Artificial Intelligence Allows Leaving-In-Situ Colorectal Polyps.

BACKGROUND & AIMS: Artificial Intelligence (AI) could support cost-saving strategies for colonoscopy because of its accuracy in the optical diagnosis of colorectal polyps. However, AI must meet predefined criteria to be implemented in clinical settings. METHODS: An approved computer-aided diagnosis (CADx) module for differentiating between adenoma and nonadenoma in unmagnified white-light colonoscopy was used in a consecutive series of colonoscopies. For each polyp, CADx output and subsequent endoscopist diagnosis with advanced imaging were matched against the histology gold standard. The primary outcome was the negative predictive value (NPV) of CADx for adenomatous histology for ≤5-mm rectosigmoid lesions. We also calculated the NPV for AI-assisted endoscopist predictions, and agreement between CADx and histology-based postpolypectomy surveillance intervals according to European and American guidelines. RESULTS: Overall, 544 polyps were removed in 162 patients, of which 295 (54.2%) were ≤5-mm rectosigmoid histologically verified lesions. CADx diagnosis was feasible in 291 of 295 (98.6%), and the NPV for ≤5-mm rectosigmoid lesions was 97.6% (95% CI, 94.1%-99.1%). There were 242 of 295 (82%) lesions that were amenable for a leave-in-situ strategy. Based on CADx output, 212 of 544 (39%) would be amenable to a resect-and-discard strategy, resulting in a 95.6% (95% CI, 90.8%-98.0%) and 95.9% (95% CI, 89.8%-98.4%) agreement between CADx- and histology-based surveillance intervals according to European and American guidelines, respectively. A similar NPV (97.6%; 95% CI, 94.8%-99.1%) for ≤5-mm rectosigmoids was achieved by AI-assisted endoscopists assessing polyps with electronic chromoendoscopy, with a CADx-concordant diagnosis in 97.2% of cases. CONCLUSIONS: In this study, CADx without advanced imaging exceeded the benchmarks required for optical diagnosis of colorectal polyps. CADx could help implement cost-saving strategies in colonoscopy by reducing the burden of polypectomy and/or pathology. CLINICALTRIALS: gov registration number: NCT04884581.

Effect of Diminutive Adenoma with High-Grade Dysplasia on Surveillance Colonoscopy Interval.

BACKGROUND: Colonoscopy surveillance guidelines set the surveillance schedule based on polyp characteristics. Polyps with high-grade dysplasia (HGD) require 3 years of follow-up regardless of size. However, it is unclear whether patients with diminutive polyps (≤5 mm) with HGD have a higher risk. We evaluated the effect of diminutive adenoma with HGD on adenoma occurrence. METHODS: From January 2015 to December 2017, patients who underwent index and surveillance colonoscopy were retrospectively screened. The patients were grouped into no adenoma group, low-risk (patients with ≤2 low-grade dysplasia [LGD]), diminutive HGD, and high-risk (HGD >5 mm, ≥3 adenomas) groups according to the index colonoscopy results. Each group was analyzed using logistic analysis. RESULTS: The mean follow-up period was 22.47 months. Altogether, 610 (50.45%) patients had LGD and 152 (12.5%) had HGD. Among them, 61 (5.0%) patients had a diminutive polyp with HGD. Analysis of the risks of developing advanced adenoma in the surveillance colonoscopy showed that compared to the no adenoma group, the diminutive HGD group did not show a significant risk (odds ratio [OR] = 1.503 [0.449-5.027], p = 0.509), while the high-risk group showed a significant risk (OR = 2.044 [1.015-4.114], p = 0.045). CONCLUSIONS: Diminutive adenoma with HGD increased the risk of adenoma on surveillance colonoscopy, and in the case of advanced adenoma, the risk was increased, but it was not statistically significant.

Comparison of blue laser imaging and narrow band imaging for the differentiation of diminutive colorectal polyps: A randomized controlled trial.

BACKGROUND: To compare the diagnostic efficacy of blue laser imaging (BLI)- bright and narrow band imaging (NBI) modes of image enhanced endoscopy (IEE) in differentiating neoplastic and non-neoplastic lesions of diminutive colorectal polyps. METHODS: We conducted a prospective randomized controlled trial from September 2015 to July 2016. The participants were randomly assigned (1:1) for colonoscopy with polyp classification under NBI or BLI-bright mode without magnification. Histopathologic diagnosis was used as the gold standard. RESULTS: Three hundred and twenty-four diminutive polyps in 164 patients were included for analysis (BLI: 162 polyps in 73 patients, NBI: 162 polyps in 91 patients). These polyps were located at colon proximal to sigmoid (61.1 and 58.0%) and rectosigmoid colon (38.9 and 42.0%) in the BLI and NBI groups, respectively. Most polyps (71.9%) were adenomatous with one malignant polyp (0.3%). BLI achieved 86.4% accuracy, 98.3% sensitivity, 55.6% specificity, 85.2% positive predictive value (PPV), and 92.6% negative predictive value (NPV), similar to NBI which exhibited 90.1% accuracy, 99.1% sensitivity, 67.4% specificity, 88.5% PPV, and 96.9% NPV in the diagnosis of adenomatous polyps. Based on the location of the polyp, both modes of IEE provided ≥ 95% NPV for diagnosis of adenomatous polyps at the rectosigmoid colon. CONCLUSIONS: BLI-bright and NBI modes of IEE have similar accuracy in differentiation between neoplastic and non-neoplastic lesions of diminutive polyps. Both modes provided ≥ 90% NPV which allows for the adaptation of the American Society of Gastrointestinal Endoscopy "diagnose-and-leave" recommended strategy for diminutive polyps at the rectosigmoid colon.

Endoscopic resection of local recurrences of diminutive polyps by cold forceps polypectomy.

OBJECTIVES: Cold forceps polypectomy (CFP) is an effective treatment for diminutive colorectal polyps. However, polyps occasionally recur, and there is no consensus on their long-term clinical management. Therefore, we investigated the short- and long-term clinical outcomes of re-CFP for recurrent diminutive colorectal polyps. MATERIALS AND METHODS: This was a follow-up of a multicenter, prospective study investigating the clinical outcomes of diminutive colorectal polyps excised by CFP with narrowband imaging-enhanced endoscopy and jumbo forceps. We evaluated short-term outcomes of re-CFP and patients at 1-year follow-up post re-CFP for recurrent colorectal polyps to determine long-term recurrence rates. Additionally, complete resection rates, clinicopathological features, number of forceps bites, and rate of short-term adverse events managed by re-CFP were evaluated. RESULTS: At 1-year follow-up, local recurrence was identified in 18 patients from the original study. The mean size of local recurrent polyps was 1.5 ± 0.6 mm, and all recurrent lesions were < 3 mm. Re-CFP could successfully excise locally recurrent polyps in all cases. All recurrent lesions were low-grade adenomas; no adverse events were reported. Additionally, 16 of 18 patients were evaluated endoscopically at 2-year follow-up; no recurrence was observed. CONCLUSIONS: Recurrent lesions following initial CFP were small and pathologically benign, and re-CFP was an effective treatment.

Computer-Aided Diagnosis of Diminutive Colorectal Polyps in Endoscopic Images: Systematic Review and Meta-analysis of Diagnostic Test Accuracy.

BACKGROUND: Most colorectal polyps are diminutive and benign, especially those in the rectosigmoid colon, and the resection of these polyps is not cost-effective. Advancements in image-enhanced endoscopy have improved the optical prediction of colorectal polyp histology. However, subjective interpretability and inter- and intraobserver variability prohibits widespread implementation. The number of studies on computer-aided diagnosis (CAD) is increasing; however, their small sample sizes limit statistical significance. OBJECTIVE: This review aims to evaluate the diagnostic test accuracy of CAD models in predicting the histology of diminutive colorectal polyps by using endoscopic images. METHODS: Core databases were searched for studies that were based on endoscopic imaging, used CAD models for the histologic diagnosis of diminutive colorectal polyps, and presented data on diagnostic performance. A systematic review and diagnostic test accuracy meta-analysis were performed. RESULTS: Overall, 13 studies were included. The pooled area under the curve, sensitivity, specificity, and diagnostic odds ratio of CAD models for the diagnosis of diminutive colorectal polyps (adenomatous or neoplastic vs nonadenomatous or nonneoplastic) were 0.96 (95% CI 0.93-0.97), 0.93 (95% CI 0.91-0.95), 0.87 (95% CI 0.76-0.93), and 87 (95% CI 38-201), respectively. The meta-regression analysis showed no heterogeneity, and no publication bias was detected. Subgroup analyses showed robust results. The negative predictive value of CAD models for the diagnosis of adenomatous polyps in the rectosigmoid colon was 0.96 (95% CI 0.95-0.97), and this value exceeded the threshold of the diagnosis and leave strategy. CONCLUSIONS: CAD models show potential for the optical histological diagnosis of diminutive colorectal polyps via the use of endoscopic images. TRIAL REGISTRATION: PROSPERO CRD42021232189; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=232189.

Higher risk of advanced histology in adenoma less than 10 mm in fecal immunochemical test screening: Implication for management.

BACKGROUND AND AIM: Whether diminutive or small adenomas detected by fecal immunochemical tests (FITs) are associated with a higher risk of advanced histology remains unknown. We investigated the prevalence of advanced histology in diminutive and small adenomas detected by FIT and compared with that detected by colonoscopy screening. METHODS: We prospectively compared 1860 FIT-positive patients (FIT-positive cohort) and 6691 average-risk patients (screening colonoscopy cohort). Both groups underwent colonoscopies and were shown to have neoplastic lesions. The prevalence of advanced histology was determined, as was the associations with size and FIT positivity. RESULTS: We analyzed 3920 neoplastic lesions from the FIT-positive cohort and 9789 neoplastic lesions from the screening colonoscopy cohort. Eighty (4.3%) diminutive lesions in FIT-positive cohort had advanced histology but without any invasive cancer. Twenty-one patients in the FIT-positive cohort and 49 in the screening colonoscopy cohort with diminutive adenomas displayed advanced histology (3.5% vs 1.2%; adjusted odds ratio [aOR] = 2.99, 95% confidence interval [CI]: 1.77-5.06). Sixteen patients in the FIT-positive cohort (2.7%) with diminutive adenomas might have changed the surveillance interval if a resect-and-discard strategy was applied, with a higher likelihood compared with the screening colonoscopy cohort (aOR = 2.76, 95% CI: 1.53-4.99). CONCLUSIONS: Fecal immunochemical test screening detected more diminutive and small adenomas with advanced histology compared with colonoscopy screening. Its impact on current management of diminutive polyp is limited.

A Rare Report of Hypoplastic Coronary Arteries and Pulmonary Veins: A Case Report and Review of the Literature.

Congenital coronary artery anomalies are estimated to affect about 1% of the general population. Hypoplastic coronary artery disease is an uncommon subset associated with significant mortality regardless whether another major cardiac anomaly is present. In this case report, we present an extremely rare case of an infant with hypoplastic coronary artery disease and hypoplastic pulmonary veins. A literature review pertinent to the clinical findings is also contained herein.

Real-time computer-aided diagnosis of diminutive rectosigmoid polyps using an auto-fluorescence imaging system and novel color intensity analysis software.

Objectives: An endoscopic technique that provides ≥90% negative predictive value (NPV) for differentiating neoplastic polyps is needed for the management of diminutive (≤5 mm) rectosigmoid polyps. This study aimed to assess whether a newly developed software can achieve ≥90% NPV for differentiating rectosigmoid diminutive polyps based on the green-to-red (G/R) ratio, obtained by dividing the green color tone intensity by the red color tone intensity on autofluorescence imaging (AFI). Methods: From December 2017 to May 2018, consecutive patients with known polyps who were scheduled for endoscopic treatment at our institution were prospectively recruited. All colorectal diminutive polyps were differentiated by computer-aided diagnosis using autofluorescence imaging (CAD-AFI) using a novel software-based automatic color intensity analysis; subsequent diagnosis was made by endoscopists based on trimodal imaging endoscopy (TME), which combines AFI, white-light imaging (WLI) and magnifying narrow-band imaging (M-NBI) findings. Thereafter, all polyps were removed endoscopically, and the histopathological diagnosis was evaluated. Results: Ninety-five patients with 258 diminutive rectosigmoid polyps and 171 diminutive non-rectosigmoid polyps were enrolled. Regarding diminutive rectosigmoid polyps, the NPV for differentiating neoplastic polyps was 93.4% (184/197) [95% confidence interval (CI), 89.0%-96.4%] with CAD-AFI and 94.9% (185/195) (95% CI, 90.8%-97.5%) with TME. The accuracy, sensitivity, specificity, and positive predictive value for differentiating diminutive rectosigmoid neoplastic polyps by CAD-AFI were 91.5%, 80.0%, 95.3% and 85.2%, respectively. Conclusions: Real-time CAD-AFI was effective for differentiating diminutive rectosigmoid polyps. This objective technology, which does not require extensive training or endoscopic expertise, can contribute to the effective management of diminutive rectosigmoid polyps.

Management and risk factors for incomplete resection associated with jumbo forceps polypectomy for diminutive colorectal polyps: a single-institution retrospective study.

BACKGROUND: Cold forceps polypectomy is simple and widely used in clinical practice. However, there are concerns about the risk of incomplete resection using this technique. In recent years, it has been reported that polypectomy with jumbo forceps (JF) is an effective treatment modality for diminutive polyps (DPs) because JF are able to remove large tissue samples with the combined advantage of a higher complete histological resection rate for DPs than standard forceps. To our knowledge, no studies have evaluated the risk factors for incomplete resection when polypectomy with JF is performed for DPs. METHODS: From among 1129 DPs resected using JF at Hiroshima City Asa Citizens Hospital between November 2015 and December 2016, we retrospectively evaluated the clinical outcomes of 999 tumors with known histopathology and investigated the relationship between incomplete resection and clinicopathological factors. RESULTS: Most lesions [985 (87%)] were low-grade dysplasia and 14 (1%) were high-grade dysplasia. The en bloc resection rate was 92% (918/999) and the histological en bloc resection rate was 78% (777/999). Multivariate analysis showed that the significant independent predictors of incomplete resection were tumor size ≥ 4 mm [odds ratio (OR) 3.8; 95% confidence interval (CI) 2.65-5.37; p < 0.01], non-tangential direction of forceps in relation to the tumor (OR 1.73; 95% CI 1.21-2.45; p < 0.01), and lack of muscularis mucosae in the pathological specimen (OR 15.7; 95% CI 9.16-27.7; p < 0.01). CONCLUSIONS: This study identified significant independent predictors of incomplete resection of DPs which may be helpful when planning polypectomy with JF.

Long-term results after palliative intra-cardiac repair for tetralogy of Fallot and diminutive pulmonary arteries.

BACKGROUND: In patients with tetralogy of Fallot with the diminutive pulmonary arteries, we sometimes have to give up the complete intra-cardiac repair due to insufficient growth of the pulmonary arteries. We have carried out palliative intra-cardiac repair using a fenestrated patch. METHODS: Of all 202 patients with tetralogy of Fallot in our centre since 1996, five patients (2.5%) with the diminutive pulmonary arteries underwent palliative intra-cardiac repair using a fenestrated patch. Mean operative age was 1.8 years. Previous operation was Blalock-Taussig shunt in 4. At operation, the ventricular septal defect was closed using a fenestrated patch and the right ventricular outflow tract was enlarged. Follow-up period was 9.8 ± 2.6 years. RESULTS: There were no operative and late deaths. Fenestration closed spontaneously on its own in four patients 2.7 ± 2.1 years after the intra-cardiac repair with a stable haemodynamics; however, the last patient with the smallest pulmonary artery index had supra-systemic pressure of the right ventricle post-operatively. The fenestration was emergently enlarged. Systemic arterial oxygen saturation was significantly and dramatically increased from 83.5 to 94% after the palliative intra-cardiac repair, and to 98% at the long term. A ratio of systolic pressure of the right ventricle to the left was significantly decreased to 0.76 ± 0.12 at the long term. Now all five patients were Ross classification class I. CONCLUSION: Although frequent catheter and surgical interventions were needed after the palliative intra-cardiac repair, this repair might be a choice improving quality of life with good results in patients with tetralogy of Fallot associated with the diminutive pulmonary arteries.

Hybrid procedure of right ventricle outflow tract stenting in small infants with pulmonary atresia and ventricular septal defect: early and mid-term results from a single centre.

IntroductionPulmonary atresia, ventricular septal defect, major aorto-pulmonary collateral arteries, and pulmonary arteries hypoplasia are rare and complex congenital defects that require early interventions to relieve cyanosis and enhance the growth of native pulmonary arteries. The treatment of these patients is still controversial. Surgical techniques require cardiopulmonary bypass which is poorly tolerated by small infants. Percutaneous techniques such as radiofrequency perforation can be challenging. The hybrid technique consists of perventricular stenting of the right ventricle outflow tract through medial sternotomy, to restore native pulmonary flow. METHODS: We retrospectively reviewed the cardiovascular database of our centre in order to analyse our experience in hybrid procedure. We detected six patients who underwent hybrid first approach between November 2007 and December 2015. We report our early results and mid-term outcomes. RESULTS: Median age at the procedure was 26 days, median weight was 3150 g, and median Nakata index was 52 mm2/m2. All procedures were successful except for one: this patient underwent a surgical shunt. No immediate and early deaths or major complications occurred and oxygen saturation levels increased in all the patients. Patients were followed up for a period of 12-103 months, and four of them underwent a procedure of unifocalisation at the mean age of 12.5 months. CONCLUSIONS: We reported data from the largest series of patients who underwent this hybrid procedure. Our experience demonstrated encouraging results to expand the use of this approach to bridge high-risk patients with diminutive pulmonary arteries to a second step of surgical repair.

Acquiring diminutive allomorphs: taking item-specific characteristics into account.

Phonological characteristics and frequencies of stems and allomorphs have been explored as possible factors causing differences in production accuracies between allomorphic forms. However, previous findings are not consistent and the relative contributions of these factors are unclear. This study investigated target and erroneous productions of the Dutch diminutive, which has five allomorphs with varying type frequencies and of which the selection depends on the phonological characteristics of the stems. Typically developing children (N = 115, 5;1-10;3) were tested on their production of real and nonce diminutives. Linear mixed effects modelling was used to analyse the data taking nonverbal IQ into account. Type frequencies of the allomorphs and differences in phonological characteristics of the stems were found to be related to differences in production accuracies between the allomorphs. However, phonological characteristics of the stems appeared to have a bigger impact, mainly due to the phonological complexity of these characteristics.

Simplifying Resect and Discard Strategies for Real-Time Assessment of Diminutive Colorectal Polyps.

BACKGROUND & AIMS: During endoscopy, the resect and discard strategy, if performed with high confidence, can be used to determine histologic features of diminutive colorectal polyps (5 mm or less). These polyps can then be removed and discarded without pathology assessment. However, the complexities of real-time optical assessment and follow-up management have provided challenges to widespread use of this approach. We aimed to determine the outcomes of simple alternative strategies, in which all diminutive polyps can be resected and discarded. METHODS: We collected data from 2 previous studies that used narrow-band imaging to assess polyps, performed at 5 medical centers (1658 patients with 2285 diminutive polyps; 15 endoscopists). We compared 3 resect and discard strategies: the currently used optical strategy, which relies on high confidence optical assessment of all diminutive polyps; a location-based strategy that classifies all recto-sigmoid diminutive polyps a priori as hyperplastic and all polyps proximal to the recto-sigmoid colon a priori as neoplastic; and a simplified optical strategy, in which all recto-sigmoid diminutive polyps are classified as hyperplastic unless confidently assessed as neoplastic, and all polyps proximal to the recto-sigmoid colon are classified as neoplastic unless confidently assessed as hyperplastic polyps. The primary outcome was the agreement of the surveillance interval calculated for each strategy with the surveillance interval determined by pathology analysis. RESULTS: The proportion of surveillance intervals that agreed with pathology-based surveillance recommendations was slightly higher when the optical strategy was used compared to the location-based strategy or simplified optical strategy (94% vs 89% and 90%, respectively; P < .001). When the 5-10 year recommendations for patients with low-risk polyps were applied as a 10-year surveillance interval, all 3 strategies resulted in surveillance interval agreement compared to pathology above 90% (the quality benchmark). Use of the simplified or location-based strategy could have avoided pathology analysis for 77% of all polyps, compared to 59% if the optical strategy was used (P < .001). In addition, a higher proportion of patients could receive recommendations immediately after colonoscopy with use of the simplified or location based strategy (65%) compared to the optical strategy (40%) (P < .001). CONCLUSION: A location-based and a simplified optical resect and discard strategy produced surveillance recommendations that were in agreement with those from pathology analysis for at least 90% of patients, assuming a 10-year surveillance interval for patients with low-risk polyps. These strategies could further reduce the number of pathology examinations and provide more patients with immediate surveillance recommendations. Optical assessment might be reduced or might not be required for resect and discard. Clintrials.gov no: NCT01935180 and NCT01288833.

Comparative efficacy of cold polypectomy techniques for diminutive colorectal polyps: a systematic review and network meta-analysis.

BACKGROUND: Although cold polypectomy techniques are preferred over polypectomy with electrocautery in the management of diminutive polyps, comprehensive comparisons among various cold polypectomy techniques have not yet been fully performed. METHODS: We searched for all relevant randomized controlled trials published up until October 2016 examining the efficacy of cold polypectomy techniques for diminutive polyps. Cold polypectomy techniques were classified as cold forceps polypectomy (CFP), jumbo forceps polypectomy (JFP), traditional cold snare polypectomy (CSP), and dedicated CSP, according to the type of device. A network meta-analysis was performed to calculate the direct and indirect estimates of efficacy among the cold polypectomy techniques. RESULTS: Seven studies with 703 patients and 968 polyps were included in the meta-analysis. Regarding comparative efficacy for complete histological eradication, there was no inconsistency in the network (Cochran's Q test, df = 4, P = 0.22; I 2 = 30%). In terms of complete histological eradication, both dedicated and traditional CSP were superior to CFP (odds ratio [OR] [95% confidence interval [CI]] 4.31 [1.92-9.66] and 2.45 [1.30-4.63], respectively); dedicated CSP was superior to traditional CSP (OR [95% CI] 1.76 [1.07-2.89]); and there was no difference between JFP versus CFP (OR [95% CI] 1.36 [0.40-4.61]). Regarding tissue retrieval rate, there was no difference between dedicated versus traditional CSP (OR [95% CI] 1.03 [0.44-2.38]). The procedure time for CSP was comparable to that of CFP. CONCLUSIONS: Dedicated CSP was shown to be superior to other cold polypectomy techniques in terms of complete histological eradication. Cold polypectomy using a dedicated snare can be recommended for the removal of diminutive colorectal polyps.

Linked color imaging improves the visibility of various featured colorectal polyps in an endoscopist's visibility and color difference value.

PURPOSE: Linked color imaging (LCI) by laser endoscopy is a novel narrow band light observation. In this study, we analyzed the efficacy of LCI for improving the various featured colorectal polyp's visibility utilizing a subjective endoscopist's visibility scoring and objective color difference (CD) value. METHODS: We retrospectively reviewed two pictures both with white light (WL) and LCI for 54 consecutive neoplastic polyps 2-20 mm in size. All pictures were evaluated by four endoscopists according to a published polyp visibility score from four (excellent visibility) to one (poor visibility). Additionally, we calculated CD value between each polyp and surrounding mucosa in LCI and WL using an original software. RESULTS: The mean polyp visibility scores of LCI (3.11 ± 1.05) were significantly higher than those of WL (2.50 ± 1.09, P < 0.001). The ratio of an endoscopist's poor visibility (polyp visibility scores 1 and 2) was significantly lower in LCI (27.9%) than WL (55.6%, P < 0.001). With respect to the CD analysis, the CD value of LCI was significantly higher than that of WL (33.3 ± 13.9 vs. 20.7 ± 13.6, P < 0.001). In a subgroup analysis, the polyp visibility scores and CD values of LCI about 24 diminutive polyps (≤5 mm) were higher than those of WL (3.29 ± 0.99 vs. 2.12 ± 0.99, P < 0.001; 31.6 ± 12.8 vs. 14.7 ± 7.6, P < 0.001). Additionally, the polyp visibility scores and CD values of LCI for polyps with any location, size, histology, and morphology were significantly higher than those of WL. CONCLUSIONS: LCI improved the various featured polyp's visibility compared to WL in both polyp visibility scores and CD value.

Treatment outcomes and recurrence following standard cold forceps polypectomy for diminutive polyps.

BACKGROUND: The recurrence rate after standard cold forceps polypectomy (CFP) of diminutive polyps of ≤5 mm has not been fully determined. The aim of this study was to analyze the long-term follow-up results and recurrence rate after CFP of diminutive polyps. METHODS: We retrospectively reviewed the medical records of 884 (738 men; age 53 years) asymptomatic subjects who underwent surveillance colonoscopy after CFP of 1-2 diminutive adenomatous polyps. Cumulative recurrence at the CFP site and risk factors for recurrence were analyzed. RESULTS: Overall recurrence over 59.7 months was 17 % after CFP of 1111 diminutive polyps. The rate of definite recurrence was 4 %, and probable recurrence was 13 %. Recurrence as advanced adenoma was 0.5 % (5/1111). The cumulative probabilities of recurrence at 3, 5, and 7 years after CFP were 10.0, 16.0, and 21.1 %, respectively. Multivariate analysis revealed that polyp 4-5 mm in size and right colonic polyp were risk factors for recurrence (hazard ratio [HR] 1.37; 95 % confidence interval [CI] 1.01-1.86 and HR 1.49; 95 % CI 1.08-2.04, respectively). The recurrence rate for 10 endoscopists who performed at least 50 CFPs ranged from 11.0 to 25.2 %; the probability of recurrence in those in the top half in terms of recurrence rate was 1.6-fold higher than that of those in the bottom half (95 % CI 1.17-2.19). CONCLUSIONS: Although recurrence may develop after standard CFP of diminutive polyps, recurrence as advanced adenoma is rare. Large polyp size, right colon polyp, and endoscopist are risk factors for recurrence after standard CFP.

Risk Factors of Advanced Adenoma in Small and Diminutive Colorectal Polyp.

The aims of this study were to review the clinicopathological characteristics of diminutive (≤ 5 mm) and small polyps (> 5 mm but < 10 mm) and to evaluate the risk factors of advanced adenoma for polyps of diameter < 10 mm in the colon. The medical records of 4,711 patients who underwent first colonoscopy at outpatient clinics or health promotion center were reviewed retrospectively. We analyzed the presence and risk factors of advanced adenoma, which was defined as a villous or tubulovillous polyp, high-grade dysplasia or intramucosal carcinoma histologically. Total 5,058 polyps were detected in the 4,711 patients, and 93.0% (4,704/5,058) polyps were < 10 mm in size. Among them, advanced adenoma was noted in 0.6% (28/4,704) with a villous component in 19, high-grade dysplasia in 3, and adenocarcinoma in 6. Advanced and non-advanced adenomas differed significantly in age group, gender, and polyp size. Multivariate analysis showed that an advanced age (> 65 years), a male gender, and a polyp size of > 5 mm were risk factors of advanced adenoma. The incidence of advanced adenoma in polyps of < 10 mm was 0.6%. Polyp size, male gender, and age of > 65 years are independent risk factors of advanced adenoma.

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

BACKGROUND: Traditional white-light endoscopy cannot reliably distinguish between small (<10 mm) adenomatous and hyperplastic colon polyps. High-definition white-light (HDWL) endoscopy and i-Scan may improve in vivo characterization of small colon polyps. OBJECTIVE: To compare HDWL endoscopy and HDWL plus i-Scan for the assessment of small colon polyps and to measure performance against the American Society for Gastrointestinal Endoscopy (ASGE) thresholds for assessment of diminutive colon polyps. DESIGN: Prospective cohort study. SETTING: Single academic hospital. PATIENTS: Patients undergoing bowel cancer screening colonoscopy. INTERVENTION: In vivo assessment of all polyps <10 mm by using HDWL and i-Scan image enhancement. MAIN OUTCOME MEASUREMENTS: The primary outcome measure was overall diagnostic accuracy of in vivo assessment of colon polyps <10 mm. Secondary outcome measures were sensitivity and specificity for adenomatous histology, negative predictive value for adenomatous histology of diminutive rectosigmoid polyps, and accuracy of prediction of polyp surveillance intervals. RESULTS: A total of 209 polyps in 84 patients were included. There were no significant differences between HDWL endoscopy and i-Scan in characterization of polyps <10 mm (accuracy 93.3% vs 94.7%; P = 1.00; sensitivity 95.5% vs 97.0%; P = .50; specificity 89.3% vs 90.7%; P = 1.00). The negative predictive value for adenomatous histology of diminutive rectosigmoid polyps was 100% with both HDWL endoscopy and i-Scan. U.K. and U.S. polyp surveillance intervals were predicted with 95.2% accuracy with HDWL endoscopy and 97.2% accuracy with i-Scan. LIMITATIONS: Single-center study. CONCLUSION: HDWL endoscopy may be as accurate as HDWL with i-Scan image enhancement for the in vivo characterization of small colon polyps. Both modalities fulfil the ASGE performance thresholds for the assessment of diminutive colon polyps. ( CLINICAL TRIAL REGISTRATION NUMBER: NCT01761279.).

Evaluation of the effectiveness of color intensity analysis using a second-generation autofluorescence imaging system for diminutive colorectal polyp differentiation.

BACKGROUND AND AIM: We previously reported the effectiveness of color tone intensity analysis using autofluorescence imaging (AFI) for distinguishing between colorectal neoplastic and non-neoplastic lesions. Moreover, a second-generation AFI system has become commercially available in Japan. In the present study, we assessed the effectiveness of color tone intensity analysis using a second-generation AFI system for evaluating diminutive colorectal lesions. METHODS: We retrospectively reviewed the cases of 35 consecutive patients with 101 diminutive colorectal lesions that were examined using a second-generation AFI system and resected at the Jikei University Hospital. We estimated the mean green-to-red (G/R) ratio - obtained by dividing the green color tone intensity by the red color tone intensity - of the lesions and compared the values of the neoplastic and non-neoplastic lesions. We also assessed the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the AFI system for neoplastic lesion identification. RESULTS: The mean G/R ratios of the non-neoplastic and neoplastic lesions were 1.06 and 0.87, respectively; the mean G/R ratio significantly differed between the neoplastic and non-neoplastic lesions. Using the second-generation AFI system, neoplastic lesions were identified with a sensitivity, specificity, PPV, and NPV of 94.2%, 91.8%, 92.5%, and 93.8%, respectively. CONCLUSION: Color intensity analysis of diminutive colorectal polyps using the second generation AFI system could effectively distinguish between neoplastic and non-neoplastic lesions.

Natural history of diminutive colorectal polyps: long-term prospective observation by colonoscopy.

BACKGROUND AND AIM: Endoscopic removal of colorectal adenomatous polyps effectively prevents cancer. However, the treatment strategy for diminutive polyps (diameter ≤ 5 mm) remains controversial. Understanding the natural history of diminutive polyps is a prerequisite to their effective management. We prospectively examined the natural history of diminutive polyps by long-term surveillance colonoscopy. METHODS: A total of 207 polyps detected in 112 patients from December 1991 through March 2002 were studied. To avoid potential effects on size and morphological characteristics, all polyps were selected randomly and were followed without biopsy. Polyp size was estimated by comparing the lesion with the diameter of a biopsy forceps. RESULTS: Mean follow up was 7.8 years (SD, 4.8; range, 1.0-18.6; median, 7.5; interquartile range 3.4-11.2). Twenty-four polyps were resected endoscopically, and the histopathological diagnosis was mucosal high-grade neoplasia (Category 4) for one polyp, and mucosal low-grade neoplasia (Category 3) for 23 polyps. Mean linear size of the polyps was 3.2 mm (SD, 1.0; range, 1.3-5.0) at initial colonoscopy and 3.8 mm (SD 1.6; range 1.3-10.0) at final colonoscopy (P<0.01). Left-sided polyps showed a higher growth rate than right-sided polyps, and a type IIIL2 pit pattern was associated with a lower growth rate than a type IIIL1 pattern. CONCLUSION: We clarified the natural history of diminutive polyps by long-term follow-up colonoscopy. The benign course of diminutive polyps should be considered in the design of treatment strategies.