Introduction

The Resect and Discard strategy allows endoscopists to replace post-polypectomy pathology with real-time prediction of polyp histology during colonoscopy (optical diagnosis). The present systematic review and meta-analysis investigated how implementation of computer-aided diagnosis (CADx) for polyp pathology affected this optical diagnosis procedure.

Aims & Methods

We conducted a search of MEDLINE, EMBASE, and Scopus databases, covering studies published from inception to February 20, 2024. We included histologically verified accuracy diagnostic studies that evaluated the real-time optical diagnosis performance of CADx systems for polyps ≤5mm in the entire colon. The aim was to estimate the potential benefits and harms associated with integrating CADx assistance into the endoscopist optical diagnosis, both before and after its implementation. The primary outcomes were the proportion of polyps that would have avoided pathological assessment (main benefit) and the proportion of polyps incorrectly predicted (main harm) due to false-positive or -negative optical diagnosis. Only diagnosis with a high-level of confidence were considered.

Results

A total of 11 studies with 7,400 polyps were eligible for analysis, providing stand-alone performance of CADx with sensitivity and specificity in identifying adenomatous histology of 87% (95% confidence interval [CI]: 0.82, 0.91) and 75% (95% CI: 0.68, 0.82), respectively. Three studies (4,086 polyps) were included to analyze the primary benefit/harm outcome measures. There was no significant difference between the CADx-unassisted and CADx-assisted strategies for the proportion of polyps that would have avoided pathological assessment (90% vs. 90%; risk ratio: 1.01; 95% CI: 0.99, 1.04; I²=53.49%; moderate certainty evidence). CADx-assisted strategy reduced the proportion of incorrectly predicted polyps as compared with CADx-unassisted (13% vs. 12%; risk ratio: 0.88; 95% CI: 0.79, 0.98; I²=0%; moderate certainty evidence) mainly due to a decrease in false-positive diagnosis.

Conclusion

CADx implementation did not result in clinically relevant benefits for the Resect-and-Discard strategy.

Disclosure

Cesare Hassan: Fujifilm Co. (consultancy); Medtronic Co. (consultancy), Yuichi Mori: Olympus Corp (consultancy, speaking honorarium, equipment loan); Cybernet System (ownership interest), Alessandro Repici: Fujifilm Co. (consultancy); Olympus Corp (consultancy); Medtronic Co. (consultancy).

Introduction

Computer-aided diagnosis (CADx) allows the real-time prediction of polyp histology during colonoscopy based on their appearance. This systematic review aims to compare the diagnostic performance of two future CADx utilization: the autonomous CADx strategy (CADx-alone) and the endoscopist with CADx assistance strategy (CADx-assisted).

Aims & Methods

We searched MEDLINE, EMBASE, and Scopus databases published before 20 March 2024. We screened for histologically-verified accuracy diagnostic studies that compared the real-time optical diagnosis performance of CADx-alone strategy versus CADx-assisted strategy for polyps ≤5mm. Only high confidence optical diagnosis were condsidered for the CADx-assisted optical diagnosis. A random effect model was used to calculated the pooled sensitivity, specificity, negative predictive value, positive predictive value and accuracy. Two separate analyses were performed: one on polyps in the whole colon and another restricted to rectosigmoid polyps.

Results

The analysis was based on seven studies. The entire colon, included 5,765 polyps for CADx-alone and 5,009 polyps for CADx-assisted; CADx-alone showed a significant reduction in sensitivity (88% vs. 93%; RR: 0.95; 95% CI: 0.92, 0.99; I²: 79.46%), negative predictive value (NPV) (85% vs. 90%; RR: 0.94; 95% CI: 0.91, 0.98; I²: 74.96%), PPV (81% vs. 83%; RR: 0.98; 95% CI: 0.96, 1.00; I²: 0%) and overall accuracy (84% vs. 86%; RR: 0.96; 95% CI: 0.95, 0.98; I²: 0%). However, there was no significant difference in specificity (74% vs. 75%; RR: 0.98; 95% CI: 0.94, 1.02; I²: 55.78%). When the analysis was restricted to rectosigmoid polyps, which included 2,515 polyps evaluated by CADx-alone and 2,153 by CADx-assisted, CADx-alone showed significantly lower specificity (83% vs. 85%; RR: 0.97; 95% CI: 0.95, 1.00; I²: 26.36%), PPV (73% vs. 79%; RR: 0.94; 95% CI: 0.89, 1.00; I²: 15.50%) and overall accuracy (86% vs. 88%; RR: 0.97; 95% CI: 0.95, 0.98; I²: 0%). No significant difference was observed in sensitivity (87% vs. 92%; RR: 0.96; 95% CI: 0.92, 1.01; I²: 33.60%) and NPV (94% vs. 95%; RR: 0.99; 95% CI: 0.97, 1.00; I²: 0%)

Conclusion

Our findings show that autonomous CADx failed to reach the CADx-assisted sensitivity, NPV, PPV and accuracy in the whole colon. When restricted to rectosigmoid polyps, autonomous CADx failed to reach specificity, PPV and accuracy. These findings underscore the necessity for further enhancements in the autonomous CADx diagnostic performance and the need for further studies that investigate the human-machine interaction.

Disclosure

Cesare Hassan: Fujifilm Co. (consultancy); Medtronic Co. (consultancy), Yuichi Mori: Olympus Corp (consultancy, speaking honorarium, equipment loan); Cybernet System (ownership interest), Alessandro Repici: Fujifilm Co. (consultancy); Olympus Corp (consultancy); Medtronic Co. (consultancy).

Introduction

Colorectal cancer (CRC) is the third most common cancer and the second cause of cancer-related deaths worldwide [1]. Although the biological pathways that transform the normal colon tissue into malignant tissue are different, polyps are presumed to be the precursor lesions for malignant tumors in all cases[2]. Colorectal polyps (CRP) can be seen in various forms or shapes on colonoscopy. Convolutional neural networks (CNNs) are a class of deep neural networks used for different clinical purposes, including improving the detection rate of colorectal lesions.

Aims & Methods

This systematic review and meta-analysis aimed to assess the performance of CNN-based models in the detection or classification of colorectal polyps (CRP) and colorectal cancer (CRC). A systematic search was performed in MEDLINE, SCOPUS, Web of Science, and other related databases. The performance measures of the CNN models in the detection of CRP and CRC were calculated in the two scenarios of the best and worst accuracy. Stata and R software were used for conducting the meta-analysis.

Results

From 3368 searched records, 24 primary studies were included. The sensitivity and specificity of CNN models in predicting CRP in worst and best scenarios ranged fr3om 84.7-91.6% and 86.0-93.8%, respectively. These values in predicting CRC varied between 93.2-94.1% and 94.6-97.7%. The positive and negative likelihood ratios varied between 6.2-14.5 and 0.09-0.17 in these scenarios, respectively, in predicting CRP, and 17.1-41.2 and 0.07-0.06 in predicting CRP. The diagnostic OR and accuracy measures of CNN models in predicting CRP in worst and best scenarios ranged between 36-162 and 80.5-88.6%, respectively. These values in predicting CRC in the worst and the best scenarios varied between 239.63-677.47 and 88.2-96.4%. The area under the ROC varied between 0.92 to 0.97 in the worst and the best scenarios in CRP, respectively, and 0.98 to 0.99 in CRP prediction.

Conclusion

CNN-based models showed an acceptable accuracy in detecting CRP and CRC.

References

1. Keum NN, Giovannucci E. Global burden of colorectal cancer: emerging trends, risk factors and prevention strategies. Nat Rev Gastroenterol Hepatol 2019;16:713-732.
2. Øines M, Helsingen LM, Bretthauer M, Emilsson L. Epidemiology and risk factors of colorectal polyps. Best Pract Res Clin Gastroenterol 2017;31: 419–24.

Disclosure

Not to declare

Introduction

Histopathological assessment remains the gold standard for evaluating diminutive colorectal polyps, despite the potential of optical diagnosis (OD) to reduce colonoscopy-associated costs (1). However, implementing OD strategies remains limited in clinical practice (2). This study aimed to evaluate patient acceptance of truly replacing pathology evaluation of diminutive polyps with resect and discard (RD) and diagnose and leave (DL) strategies using computer-aided polyp diagnosis (CADx).

Aims & Methods

In this prospective clinical pilot study at the Montreal University Hospital Center, 102 patients undergoing colonoscopy were invited to participate in the study. Patients received information on CADx, RD, DL and were informed that if they agree to participate in the study, we will diagnose all polyps using CADx during the colonoscopy, but polyps will be discarded or left in place and no pathology exams will be performed. For consenting patients, blue light imaging (BLI)-assisted CADx was used and endoscopists made the final histology determination and rated their confidence level (high vs. low) in the OD. Endoscopists also determined if high-risk features were present before using RD or DL strategies. Then all diminutive polyps optically diagnosed with high confidence as adenomas were resected and discarded and all diminutive rectosigmoid polyps optically diagnosed as hyperplastic with high confidence were left in situ. All polyps >5mm, with disagreement between endoscopists and CADx OD, low-confidence OD, or high-risk features (JNET 2b or higher) were sent for pathology evaluation. All cases were video recorded, and a quality review of the diagnoses performed with two expert endoscopists (DR and HP).

Results

Among the 102 patients approached, 97 (95%) accepted participating and utilization of CADx instead of pathology. Three stated that they did not want to participate in any research, and two patients stated that they did not trust OD or CADx as the reason for refusal. Overall, 164 diminutive polyps were removed in 97 patients (mean age=67.2 years), of which 36% were in the rectosigmoid and 64% in the proximal colon. CADx-assisted OD was performed on 97% of the polyps. The proportion of polyps with a low-confidence OD or disagreement between endoscopists' and CADx-based OD was 19/159 (11.9%). Overall, 98/159 (61.6%) polyps underwent the RD strategy, of which 4 polyps were discarded by the endoscopist's discretion despite disagreement between endoscopists and CADx OD. One of these 4 polyps had to undergo the DL strategy but was RD because of serrated features. One polyp in the proximal colon was resected and retrieved because of serrated features. 40 polyps were DL in the rectosigmoid, of which 1 polyp was neoplastic based on CADx and endoscopist's OD.

Conclusion

We observed a very high patient acceptance for truly replacing diminutive polyp histopathology with CADx-assisted OD. CADx-based OD was used to RD 98/159 (61.6%) or DL 40/159 (25.2%) diminutive polyps found in the cohort.

References

1) Rex, Douglas K. It’s not lack of evidence holding back resect and discard. Gastrointestinal Endoscopy, Volume 96, Issue 6, 1033 - 1035.
2) Willems P, Djinbachian R, Ditisheim S, Orkut S, Pohl H, Barkun A, Bouin M, Faulques B, von Renteln D. Uptake and barriers for implementation of the resect and discard strategy: an international survey. Endosc Int Open. 2020 May;8(5):E684-E692.

Disclosure

Dr Rex is a consultant for Olympus Corporation, Boston Scientific, Aries Pharmaceutical, Braintree Laboratories, Lumendi Ltd., Norgine, Endokey, GI Supply,
Medtronic, and Acacia Pharmaceuticals; the recipient of research support from EndoAid, Olympus Corporation, Medivators, Erbe USA Inc, and Braintree Laboratories; and a shareholder in Satisfai Health. Dr Pohl has received research funding from Steris, Cosmo, and is an advisory board member of InterVenn. Dr von Renteln has received research funding from ERBE Elektromedizin GmbH, Ventage, Pendopharm, Fujifilm, and Pentax and has received consultant or speaker fees from Boston Scientific Inc, ERBE Elektromedizin GmbH, and Pendopharm. The remaining authors disclose no conflicts.

Introduction

Endoscopic removal of colorectal polyps is a cornerstone of colorectal cancer prevention.¹ Optimal techniques for removing small polyps (≤10mm) remain scarce,^2–4 with cold snare polypectomy (CSP), hot snare polypectomy (HSP), and cold forceps (CF) being the main options.^1–4

Aims & Methods

This systematic review and network meta-analysis aims to compare the efficacy of these techniques for removing small colorectal polyps and determine the optimal approach. We searched Web of Science, PubMed, Cochrane CENTRAL, and Scopus from inception until March 2024 for relevant randomized controlled trials and observational studies comparing CSP, HSP, and CF (including sub-techniques) for small polyp removal. Records were screened for eligible studies, and all relevant outcomes were pooled as a risk ratio (RR) with the corresponding 95% confidence intervals (CI) in a network meta-analysis (NMA) model, using R software.

Results

Our findings from 13 studies (2767 patients) showed insignificant differences among HSP versus CSP in terms of complete resection rate (CRR) and incomplete resection rate (IRR) [RR 2.00, (95% CI, 0.53 to 7.51); P = 0.74] and [RR 1.24, (95% CI, 0.20 to 7.85); P = 0.43], respectively. In addition, no significant variance was detected between the CSP and CF in terms of complete histological polyp eradication (CHPE), incomplete histological polyp eradication (IHPE), and visual polyp eradication (VPE) [RR 0.97, (95% CI, 0.87 to 1.08); P = 0.1], [RR 1.36, (95% CI, 0.57 to 3.26); P = 0.9], and [RR 0.75, (95% CI, 0.62 to 0.91); P = 0.07], respectively.

Conclusion

In conclusion, our results revealed no significant difference between any of the techniques in terms of their success rate in completely removing the polyp. These findings suggest that all three methods might be equally effective for removing small polyps. However, we recommend further studies with more participants, and longer follow-up periods might be needed to definitively determine the best approach for all situations. This could include considering factors like specific polyp characteristics or patient preferences.

References

1. Kaltenbach T, Anderson JC, Burke CA, et al. Endoscopic Removal of Colorectal Lesions—Recommendations by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2020;158(4):1095-1129. doi:10.1053/j.gastro.2019.12.018

2. Abuelazm M, Mohamed I, Jaber FS, et al. Cold Versus Hot Snare Polypectomy for Colorectal Polyps: An Updated Systematic Review and Meta-analysis of Randomized Controlled Trials. J Clin Gastroenterol. 2023;57(8). https://journals.lww.com/jcge/fulltext/2023/09000/cold_versus_hot_snare_polypectomy_for_colorectal.4.aspx.

3. Niu C, Bapaye J, Zhang J, et al. Systematic review and meta-analysis of cold snare polypectomy and hot snare polypectomy for colorectal polyps. J Gastroenterol Hepatol. 2023;38(9):1458-1467. doi:https://doi.org/10.1111/jgh.16312

4. CAVASSOLA PRP, MOURA DTH de, HIRSCH BS, LANDIM DL, BERNARDO WM, MOURA EGH de. HOT VERSUS COLD SNARE FOR COLORECTAL POLYPECTOMIES SIZED UP TO 10MM: A SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMIZED CONTROLLED TRIALS. Arq Gastroenterol. 2024;61. doi:10.1590/s0004-2803.246102023-143

Disclosure

There is no any conflict of interest to disclose.

Introduction

Histopathology is the accepted gold standard for classifying colorectal polyps. However, the complex pathway from initial polyp detection and resection to final histological diagnosis involves multiple steps (retrieval, embedding, sectioning, interpretation), each potentially introducing diagnostic errors.

Aims & Methods

We aimed to investigate the diagnostic accuracy of autonomous computer-aided optical polyp diagnosis (CADx) versus histopathology, using expert consensus as the reference standard. In this prospective study, three internationally recognized expert endoscopists independently reviewed colonoscopy images and videos of diminutive (≤5 mm) polyps assessed by autonomous CADx. Unanimous, high-confidence expert agreement was defined as the reference standard (‘ground truth’), assumed superior due to absence of resection or specimen-management related artifacts. The primary outcome was the proportion of specimens with potential incorrect histopathology diagnosis. Secondary outcomes included comparative accuracy, sensitivity, and specificity of autonomous CADx and histopathology against the expert-defined reference standard.

Results

Among 510 patients, experts provided unanimous, high-confidence diagnoses for 226 diminutive (≤5 mm) colorectal polyps, serving as the reference standard. The proportion of potentially incorrect pathology diagnoses was 23% (95% CI: (17.8,29.2)). Autonomous CADx achieved a higher accuracy of 91.2% (95% CI: 86.5–94.4%), compared with pathology at 77.0% (95% CI: 70.8–82.2%; p < 0.001).

Conclusion

These findings highlight that histopathological diagnosis after polyp resection is not infallible and can introduce diagnostic errors in a relevant proportion of cases. CADx diagnosis, obtained during the procedure and unaffected by specimen handling artifacts, may prevent some of these errors, suggesting it could offer superior accuracy for polyp characterization in certain cases.

Disclosure

Daniel von Renteln has received research funding from ERBE Elektromedizin GmbH, Ventage, Pendopharm, Satisfai, Fujifilm, and Pentax, and has received consultant or speaker fees from Boston Scientific Inc., ERBE Elektromedizin GmbH, Medtronic, and Pendopharm. Roupen Djinbachian has received speaker fees from Fujifilm. The remaining authors declare that they have no conflict of interest.