESULTS

There were 126 polyps in 126 patients, 85 men and 41 women. Mean age was 63.2 ± 12.9 years. Mean endoscopic polyp size was 12.2 ± 9.3 mm and mean pathology size was 9.3 ± 6.9 mm. Endoscopically, 16 polyps were ≤ 5 mm, 62 were from 6 to 10 mm, 21 were from 11 to 15 mm, and 27 were from 16 to 55 mm. Twenty-nine polyps were right sided, 86 were left and 11 were rectal. Regression of endoscopic size against pathology size yielded a significant r² of 0.761. Using the regression formula of endoscopic size = 0.7 + 1.175× pathology size an endoscopic estimate of 10 mm (= advanced adenoma) means a pathologic size of 8 mm. For a pathologic size of 10 mm, an endoscopic estimate of 12 mm is needed. A large polyp is ≥20 mm; for this endoscopist a 20 mm polyp is really 16.4 mm.

CONCLUSIONS

The relationship between endoscopic and directly measured size is linear over all polyp diameters, and likely represents a systematic error.

Artificial intelligence-based measurement outperforms current methods for colorectal polyp size measurement

OBJECTIVES

An accurate polyp size estimation during colonoscopy is crucial to determine the surveillance interval and predict the risk of malignant progression. However, there is a high degree of subjectivity in estimating polyp size among endoscopists in clinical practice. We aimed to assess the efficacy of a novel method that uses artificial intelligence (AI) to measure the size of colon polyps and compare it with current approaches.

METHODS

Using the W-Net model for vessel segmentation and based on retinal image datasets (DRIVE, STARE, CHASE-DB, and HRF) and colonoscopy images, we developed the bifurcation-to-bifurcation (BtoB) distance measuring method and applied it to endoscopic images. Measurements were compared with those obtained by eight endoscopists (four expert and four trainees). Diagnostic ability and reliability were evaluated using Lin's concordance correlation coefficients (CCCs) and Bland-Altman analyses.

RESULTS

For both experts and trainees, visually estimated sizes of the same polyp were significantly inconsistent depending on the camera view used (P < 0.001). Bland-Altman analyses showed that there was a trend toward underestimation of the sizes of the polyps in both groups, especially for polyps larger than 10 mm. The new technique was highly accurate and reliable in measuring the size of colon polyp (CCC, 0.961; confidence interval 0.926-0.979), clearly outperforming the visual estimation and open biopsy forceps methods.

CONCLUSION

The new AI measurement method improved the accuracy and reliability of polyp size measurements in colonoscopy images. Incorporating AI might be particularly important to improve the efficiency of trainees at estimating polyp size during colonoscopy.

Factors influencing endoscopic estimation of colon polyp size in a colon model

BACKGROUND/AIMS

Colorectal polyps are removed to prevent progression to colorectal cancer. Polyp size is an important factor for risk stratification of malignant transformation. Endoscopic size estimation correlates poorly with pathological reports and several factors have been suggested to influence size estimation. We aimed to gain insight into the factors influencing endoscopic polyp size estimation.

METHODS

Images of polyps in an artificial model were obtained at 1, 3, and 5 cm from the colonoscope's tip. Participants were asked to estimate the diameter and volume of each polyp.

RESULTS

Fifteen endoscopists from three large-volume centers participated in this study. With an intraclass correlation coefficient of 0.66 (95% confidence interval [CI], 0.62-0.71) for diameter and 0.56 (95% CI, 0.50-0.62) for volume. Polyp size estimated at 3 cm from the colonoscope's tip yielded the best results. A lower distance between the tip and the polyp was associated with a larger estimated polyp size.

CONCLUSION

Correct endoscopic estimation of polyp size remains challenging. This finding can affect size estimation skills and future training programs for endoscopists.

Inflammatory cloacogenic polyps in children: diagnostic yield of rectal retroflexion during colonoscopy

Background and aims

Inflammatory cloacogenic polyps (ICPs) are inflammatory lesions occurring around the anal transitional zone. These are rare in the pediatric population, and most reported cases are found in adults. Therefore, this study aimed to evaluate the usefulness of rectal retroflexion (RR) during colonoscopy in detecting ICPs in children.

Methods

A total of 1837 colonoscopies were performed in 1278 children between September 2003 and August 2020 at the Seoul National University Bundang Hospital. The laboratory test results and colonoscopic and histopathological findings were retrospectively reviewed. ICP was detected using the RR and was diagnosed based on the histologic findings of the polyp.

Results

A total of 69 patients were diagnosed with juvenile polyps (n = 62) or ICP (n = 7), with the latter being detected through RR. All children with ICP were diagnosed from 2013 onwards when RR during colonoscopy came to be routinely performed in our medical center. The patients with ICP were older at diagnosis and more associated with a family history of colorectal polyps than JP. Stool occult blood and the polyps’ endoscopic characteristics, such as number, location, volume, and shape, significantly varied between the two groups. Additionally, there was a statistically significant difference in the polypectomy method. During the long-term follow-up, there was no recurrence of ICP.

Conclusions

Due to their location at the anorectal junction, ICPs may be overlooked during colonoscopy, leading to misdiagnosis. Therefore, a retroflexion view during colonoscopy may help detect ICPs in pediatric patients, especially those presenting with hematochezia.

Accuracy in optical diagnosis for polyps between 5 and 15 mm and its implications on surveillance. A prospective, multicenter study. (POPS study)

BACKGROUND AND AIMS

Polyps histology and diameter up to 1 cm determine whether a patient needs a colonoscopy after 3 years or less, or far ahead. Endoscopists' and pathologists' size estimations can be imprecise. Our aim was to assess endoscopist ability to correctly recommend surveillance colonoscopies for patients with polyps around the 10 mm threshold, based on its endoscopic sizing and optical diagnosis by NBI.

METHODS

NBI-assisted diagnosis and endoscopist estimation of polyp size were compared with reference standard, considering this as the post resection polyp measurements by the nurse assistant and the pathologic results, in a prospective, multicenter, real life study, that recruited adults undergoing colonoscopy in five hospitals. By comparing the endoscopic and pathologist size estimation, with polyps' measurement after resection, and optical and histological diagnoses in patients with polyps between 5 and 15 mm, sensitivity was assessed at the patient level by means of two characteristics: the presence of adenoma, and the surveillance interval. Surveillance intervals were established by the endoscopist, based on optical diagnosis, and by another gastroenterologist, grounded on the pathologic report. Determinants of accuracy were explored at the polyp level.

RESULTS

532 polyps were resected in 451 patients. Size estimation was more precise for the endoscopist. Endoscopist sensitivity for the presence of adenoma or carcinoma was 98.7%. Considering the presence of high-grade dysplasia or cancer, sensitivity was 82.6% for the endoscopic optical diagnosis. Sensitivity for a correct 3-year surveillance interval was 91.5%, specificity 82.3%, with a PPV of 93.2% and NPV of 78.5% for the endoscopist. 6.51% of patients would have had their follow-up colonoscopy delayed, whereas 22 (4.8%) would have it been performed earlier, had endoscopist recommendations been followed.

CONCLUSION

Our study observes that NBI optical diagnosis can be recommended in routine practice to establish surveillance intervals for polyps between 5 and 15 mm.

CLINICAL TRIALS REGISTRATION NUMBER

NCT04232176.

Management of the colonic polyps referred for surgery: an opportunity for improvement

PURPOSE

To examine local practice for non-malignant polyps and to calculate morbidity and mortality associated with bowel resection for this indication.

METHODS

This retrospective cohort study was conducted by reviewing our local gastrointestinal pathology database over a five-year period to identify colonic resections performed for benign polyps. Using search terms "polyp" and "adenoma," 272 cases were identified. Exclusion criteria included: cancer diagnosis, emergency surgeries, multiple resections, and subtotal colectomies for polyposis. 106 patients were included in the study. Primary outcome was perioperative mortality. Secondary outcomes included patient morbidity, characteristics of polyps requiring surgery, and the number of patients referred for a second endoscopic opinion prior to proceeding with surgery.

RESULTS

64 male and 42 female patients with a mean age of 65.3 years (± 8.6 years) underwent colon resection for benign polyps. The mean polyp size was 32.7 mm (± 19.5 mm). 30 patients (28.6%) had polyps equal to or less than 2 cm. Most of the polyps described were sessile (n = 55, 51.9%) and located in the right colon (n = 84, 79.3%). Endoscopic resection was attempted in 31 patients (29.2%), and five cases (4.7%) were referred for a second endoscopic opinion prior to proceeding with surgery. Endoscopists incorrectly felt that polyps were malignant in 62 cases (58.5%). Using Clavien-Dindo classification, most patients had no complications n = 36 (34.0%) or minor complications n = 41 (38.7%). Twelve patients (11.3%) had complications that required antibiotics, blood transfusions, or total parental nutrition. Nine patients (8.5%) required surgical or endoscopic management. Six patients (5.7%) required ICU admission. Mortality rate was 1.9% (n = 2).

CONCLUSION

Surgery for benign colonic polyps is associated with significant morbidity and mortality. These findings reveal a gap in endoscopic management of benign colonic polyps.

Underwater vs Conventional Endoscopic Mucosal Resection of Large Sessile or Flat Colorectal Polyps: A Prospective Randomized Controlled Trial

BACKGROUND & AIMS

Conventional endoscopic mucosal resection (CEMR) with submucosal injection is the current standard for the resection of large, nonmalignant colorectal polyps. We investigated whether underwater endoscopic mucosal resection (UEMR) is superior to CEMR for large (20-40mm) sessile or flat colorectal polyps.

METHODS

In this prospective randomized controlled study, patients with sessile or flat colorectal polyps between 20 and 40 mm in size were randomly assigned to UEMR or CEMR. The primary outcome was the recurrence rate after 6 months. Secondary outcomes included en bloc and R0 resection rates, number of resected pieces, procedure time, and adverse events.

RESULTS

En bloc resection rates were 33.3% in the UEMR group and 18.4% in the CEMR group (P = .045); R0 resection rates were 32.1% and 15.8% for UEMR vs CEMR, respectively (P = .025). UEMR was performed with significantly fewer pieces compared to CEMR (2 pieces: 45.5% UEMR vs 17.7% CEMR; P = .001). The overall recurrence rate did not differ between both groups (P = .253); however, subgroup analysis showed a significant difference in favor of UEMR for lesions of >30 mm to ≤40 mm in size (P = .031). The resection time was significantly shorter in the UEMR group (8 vs 14 minutes; P < .001). Adverse events did not differ between both groups (P = .611).

CONCLUSIONS

UEMR is superior to CEMR regarding en bloc resection, R0 resection, and procedure time for large colorectal lesions and shows significantly lower recurrence rates for lesions >30 mm to ≤40 mm in size. UEMR should be considered for the endoscopic resection of large colorectal polyps.

Factors associated with inaccurate size estimation of colorectal polyps: A multicenter cross-sectional study

BACKGROUND AND AIM

Accurate polyp size estimation is essential in deciding the therapeutic strategy of colorectal polyps and endoscopic surveillance intervals. However, many endoscopists frequently make incorrect size estimations without being aware of their errors. This cross-sectional study aimed to clarify the characteristics of endoscopists associated with inaccurate estimation.

METHODS

We previously conducted a web trial involving 261 endoscopists in 51 institutions in Japan to assess their ability to estimate polyp size. Participants answered questions about polyp size using visual estimates in a test involving images of 30 polyps. Here, we investigated the relationships between inaccurate size estimation and the backgrounds of participants. The rates of overestimation and underestimation of polyp size were also compared to clarify any trends in the answers of participants with low accuracy (< 50%).

RESULTS

Multivariable logistic regression analysis revealed that the number of colonoscopic procedures in the past year was the only factor associated with a low accuracy of polyp size estimation (odds ratio 0.750, 95% confidence interval 0.609-0.925; P = 0.007). Endoscopists with low accuracy had a greater tendency to overestimate polyp size (42.3% overestimation and 21.2% underestimation, P < 0.001) compared with other endoscopists (16.6% overestimation and 17.9% underestimation, P = 0.951).

CONCLUSIONS

Endoscopists with limited experience of colonoscopy in the past year were more likely to make frequent errors in size estimation. Furthermore, endoscopists making inaccurate size estimations had a propensity to overestimate polyp size.

Short educational video to improve the accuracy of colorectal polyp size estimation: Multicenter prospective study

BACKGROUND AND AIM

Accurate polyp size estimation is necessary for appropriate management of colorectal polyps. Polyp size is often determined by subjective visual estimation in clinical situations; however, it is inaccurate, especially for beginner endoscopists. We aimed to clarify the usefulness of our short training video, available on the Internet, for accurate polyp size estimation.

METHODS

We conducted a multicenter prospective controlled study in Japan. After completing a pretest composed of near and far images of 30 polyps, participants received the educational video lecture (<10 min long). The educational content included the knowledge of strategies based on polyp size and criteria for size estimation including the endoscopic equipment size and videos of polyps in vivo. After one month, the participants undertook a posttest. The primary outcome was a change in the accuracy of polyp size visual estimation between the pretest and posttest in beginners.

RESULTS

Participants including 111 beginners, 52 intermediates, and 97 experts from 51 institutions completed both tests. Accuracy of polyp size estimation in the beginners showed a significant increase after the video lecture [54.1% (51.3-57.0%) to 59.0% (56.5-61.5%), P = 0.003]. Multivariable logistic regression analysis showed that the category of beginners and a low score on pretest (P = 0.020 and <0.001, respectively) were the factors that contributed to an increase of ≥10% in the accuracy.

CONCLUSION

Our educational video led to an improvement in polyp size estimation in beginners. Furthermore, this video may be useful for non-beginners with insufficient polyp size estimation accuracy.

Accuracy of estimation of polyp size at colonoscopy

BACKGROUND

The Cancer Council posits that the size of adenomas is a more robust marker of risk than histological characteristics. The purpose of our study is to assess the accuracy of estimation of polyp size at colonoscopy amongst different levels of endoscopists and compare this with histopathological size.

METHODS

A retrospective review of prospectively collected data was performed. Specimens were included if they were (i) from patients aged 18 years or older, (ii) polyp obtained at colonoscopy, (iii) measured in quantitative units and (iv) the largest eligible polyp per patient.

RESULTS

A total of 92 patients were included. Our results demonstrate that the relationship between the histological size of a polyp and an endoscopist's estimate depended upon seniority level (P = 0.001). Senior consultants tended to overestimate lesion size (P < 0.001), fellows/junior consultants tended to underestimate size (P = 0.010), whilst registrars' estimates demonstrated no systematic difference from histological size (P = 0.518). The ratio of a senior consultant's estimate of polyp size to histological size was on average 74% with their estimates ranging from 31% to 173%. The corresponding estimates are 123% (32-470%) for fellows/junior consultants and 107% (35-334%) for registrars.

CONCLUSION

Our study demonstrates that senior consultants are more precise with more junior endoscopists having a great degree of variability in their practice. It is evident that there is a relationship between proceduralist experience and polyp size estimation. It is, therefore, important to consider the ways in which we can mitigate this learning curve and continue to develop technology to improve our accuracy.

Polyp Characteristics of Nonsyndromic and Potentially Syndromic Juvenile Polyps: A Retrospective Cohort Analysis

BACKGROUND

Juvenile polyps (JPs) are the most common gastrointestinal polyps diagnosed in children. There is paucity of evidence differentiating polyp burden groups and the presence and significance of neoplastic changes.

METHODS

A retrospective chart review of patients, ages birth through 18 years with nonsyndromic JPs was performed from 2003 to 2017. Abstracted data included basic demographics, age, clinical presentation, colonoscopy findings, and pathology report. Slides of polyps with neoplasia were reviewed by a pathologist.

RESULTS

A total of 213 subjects underwent 326 procedures and 435 polypectomies. Subjects with positive family history, positive gene mutations, or numerous (>10) polyps were excluded. Groups were defined by polyp number (1, 2-4, 5-10). Polyp recurrence on repeat colonoscopy was significantly related to polyp burden (1 polyp: 1.5%/2-4 polyps 19.2%/5-10 polyps 82.6%: P < 0.001). Polyp distribution was significantly different amongst different groups with isolated polyps favoring a distal distribution. JPs harboring adenomatous foci were reported in 26 (12%) patients. JPs harboring adenomatous foci were significantly more likely to be proximally distributed but the presence of adenomatous transformation within the polyps did not correlate with polyp number or the likelihood of polyp recurrence on repeat colonoscopy.

CONCLUSIONS

JP recurrence is positively and significantly related to polyp burden. JP harbored adenomatous changes independent of polyp number, underscoring a possible malignant potential in JPs. In the absence of a consistent genotype or pedigree, the presence of adenomatous transformation within JPs cannot be construed as a biomarker for syndromic juvenile polyposis.

Comparison of Underwater vs Conventional Endoscopic Mucosal Resection of Intermediate-Size Colorectal Polyps

BACKGROUND & AIMS

Endoscopic mucosal resection (EMR) with submucosal injection is an established method for removing colorectal polyps, although the en bloc resection rate decreases when polyp size exceeds 10 mm. Piecemeal resection increases local recurrence. Underwater EMR (UEMR) is an effective technique for removal of sessile colorectal polyps and we investigated whether it is superior to conventional EMR (CEMR).

METHODS

We conducted a multicenter randomized controlled trial at 5 institutions in Japan. Patients with endoscopically diagnosed, intermediate-size (10-20 mm) sessile colorectal lesions were randomly assigned to undergo UEMR or CEMR. Only the most proximal lesion was registered. The UEMR procedure included immersion of the entire lumen in water and snare resection of the lesion without submucosal injection of normal saline. We analyzed outcomes of 108 colorectal lesions in the UEMR group and 102 lesions in the CEMR group. R0 resection was defined as en bloc resection with a histologically confirmed negative resection margin. The primary endpoint was the difference in the R0 resection rates between groups.

RESULTS

The proportions of R0 resections were 69% (95% confidence interval [CI] 59%-77%) in the UEMR group vs 50% (95% CI 40%-60%) in the CEMR group (P = .011). The proportions of en bloc resections were 89% (95% CI 81%-94%) in the UEMR group vs 75% (95% CI 65%-83%) in the CEMR group (P = .007). There was no significant difference in median procedure time (165 vs 175 seconds) or proportions of patients with adverse events (2.8% in the UEMR group vs 2.0% in the CEMR group).

CONCLUSIONS

In a multicenter randomized controlled trial, we found that UEMR significantly increased the proportions of R0 resections for 10- to 20-mm sessile colorectal lesions without increasing adverse events or procedure time. Use of this procedure should be encouraged. Trials registry number: UMIN000018989.

Risk of metachronous advanced lesions after resection of diminutive and small, non-advanced adenomas

BACKGROUND AND AIMS

Current post-polypectomy surveillance interval guidelines do not discriminate between 1-2 diminutive (1-5mm) and small (6-9mm) non-advanced adenomas. This study compared the risk for metachronous advanced lesions in these groups.

METHODS

Patients with 1-2 diminutive, non-advanced adenomas and no further advanced lesions, and patients with no polyps at baseline colonoscopy were retrospectively analyzed to determine the rate of metachronous advanced lesions. These were defined as the combined rate of colon cancer, advanced adenoma and ≥ 3 non-advanced adenomas at surveillance colonoscopy. Polyp size was measured either subjectively by the endoscopist or by pathology-based measurements.

RESULTS

Among patients with diminutive (n = 395) and small polyps (n = 110), advanced lesions were found in 68 patients (17.2%) and 16 patients (14.5%), respectively (P = 0.53), during a mean follow-up of 4.3 ± 0.9 years. In contrast, advanced lesions were observed in 33 patients (6.6%) in the no polyp group (n = 505), significantly lower than diminutive (P = 0.000) and small polyp groups (P = 0.002), despite a mean follow-up duration of 6.1 ± 1.9 years. The rate of metachronous advanced lesions was also similar between patients with 1-3mm polyps (16%) versus 7-9mm polyps (15.8%).

CONCLUSIONS

Our findings suggest that among patients who underwent polypectomy of up to 2 non-advanced adenomas, those with diminutive and small polyps have the same risk of metachronous advanced lesions; thus, supporting uniform recommendations for surveillance colonoscopy for these lesions.

Reproducibility and accuracy of visual estimation of polyp size in large colorectal polyps

BACKGROUND

Previous studies indicate that visual size estimation (in situ) of polyp size tends to differ from postfixation measurements, which effects allocation to surveillance intervals. Little is known about interobserver variation of in-situ measurements of large polyps. The primary objective was to assess interobserver variation of in situ measurements of large colorectal polyps. Secondary objectives were the agreement of in situ measurements with postfixation measurements, and the agreement on detection of ≥20 mm polyps between these measurements.

MATERIAL AND METHODS

Interobserver variability of in situ polyp size measurements was assessed between a diagnostic colonoscopy and the secondary therapeutic colonoscopy by dedicated endoscopists, in patients that were referred for an advanced polypectomy. After excision pre- and postfixation polyp sizes were measured with a ruler in three dimensions.

RESULTS

A total of 40 patients, with 45 polyps, were included in the study. The average difference between the two in situ measurements was 2.4 mm (95% confidence interval (CI): -0.4-5.2). The differences between the first in situ, second in situ and pre-fixation measurement in comparison to postfixation measurements were 1.8 mm (95% CI: -1.2-4.9), 0.1 mm (95% CI: -1.5-1.8) and 1.0 mm (95% CI: -0.2-2.2). Cohen's Kappa on detection of ≥20 mm polyps in agreement with postfixation measurements was 0.65 in the primary and 0.88 in the secondary in situ measurements.

CONCLUSION

This study shows a variation between in situ size measurements of large polyps. Improvements in daily clinical routines can be made by using an instrument to compare polyp size with and refraining from rounding sizes up or down. A randomized controlled trial assessing which instruments should be used for in-situ measurements of large polyps is warranted, in order to optimize size measurements of large colorectal polyps.

Addressing priority challenges in the detection and assessment of colorectal polyps from capsule endoscopy and colonoscopy in colorectal cancer screening using machine learning

BACKGROUND

Colorectal capsule endoscopy (CCE) is a potentially valuable patient-friendly technique for colorectal cancer screening in large populations. Before it can be widely applied, significant research priorities need to be addressed. We present two innovative data science algorithms which can considerably improve acquisition and analysis of relevant data on colorectal polyps obtained from capsule endoscopy.

MATERIAL AND METHODS

A fully paired study was performed (2015-2016), where 255 participants from the Danish national screening program had CCE, colonoscopy, and histopathology of all detected polyps. We developed: (1) a new algorithm to match CCE and colonoscopy polyps, based on objective measures of similarity between polyps, and (2) a deep convolutional neural network (CNN) for autonomous detection and localization of colorectal polyps in colon capsule endoscopy.

RESULTS AND CONCLUSION

Unlike previous matching methods, our matching algorithm is able to objectively quantify the similarity between CCE and colonoscopy polyps based on their size, morphology and location, and provides a one-to-one unequivocal match between CCE and colonoscopy polyps. Compared to previous methods, the autonomous detection algorithm showed unprecedented high accuracy (96.4%), sensitivity (97.1%) and specificity (93.3%), calculated in respect to the number of polyps detected by trained nurses and gastroenterologists after visualizing frame-by-frame the CCE videos.

Variation between Pathological Measurement and Endoscopically Estimated Size of Colonic Polyps

Background and Aims

Accurate determination of colonic polyp size is vital to an appropriate surveillance. The main aim of this study was to evaluate variation between the polyp size reported by the endoscopist and its pathological measurement.

Methods

A retrospective analysis of all colonic adenomatous polyps resected in a 12-month period was performed at our center. Endoscopic and pathological size for each polyp were compared, and overestimation rates, underestimation rates, and endoscopic-pathological variation (EPV) were calculated.

Results

Among the 573 polyps that were included, the mean endoscopic and pathological sizes were 8.00 and 6.66 mm, respectively. The most frequent error, in 62.1%, was overestimation by the colonoscopist. Overestimation and EPV were associated with resection technique (higher in endoscopic mucosal resection and smaller with biopsy forceps) and colonoscopist. They were not associated with years of experience in colonoscopy. Overestimation was more frequent in larger polyps.

Conclusions

Our study shows significant discordance between endoscopic and pathological size of colonic polyps with a clear tendency for endoscopic overestimation. Larger polyps are more difficult to accurately assess than smaller ones. This propensity for error was not related to colonoscopist's years of experience and seems to be an individual tendency.

Mis-sizing of Adenomatous Polyps is Common among Endoscopists and Impacts Colorectal Cancer Screening Recommendations

Background/Aims

To determine the accuracy of identifying ≥6-mm adenomatous polyps during colonoscopy and define its impact on subsequent interval screening.

Methods

We conducted a retrospective study of patients who underwent colonoscopies at Banner University Medical Center, Tucson from 2011 to 2015. All patients with ≥6-mm adenomatous polyps based on their colonoscopy report were included. Adenomatous polyps were excluded if they did not meet the criteria. Discrepancies in the polyp size were determined by calculating the percentage of size variation (SV). Clinical mis-sizing was defined as SV >33%.

Results

The polyps analyzed were predominantly <10 mm in size. Approximately 13% of the examined polyps met the inclusion criteria, and 40.7% of the adenomas were ≥10 mm. A total of 189 ≥6-mm adenomatous polyps were collected from 10 different gastroenterologists and a colorectal surgeon. Adenomatous polyps were clinically mis-sized in 56.6% of cases and overestimated in 71.4%. Among the adenomas reviewed, 22% of mis-sized polyps and 11% of non-mis-sized polyps resulted in an inappropriate surveillance interval.

Conclusions

We found that more than half of ≥6-mm adenomatous polyps are mis-sized and that there is a tendency to overestimate adenoma size among endoscopists. This frequently leads to inappropriate intervals of surveillance colonoscopy.

Surveillance after positive colonoscopy based on adenoma characteristics

BACKGROUND

Patients with adenomatous polyps are at increased risk for developing colorectal cancer based on the characteristics and number of polyps, but less is known about the individual and combined contribution of these factors. This study aimed to better characterize the risk of advanced adenoma and cancer in patients with positive baseline colonoscopy.

METHODS

Patients who had polyps at baseline colonoscopy were included in this retrospective cohort study (N=1165) and were categorized into 6 groups: (1) 1-2 non-advanced adenomas (NAA's), (2) ≥3 NAA's, (3) advanced tubular adenoma, (4) small tubulovillous adenoma (TVA), (5) large TVA and (6) multiple advanced adenomas (MAA's). Findings at surveillance colonoscopy were documented in each group.

RESULTS

The combined incidence of advanced adenoma,  ≥3 NAA's, and colorectal cancer at surveillance colonoscopy was significantly higher in the baseline large TVA (29.2%) than small TVA groups (13.5%, P<0.001), as well as in the MAA's group (44.1%) compared with large TVA group (P=0.02). The incidence of colorectal cancer, however, was not significantly different between the groups.

CONCLUSIONS

The size of the polyp and the number of advanced lesions are more important than its histology for predicting the risk of high-risk metachronous lesions at follow-up.

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.

Endoscopic overestimation of colorectal polyp size

BACKGROUND AND AIMS

Polyp size ≥ 1 cm triggers more frequent colonoscopic surveillance, yet size is typically based on subjective endoscopic estimates. We sought to compare contemporary assessments of polyp size by endoscopic estimation and pathology measurement.

METHODS

Colonoscopy and pathology reports were reviewed from the 2012 medical records at a large institution. Only polyps resected in toto with both endoscopic estimates and pathology measurements were included. Pathology measurements were considered the criterion standard. Factors affecting endoscopic miscall rates were assessed by multivariate analyses.

RESULTS

From 6067 polyps resected, both endoscopic and pathology sizes were available on 1528. Distribution of polyp size appraised by endoscopy but not by pathology revealed modal clustering, particularly around 1 cm. Among 99 polyps endoscopically called 1 cm, 72% were <1 cm on pathology. Of all 222 polyps estimated as ≥ 1 cm on endoscopy, 46% were <1 cm on pathology; of 1306 polyps estimated as <1 cm, 3.9% were ≥ 1 cm on pathology. By histology, 39% of adenomatous, 59% of sessile serrated, and 73% of hyperplastic polyps were overcalled; P = .008. By configuration, 34% of pedunculated, 49% of sessile, and 61% of flat polyps were overcalled; P = .014. Endoscopic overestimation was more common in women (54%) than in men (40%) (P = .03) and with proximal (56%) than distal (40%) sites; P = .02. Miscall rates were unaffected by endoscopist covariates.

CONCLUSIONS

Substantial discordance exists between endoscopic and pathology-based assessments of polyp size. Almost half of polyps called advanced on endoscopic estimates of size ≥ 1 cm fell below this threshold on actual pathology measurements.

Accuracy of endoscopists’ estimate of polyp size: A continuous dilemma

AIM: To examine the discrepancy, if any, between the endoscopist’s estimate and pathologist’s measurement of colonic polyp size.

METHODS: We retrospectively studied 88 patients who underwent colonoscopy with a clear unequivocal documentation of polyp size by both endoscopist and pathologist. Endoscopist measurements were based on the visual estimate of polyp size seen on high definition screens. The measurement was done by our pathologists after formalin fixation. We compared the endoscopist estimate of the polyp size to the pathologist measurement in order to explore the discordance between the two readings. Data regarding demographics and method of polypectomy (snare polypectomy vs excisional biopsy) was collected, as well. Statistical analysis software (SAS) was used to analyze the data.

RESULTS: Our cohort included 88 patients from which 111 polyps were removed. Fifty-two (46.8%) of the 111 polyps were excised using biopsy forceps and fifty-nine (53.2%) were removed by snare. In the biopsy forceps group, the mean polyp size documented by the pathologist was 0.38 ± 0.19 cm and the mean polyp size documented by the endoscopist was 0.54 ± 0.16 cm. The mean difference was 0.16 cm (P < 0.001). In the snare group, the mean polyp size documented by the pathologist was 0.54 ± 0.24 cm and the mean polyp size documented by the endoscopist 0.97 ± 0.34 cm. The mean difference was 0.43 cm (P < 0.001). Combining both groups, the mean size documented by pathologist was 0.46 ± 0.23 cm compared to 0.76 ± 0.35 cm documented by the endoscopist. The mean difference was 0.3 cm (95%CI: 0.23-0.36).

CONCLUSION: Post polypectomy measurement by the pathologist are generally smaller than the endoscopist’s estimate.

Usefulness of a novel calibrated hood to determine indications for colon polypectomy: visual estimation of polyp size is not accurate

PURPOSE

Accurate measurement of polyp size during colonoscopy is important because the size is a surrogate marker of cancer, but a standardized measurement technique to measure polyp size has yet to be determined. We have developed a new device "a novel calibrated hood." We assessed polyp size by visual estimation and measurement using the calibrated hood.

METHODS

Patients who underwent polypectomy from November 2012 to September 2013 and who had received screening colonoscopy within 6 months prior to the polypectomy were included in this study. Polypectomy was performed attaching the calibrated hood. The endoscopist measured the polyp size using the calibrated hood. Polyp size was compared between visual estimation and measurement using the calibrated hood.

RESULTS

Seventy-five patients with 157 polyps were included. Seventy-seven polyps fulfilled the selection criteria. Mean polyp size by visual estimation was 6.57 ± 2.15, and by using calibrated hood was 5.94 ± 1.73 (p = 0.005). There was a significant difference between measurements using the calibrated hood vs. visual estimation by inexperienced trainees; however, there was no difference in case of well-experienced endoscopists. By visual estimation, 11 of 19 polyps were decided for ≥5 mm despite being less than 5 mm, and 5 of 58 polyps were decided for <5 mm despite being 5 mm or larger in diameter.

CONCLUSION

Visual estimation of polyp size is not accurate. It is important to measure the size by an objective way, and the calibrated hood is useful in measuring polyp size, from the standpoint of accurately determining indication for polypectomy.

Measurement system that improves the accuracy of polyp size determined at colonoscopy

AIM: To assess the accuracy of polyp size using an endoscopic lesion measurement system (ELMS).

METHODS: The accuracy of polyp size assessment was compared among measurements acquired by visual estimation, disposable graduated biopsy forceps (DGBF; used as a “scale-plate”) and the ELMS.

RESULTS: There were 192 polyps from 166 cases included in this study. The mean diameter of the post polypectomy measurement was 0.85 ± 0.53 cm (range: 0.2-3.0 cm). The mean diameter by visual estimation was 1.10 ± 0.53 cm, which was significantly different compared to the actual size of the polyp (P < 0.001). The mean diameters obtained using DGBF (0.87 ± 0.54 cm) and ELMS (0.85 ± 0.53 cm) did not significantly differ from the actual size of the polyp. The difference between the measurements from the ELMS and DGBF was not significant.

CONCLUSION: Unlike visual estimations at colonoscopy, endoscopic graduated biopsy forceps and the endoscopic lesion measurement system are accurate methods to estimate polyp size.

Use of disposable graduated biopsy forceps improves accuracy of polyp size measurements during endoscopy

AIM: To determine the accuracy of endoscopic polyp size measurements using disposable graduated biopsy forceps (DGBF).

METHODS: Gradations accurate to 1 mm were assessed with the wire of disposable graduated biopsy forceps. When a polyp was noted, endoscopists determined the width of the polyp; then, the graduated biopsy forceps was inserted and the largest diameter of the tumor was measured. After excision, during surgery or endoscopy, the polyp was measured using the vernier caliper.

RESULTS: One hundred and thirty-three colorectal polyps from 119 patients were studied. The mean diameter, by post-polypectomy measurement, was 0.92 ± 0.69 cm; 83 were < 1 cm, 36 were between 1 and 2 cm, and 14 were > 2 cm. The mean diameter, by visual estimation, was 1.15 ± 0.88 cm; compared to the actual size measured using vernier calipers, the difference was statistically significant. The mean diameter measured using the DGBF was 0.93 ± 0.68 cm; compared to the actual size measured using vernier calipers, this difference was not statistically significant. The ratio between the mean size estimated by visual estimation and the actual size was significantly different from that between the mean size estimated using the DGBF and the actual size (1.26 ± 0.30 vs 1.02 ± 0.11).

CONCLUSION: The accuracy of polyp size estimation was low by visual assessment; however, it improved when the DGBF was used.

The correlation between endoscopic and histopathological measurements in colorectal polyps

AIMS

Colorectal adenomas measuring 10 mm or more are at increased neoplastic risk and therefore undergo more rigorous follow-up. Currently there is no standardized method of assessing polyp size. We aimed to examine the correlation between endoscopic and histopathological measurements to determine the most appropriate method for clinical use.

METHODS AND RESULTS

Colorectal polyps removed between November 2008 and January 2009 were identified. Routine endoscopic and histopathological measurements were determined retrospectively from the reports. Glass slide measurements using a ruler and magnified graticule were performed prospectively on all cases. Fifty cases also underwent high-resolution digital scanning and tissue morphometry. After exclusions, 352 polyps from 210 patients were identified, including 235 adenomas, 107 hyperplastic polyps and 10 other lesions. Only 89% of adenomas had a documented endoscopic measurement and 22% a histopathological measurement. The median endoscopic measurement was significantly greater, resulting in 13% of patients being misclassified as high or low risk.

CONCLUSIONS

There are significant differences between endoscopic and histopathological measurement, and currently histopathologists frequently fail to accurately measure adenomas. Histopathological measurement should still be considered as the gold standard; however, there must be a hierarchy of measurements to take account of the practical limitations of sample fragmentation.

Variation in polyp size estimation among endoscopists and impact on surveillance intervals

BACKGROUND

Accurate estimation of polyp size is important because it is used to determine the surveillance interval after polypectomy.

OBJECTIVE

To evaluate the variation and accuracy in polyp size estimation among endoscopists and the impact on surveillance intervals after polypectomy.

DESIGN

Web-based survey.

PARTICIPANTS

A total of 873 members of the American Society for Gastrointestinal Endoscopy.

INTERVENTIONS

Participants watched video recordings of 4 polypectomies and were asked to estimate the polyp sizes.

MAIN OUTCOME MEASUREMENTS

Proportion of participants with polyp size estimates within 20% of the correct measurement and the frequency of incorrect surveillance intervals based on inaccurate size estimates.

RESULTS

Polyp size estimates were within 20% of the correct value for 1362 (48%) of 2812 estimates (range 39%-59% for the 4 polyps). Polyp size was overestimated by >20% in 889 estimates (32%, range 15%-49%) and underestimated by >20% in 561 (20%, range 4%-46%) estimates. Incorrect surveillance intervals because of overestimation or underestimation occurred in 272 (10%) of the 2812 estimates (range 5%-14%). Participants in a private practice setting overestimated the size of 3 or of all 4 polyps by >20% more often than participants in an academic setting (difference = 7%; 95% confidence interval, 1%-11%).

LIMITATIONS

Survey design with the use of video clips.

CONCLUSION

Substantial overestimation and underestimation of polyp size occurs with visual estimation leading to incorrect surveillance intervals in 10% of cases. Our findings support routine use of measurement tools to improve polyp size estimates.

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.

Endoscopic measurement of polyp size using a novel calibrated hood

Background. Although the size of colon polyps is an important risk factor for colorectal cancer, a standardized measurement technique has yet to be determined. In clinical practice, most endoscopists estimate polyp size by uncertain visual estimation; however, colonoscopic polypectomy is indicated for adenomatous polyps more than 5 mm in diameter. We have therefore developed a novel calibrated hood that enables accurate measurement of polyp size during colonoscopy. Method. We compared prepolypectomy estimates using the calibrated hood against measurements of preformalin-fixed samples immediately after polypectomy. Results. Sixty-five polyps removed from 44 patients were included in the present study. The mean size of polyps was significantly larger at prepolypectomy (6.06 ± 1.23 mm) than after polypectomy (5.48 ± 1.31 mm, P < 0.05). Conclusion. Accurately measuring the size of polyps during colonoscopy is important, since polyps are shrunk by polypectomy. Attaching the calibrated hood appears useful in the measurement of polyp size to determine indications for polypectomy in patients with colon polyps.

Variable interpretation of polyp size by using open forceps by experienced colonoscopists

BACKGROUND

Endoscopic measurement of colorectal polyps by using open forceps is commonly used in clinical trials but is subject to several sources of error.

OBJECTIVE

Assess error rates in polyp size determination with open forceps at the step of measurement after the forceps are aligned on the polyp.

DESIGN

This was a prospective assessment of 49 gastroenterologists who received training on 10 photographs of polyps with aligned forceps and then measured 10 additional test polyps from photographs. One of the test photographs was excluded because of incorrect forceps alignment.

SETTING

Data analyzed at an academic medical center.

INTERVENTION

Photographs displayed in a webinar.

MAIN OUTCOME MEASUREMENTS

Description of rates of accurate measurements, including the fraction correct within 50% and 25% margins of error.

RESULTS

A total of 37% of all measurements were correct to the exact millimeter, 34% were larger, and 29% smaller compared with the reference standard. A total of 47 of 49 doctors measured all 9 polyps within 50% of the reference standard, and 21 measured all 9 correctly within a 25% error margin.

LIMITATIONS

Other potential sources of error in open forceps measurement were not evaluated.

CONCLUSION

Open forceps polyp size determination is subject to error at the step of using the fully aligned forceps as a scale for measurement. A margin of error of 50% up or down is needed to prevent this step in size determination from causing errors in polyp matching in clinical trials comparing diagnosis-only imaging to colonoscopy.

Endoscopic estimation of tumor size in early gastric cancer

BACKGROUND

Although the accurate estimation of tumor size is essential for proper patient selection for endoscopic resection in early gastric cancer (EGC), no study has been conducted to date on tumor size estimation. We aimed to evaluate the accuracy of endoscopic visual estimation of tumor size of EGC.

METHODS

In 508 EGC patients that underwent endoscopic resection, endoscopic visual estimations were performed retrospectively by independent two endoscopists using still images. Data were compared with pathologic measurements as gold standard. Inter-observer agreement was determined using the Bland-Altman method and intra-class correlation coefficients (ICC). Measurement discrepancies were presented as differences between measurements.

RESULTS

The ICC between the two endoscopists was 0.915 (95 % CI 0.900-0.928). Mean endoscopic estimates for both endoscopists were significantly lower than mean pathologic measurements (1.50 and 1.67 vs. 1.80 cm, P < 0.001). Absolute differences between average endoscopic estimates and pathologic measurements were found to be acceptable in most cases: an absolute difference of <0.4 cm was found for 80 % (404/508) of cases. Bland-Altman plot showed that 94 % of cases lay within the 95 % limits of agreement. Measurement discrepancy was proportional to tumor size and increased for an undifferentiated histology.

CONCLUSIONS

Endoscopic visual estimations were found to show reliable agreement with pathologic measurement in EGC patients undergoing endoscopic resection, together with good inter-observer agreement. Further prospective study is needed to confirm the validity of this method.

Features of adenoma and colonoscopy associated with recurrent colorectal neoplasia based on a large community-based study

BACKGROUND & AIMS

We investigated adenoma and colonoscopy characteristics that are associated with recurrent colorectal neoplasia based on data from community-based surveillance practice.

METHODS

We analyzed data of 2990 consecutive patients (55% male; mean age 61 years) newly diagnosed with adenomas from 1988 to 2002 at 10 hospitals throughout The Netherlands. Medical records were reviewed until December 1, 2008. We excluded patients with hereditary colorectal cancer (CRC) syndromes, a history of CRC, inflammatory bowel disease, or without surveillance data. We analyzed associations among adenoma number, size, grade of dysplasia, villous histology, and location with recurrence of advanced adenoma (AA) and nonadvanced adenoma (NAA). We performed a multivariable multinomial logistic regression analysis to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

During the surveillance period, 203 (7%) patients were diagnosed with AA and 954 (32%) patients with NAA. The remaining 1833 (61%) patients had no adenomas during a median follow-up of 48 months. Factors associated with AA during the surveillance period included baseline number of adenomas (ORs ranging from 1.6 for 2 adenomas; 95% CI: 1.1-2.4 to 3.3 for ≥5 adenomas; 95% CI: 1.7-6.6), adenoma size ≥10 mm (OR = 1.7; 95% CI: 1.2-2.3), villous histology (OR = 2.0; 95% CI: 1.2-3.2), proximal location (OR = 1.6; 95% CI: 1.2-2.3), insufficient bowel preparation (OR = 3.4; 95% CI: 1.6-7.4), and only distal colonoscopy reach (OR = 3.2; 95% CI: 1.2-8.5). Adenoma number had the greatest association with NAA. High-grade dysplasia was not associated with AA or NAA.

CONCLUSIONS

Large size and number, villous histology, proximal location of adenomas, insufficient bowel preparation, and poor colonoscopy reach were associated with detection of AA during surveillance based on data from community-based practice. These characteristics should be used jointly to develop surveillance policies for adenoma patients.

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.

Endoscopic mis-sizing of polyps changes colorectal cancer surveillance recommendations

BACKGROUND

Adenomatous polyps greater than 1 cm are defined as advanced adenomas. Inaccurate size estimation can lead to inappropriate surveillance recommendations of colorectal adenomas.

OBJECTIVE

The aim of this study was to determine the impact of endoscopic polyp mis-sizing on colorectal cancer surveillance recommendations.

DESIGN

This is a prospective study.

SETTING

This study was conducted in a gastroenterology practice at a US academic medical center.

PATIENTS

Patients undergoing colorectal cancer screening and surveillance colonoscopies from 2010 to 2011 were included.

MAIN OUTCOME MEASUREMENTS

Endoscopic size estimates of polyps 10 to 25 mm were compared with postfixation histopathologic polyp measurements for 15 different gastroenterologists. Only adenomatous polyps removed in entirety by snare polypectomy were included in the analysis. Size variation was defined as (endoscopic estimate - histopathologic size)/(histopathologic size). Clinical mis-sizing was defined as a size variation of >33%. The mean size variation, the percentage of clinical mis-sizing, and the percentage of inappropriate surveillance recommendation due to size variation >33% were reported per endoscopist.

RESULTS

: Included for analysis were 4990 procedures from 15 gastroenterologists. A total of 230 polyps from 200 patients met inclusion criteria. The average age was 62.6 years (SD 10.1), and 52% were men. The mean size variation between the endoscopic polyp size estimation and the histopathologic polyp was 73.6% (range of mean size variation, 13%-127%). 62.6% (range, 0%-91%) of included polyps had clinical mis-sizing. Of included polypectomies, 35.2% (range, 0%-67%) resulted in an inappropriate surveillance recommendation due to clinical mis-sizing even after considering histology and synchronous polyps.

LIMITATIONS

This was a single-center study.

CONCLUSIONS

There is marked variation in endoscopists' ability to accurately size adenomatous polyps. Some endoscopists rarely mis-size adenomas, and their surveillance recommendations are appropriate in regard to sizing. However, other endoscopists inaccurately size adenomas, and this leads to inappropriate surveillance of colorectal polyps. In this study, approximately 1 of 3 included polypectomies yielded inappropriate surveillance recommendations because of clinical mis-sizing.

Impact of a family history of colorectal cancer on the prevalence of advanced neoplasia at colonoscopy in 4,967 asymptomatic patients

BACKGROUND AND AIMS

A family history of colorectal cancer is considered an independent risk factor for advanced neoplasia at colonoscopy. The expected outcome for screening colonoscopy in patients with a family history is not well established in all populations.

METHODS

We designed a large, prospective study of an unselected population in San Diego, California to assess the impact of a family history of colorectal cancer on the prevalence of advanced neoplasia on screening colonoscopy.

RESULTS

We evaluated 6,905 consecutive patients referred for colonoscopy between January 2005 and December 2006. Of the 4,967 who met the inclusion criteria, the mean age was 58.8 and consisted of 58.6% women. Overall 930 (18.7%) had neoplasia and 249 (5%) had advanced neoplasia, eight (0.16%) of which were cancer. The 4,967 patients were divided into 643 with and 4,324 without a family history of colorectal cancer. Of the 643 patients with a family history, 38 (5.9%) had advanced neoplasia, one of which was cancer. Of the 4,324 patients without a family history, 211 (4.9%) had advanced neoplasia including seven cancers. The relative risk for finding advanced neoplasia in patients with a single affected first degree relative was 1.21 (95% CI, 0.87-1.69; P = 0.31).

CONCLUSIONS

A family history of one first-degree relative with colorectal cancer did not predict a significantly higher prevalence of advanced neoplasia at screening colonoscopy in this Southwestern cohort.

Polyps with advanced neoplasia are smaller in the right than in the left colon: implications for colorectal cancer screening

BACKGROUND & AIMS

Colonoscopy is consistently associated with reduced left-sided, but not right-sided, colorectal cancer (CRC) incidence and mortality. This might be because polyps with advanced pathology are smaller and more easily missed in the right vs left colon. We explored this postulate by evaluating the relationship among size, location, and histology of polyps from a large nationwide sample.

METHODS

We conducted a cross-sectional study of 233,414 polyps from 142,686 patients (47% women; mean age, 60 years), which were reviewed by Miraca Life Sciences in 2009. We assessed polyp histology, location, and size of largest fragment submitted. We compared size distribution of right vs left polyps with high-grade dysplasia (HGD) or adenocarcinoma as well as any advanced neoplasia.

RESULTS

The average size of right-sided polyps was smaller than that of left-sided polyps with HGD or adenocarcinoma (8.2 vs 12.4 mm, respectively); the same was true for polyps with advanced neoplasia (7.6 vs 11.1 mm, respectively) (P < .001). Most right-sided polyps with HGD, adenocarcinoma, or any advanced neoplasia were ≤9 mm, whereas most left-sided polyps with these findings were >9 mm. Polyps with advanced pathology were 5-fold more likely to be <6 mm in the right vs left colon: odds ratio, 5.27; 95% confidence interval, 4.06-6.82 for HGD or adenocarcinoma; odds ratio, 4.89; 95% confidence interval, 4.34-5.51 for advanced neoplasia.

CONCLUSIONS

Polyps with features of HGD, adenocarcinoma, or advanced neoplasia were significantly smaller in the right vs left colon. Strategies to prevent right-sided CRC require more accurate detection of small, advanced polyps.

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.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prospective blinded comparison of polyp size on computed tomography colonography and endoscopic colonoscopy

BACKGROUND & AIMS

The size of polyps found on computed tomography colonography (CTC) has been suggested as the major determinant of patient management. We compared polyp size as seen on CTC with endoscopic visualization, in vivo probe measurement, and ex vivo size before and after fixation.

METHODS

Polyps measured on CTC sent for endoscopic removal were evaluated for polyp size in a blinded fashion by endoscopic estimation, in vivo probe measurement, and after removal.

RESULTS

Fifty-six polyps were included in the study. There was no significant difference between CTC polyp size, real-time colonoscopy size estimation, or probe measurement. The size of polyp measured immediately ex vivo and after pathology fixation was significantly smaller. Management would be altered in 6 of 56 polyps (10.7%) on the basis of differences between size of the polyp on endoscopy and CTC.

CONCLUSIONS

(1) CTC polyp size measurement is not significantly different from colonoscopy in vivo visual estimation and linear probe measurement. (2) Differences in size of polyps as measured on CTC and endoscopy will affect patient management in 10% of cases.

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

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

Endoscopists' estimation of size should not determine surveillance of colonic polyps

OBJECTIVE

Current British Society of Gastroenterology guidelines use adenomatous polyp size as one of the key factors in determining polyp follow-up. This study aimed to compare polyp size assessment by colonoscopists and pathologists before and after fixation to determine the optimal method for measurement.

METHOD

Thirty-five colorectal polyps were found during pre-arranged colonoscopies in one centre. Polyp size was measured to the nearest 1 mm by three different methods: 1. by the endoscopist at colonoscopy; 2. by the pathologist fresh, following removal; 3. by the pathologist fixed, following fixation. The endoscopist and the pathologist were blinded to each other's measurements.

RESULTS

Seventeen men, eighteen women with mean age of 66.2 years (SD: 9.4, range: 38.7-85.5) underwent polypectomy/s with all polyps removed intact. Polypectomies were performed by consultants (43%), nurse specialists (34%) and specialist registrars (23%). The median size (mm) of polyps measured were endoscopically, 6.5 (2-25 mm); fresh specimen 7.0 (4-28 mm) and fixed 7.0 (4-28 mm). Endoscopic measurements were significantly lower than that of fresh and fixed sizes (P < 0.001 and P = 0.003 respectively), with poor correlation [correlation of variance (CV): 21.0% and intraclass correlation coefficient (ICCC): 0.841 for endoscopic and fresh measurements; CV: 21.1% and ICCC: 0.838 for endoscopic and fixed measurements]. There was no statistical difference between fresh and fixed specimen measurements (P > 0.05; CV: 4.2%, ICCC: 0.974). In three patients, the endoscopic measurement was < 1 cm in polyps that were found to be >or= 1 cm on pathological measurement.

CONCLUSIONS

Endoscopists consistently underestimated polyp size. Fixation had no effect on polyp size. Pathologists' measurement of polyp size on fixed specimens should determine the need for further colonoscopic follow-up.

An endoscopic training model to improve accuracy of colonic polyp size measurement

PURPOSE

Most studies of colonic polyps rely on visual estimation when regarding polyp size; however, the reliability of a visual estimate is questionable. Our study aims to develop a training model to improve the accuracy of size estimation of colonic polyps in vivo.

METHODS

Colon polyps were recorded on 160 video clips during colonoscopy. The size of each polyp was estimated by visual inspection and subsequently measured with a flexible linear measuring probe. The study included a pretest, an intervention, and a posttest. The pretest included 160 video clips, which comprised the visual-estimation portion of the study. The intervention was an educational model consisting of 30 video clips which included a visual-estimation section and a linear-measuring-probe section, designed to help the endoscopists to compare their visual estimate of size with the measured size of the polyps. The posttest included the 160 video clips used in the pretest, presented in random order. Intraobserver agreement and diagnostic accuracy were compared before and after the training session.

RESULTS

Eight beginners and four experienced colonoscopists were enrolled. The overall kappa (kappa) values of intraobserver agreement for pretest and posttest were 0.74 and 0.85 for beginner group as well as 0.83 and 0.88 for experienced group, respectively. The overall diagnostic accuracy improved from 0.52 to 0.78 for beginner group and 0.71 to 0.87 for experienced group (P < 0.05) after education with the training model.

CONCLUSIONS

This training model could help endoscopists improve the accuracy of measurement of polyps on colonoscopy in a short period. The durability of learning effect needs further investigation.

Current techniques in the performance, interpretation, and reporting of CT colonography

The technical objective of computed tomographic colonography (CTC) is to acquire high-quality computed tomography images of the cleansed, well-distended colon for polyp detection. In this article the authors provide an overview of the technical components of CTC, from preparation of the patient to acquisition of the imaging data and basic methods of interpretation. In each section, the best evidence for current practices and recommendations is reviewed. Each of the technical components must be optimized to achieve high sensitivity in polyp detection.