Introduction

Magnifying endoscopy (ME) enables clear visualization of microvascular (MV) architecture and microsurface structure [1] [2] and allows real-time visualization of red blood cell flow within subepithelial microvessels. Mean MV blood flow velocity is significantly lower in early gastric cancer than in non-neoplastic lesions [3]. However, MV blood flow velocity in the colorectum has not been investigated and it is unclear whether it is useful for the qualitative diagnosis of colorectal polyps in clinical practice.

Aims & Methods

We aimed to calculate the blood flow velocity in colorectal polyps and the surrounding mucosa, and evaluate its usefulness for the differential diagnosis of colorectal polyps. We retrospectively reviewed videos of colorectal polyps that were endoscopically resected at our hospital between March 2019 and January 2023. All procedures were carried out with a high-resolution optical magnifying endoscope (EC-L600ZP7; Fujifilm Corporation, Tokyo, Japan) and endoscope video system (LASEREO; Fujifilm Corporation). The blood flow velocities of each lesion and surrounding mucosa were carefully evaluated using magnifying blue laser imaging (M-BLI) prior to endoscopic resection. All M-BLI video images were split into 30 fps, and mean blood flow velocities were calculated by the mean movement distance of one tagged red blood cell using split images of videos. We compared mean MV blood flow velocities between lesions and the surrounding mucosa. Furthermore, we calculated the MV blood flow imaging ratio (inside lesion/surrounding mucosa) to avoid the influence of individual differences such as blood pressure.

Results

Adenomas				Hyperplastic polyps
	Blood flow velocity (mm/sec)		(A) / (B)		Blood flow velocity (mm/sec)		(C) / (D)
	(A) Lesions	(B) The surrounding mucosa			(C) Lesions	(D) The surrounding mucosa
mean±SD	1.65±0.66	4.12±1.11	0.41±0.16	mean±SD	2.83±1.10	3.13±0.85	0.89±0.25
(range)	（0.46-2.90）	（1.80-6.20）	（0.1-0.82）	(range)	（1.07-4.50）	（2.30-5.07）	（0.46-1.51）

This study included 30 adenomas (ADs) from 20 patients and 20 hyperplastic polyps (HPs) from 13 patients. No significant differences in age or sex were found between lesion groups. The mean size for ADs and HPs were 4.8 ± 3.1 mm and 3.6 ± 1.8 mm, respectively. The macroscopic type of ADs and HPs were 1 and 0 of 0-Isp, 20 and 13 of 0-Is, and 9 and 7 of 0-IIa, respectively. The mean MV blood flow velocity was significantly lower in ADs (1.65 ± 0.66 mm/sec; range 0.46–2.90) than HPs (2.83 ± 1.10 mm/sec; range 1.07–4.50) or the surrounding mucosa (4.12 ± 1.11 mm/sec; range 1.80–6.20; p < 0.001, respectively). The ratio of the blood flow velocity of lesions compared to the surrounding mucosa was significantly lower in ADs (0.41 ± 0.16; range 0.10–0.82) than HPs (0.89 ± 0.25; range 0.46 – 1.51; p < 0.001).
In summary, MV blood flow velocity was significantly lower in ADs than HPs and the surrounding non-neoplastic mucosa, suggesting blood flow in ADs may be congested. A lower subepithelial MV blood flow rate in ADs compared with non-neoplastic lesions may be due to a difference in caliber and tortuosity of microvessels.

Conclusion

Our results suggest using MV blood flow velocity and ME as a novel dynamic diagnosis for the differential diagnosis of ADs and HPs. However, since this was a single-center retrospective study with a small sample size, further investigation is needed to validate our results and confirm their clinical usefulness.

References

1. Gono, K., et al., J Biomed Opt, 2004. 9(3): p. 568-77.
2. Yoshida, N., et al., J Gastroenterol, 2014. 49(1): p. 73-80.
3. Ueyama, H., et al., J Gastroenterol Hepatol, 2021. 36(7): p. 1927-1934.

Introduction

Sessile serrated lesion (SSL), is a precursor lesion in the serrated neoplasia pathway [1]. These lesions are considered a major contributor to the failure of colonoscopy to prevent colorectal cancers (known as “interval cancer” or “post-colonoscopy colorectal cancer”) [2]. Therefore, improved awareness of the clinicopathological and endoscopic characteristics of SSL and their dysplastic components is important.

Aims & Methods

This study aimed to elucidate the clinicopathological and endoscopic features of SSLs with and without dysplasia or carcinoma. We reviewed the data of all colorectal lesions that were pathologically diagnosed as SSLs at Juntendo University Hospital, Tokyo, Japan, between 2011 and 2022. During this period, all suspected SSLs were resected endoscopically or surgically. The histological diagnosis of SSLs was based on the World Health Organization Classification of Tumours of the Digestive System 2019 [3]. We analysed the clinicopathological features of all the patients, including age, sex, tumour location and size, and conventional endoscopic findings.

Results

Table 1.	Clinicopathological and endoscopic characteristics of colorectal lesions studied.
Variable [Lesions / Patients]	ND [1972 (92.5%) / 1276]	LGD [101 (4.7%) / 94]	HGD [39 (1.8%) / 38]	SIC [20 (0.9%) / 20]
Age (years)	62.8 ± 12.1 (23 - 91)	64.8 ± 10.0 (35 - 85)	71.6 ± 8.9 (51 - 86)	72.2 ± 9.7 (47 - 90)
Sex: Male / Female	667 (52.3%) / 609 (47.7%)	41 (43.6%) / 53 (56.4%)	14 (36.8%) / 24 (63.2%)	7 (35.0%) / 13 (65.0%)
Location: Proximal / Distal	1637 (83.0%) / 335 (17.0%)	81 (80.2%) / 20 (19.8%)	33 (84.6%) / 6 (15.4%)	18 (90.0%) / 2 (10.0%)
Size of tumour (mm)	10.8 ± 7.6 (2 - 65)	15.0 ± 9.0 (5 - 42)	14.2 ± 8.4 (6 - 43)	20.2 ± 12.7 (8 - 65)
(Semi)pedunculated morphology	51 (2.6%)	14 (13.9%)	10 (25.6%)	5 (25.0%)
Reddishness	77 (3.9%)	40 (39.6%)	21 (53.8%)	16 (80.0%)
Double elevation	70 (3.5%)	61 (60.4%)	19 (48.7%)	10 (50.0%)
Central depression	44 (2.2%)	6 (5.9%)	2 (5.1%)	6 (30.0%)

The clinicopathological and endoscopic characteristics of the lesions are summarised in Table 1. Out of 2132 SSLs (1368 patients), 1972 (92.5%) had no dysplasia (ND), 101 (4.7%) had low-grade dysplasia (LGD), 39 (1.8%) had high-grade dysplasia (HGD), and 20 (0.9%) had submucosal invasive carcinoma (SIC). Older age is more frequently associated with SSLs and dysplasia/carcinoma. The most frequent location of tumours was the proximal colon. A stepwise increase in the size of the SSL series was identified, along with dysplastic progression from ND to dysplasia to invasive carcinoma. Similarly, larger lesions were associated with higher rates of dysplasia or cancer (≥ 5 mm, 1.2%; 6 - 10 mm, 6.5%; 11-15 mm; 9.5%, 16-20 mm, 12.9%; ≥ 21 mm, 17.3%). However, 66 of the 160 (41.3%) SSLs with dysplasia/carcinoma were ≤ 10 mm in size. Macroscopically, (semi)pedunculated morphology, reddishness, double elevation, and central depression were more frequently observed in SSLs with dysplasia/carcinoma than in those without.

Conclusion

Our findings suggest that SSLs with dysplasia/carcinoma may be more frequently associated with older age, the proximal colon, and larger lesions. However, dysplasia/cancer could coexist in SSLs even if the size was ≤ 10 mm. Additionally, in an SSL series, endoscopic characteristics, including (semi)pedunculated morphology, reddishness, double elevation, and central depression, might be useful for the accurate diagnosis of advanced histology within an SSL. These results may may contribute to improvement in the recognition and complete resection of SSLs with dysplasia or invasive carcinoma, thereby reducing the rates of colorectal cancer.

References

1. O'Brien MJ, Yang S, Mack C, et al. Comparison of microsatellite instability, CpG island methylation phenotype, BRAF and KRAS status in serrated polyps and traditional adenomas indicates separate pathways to distinct colorectal carcinoma end points. Am J Surg Pathol. 2006; 30: 1491–1501.
2. Sawhney MS, Farrar WD, Gudiseva S, et al. Microsatellite instability in interval colon cancers. Gastroenterology. 2006; 131: 1700–1705.
3. Pai RK, Mäkinen MJ, Rosty C. Colorectal serrated lesions and polyps. In: Nagtegaal ID, Arends MJ, Odze RD, Lam AK (eds). WHO Classification of Tumours of the Digestive System, 5^th edn. Lyon: IARC Press, 2019; 163–169.

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

Computer-aided detection (CADe) system increases the efficiency of adenoma detection during colonoscopy, which is expected to reduce the incidence of colorectal cancer as well as cancer treatment-associated medical costs. However, most lesions detected using CADe have been reported to be diminutive adenomas that may not affect patient prognosis. Additionally, CADe may impose an immediate economic burden because the system needs to be purchased. Consequently, the use of CADe for all colonoscopy procedures seems impractical. This study aimed to evaluate the usefulness of CADe in patients undergoing regular surveillance colonoscopy (SCS), to identify the characteristics of endoscopists and patients who may benefit significantly from CADe.

Aims & Methods

Patients who underwent regular SCS with CADe at Hiroshima University Hospital from January to March 2023 and had undergone colonoscopy at least twice in the previous three years using a conventional detection method were enrolled. Forty-eight endoscopists who had collectively performed ≥800 colonoscopies performed the examinations. Endoscopic resection was performed for lesions ≥6 mm in size, flat and depressed neoplastic lesions ≤5 mm in size, and lesions with suspected high-grade dysplasia or T1a carcinoma, according to Japanese guidelines. Diminutive polypoid adenomas ≤5 mm in size were followed up without resection. Lesions pathologically identified as adenomas >6 mm or carcinomas were defined as index lesions (ILs). Lesions pathologically identified as adenomas ≥10 mm in size, tubulovillous adenomas, and high-grade dysplasia were defined as advanced adenomas (AAs). The clinicopathological findings of the lesions detected by CADe were evaluated, and the outcomes were compared between the semi-clean colon (diminutive polypoid adenomas ≤5 mm in size followed up without resection) and clean colon (no adenomatous polyps) groups.

Results

Overall, 78 patients were included. CADe identified 46 adenomas that were not detected by previous colonoscopy in 28 patients, including three ILs but no AAs. The mean withdrawal time was 824 ± 353 s, and the mean tumor diameter was 3.3 mm (range, 2–8 mm). The most common gross type was 0-Is (70%), followed by 0-Isp (17%) and 0-IIa (13%). Most tumors were located in the ascending and sigmoid colons (28%), followed by the transverse colon (26%), cecum (7%), descending colon (7%), and rectum (4%). The ILs were 0-Isp Isp of 6 mm diameter in the ascending colon, 0-Is of 7 mm diameter in the transverse colon, and 0-Isp Isp of 6 mm diameter in the descending colon, all of which were adenomas with lesions on the folds. Overall, 34.1% and 38.2% of the patients in the semi-clean and clean colon groups, respectively, had newly detected adenomas. No new neoplastic lesions were detected using CADe in patients without a history of endoscopic resection. When comparing the clinical backgrounds of patients with and without new ILs detected in CADe SCS, a significant difference was found in the IL detection rate at the previous SCS between the groups (67% vs. 12%, p = 0.0319).

Conclusion

CADe may help detect adenoma in SCS for patients with semi-clean colons and those with clean colons and a history of endoscopic resection. Its effectiveness is considered more for patients with ILs at the previous SCS.

Introduction

Colonoscopy is the gold standard investigation in the lower gastrointestinal tract. However, 75% of patients can experience pain or discomfort with moderate sedation. The application of robotic technology promises to advance and overcome difficulties faced including better utilisation of rooms for advanced procedures and to achieve a complete colonoscopy in patients where pain and technical challenges inhibit progression.

Aims & Methods

This pilot study, the first at a UK NHS Hospital between January 2023 to April 2025 with an expert endoscopist performing the robotic colonoscopy with the Endotics system. This is a disposable soft robot which employs expand and contract movement to self-propel along the bowel. Patients with failed previous standard colonoscopy along with index diagnostic procedures deemed potentially difficult were recruited. Procedures were performed outside the endoscopy unit similar to an outpatient clinical room.

Results

112 patients were recruited (50M:62F), mean-age 56.3 years over 27 months. The commonest indications for robotic colonoscopy were rectal bleeding (36.9%), failed standard colonoscopy (22.6%) and change in bowel habit (17.2%). 23 patients had failed previous standard colonoscopy with 16 patients achieving completion with subsequent robotic colonoscopy (70% improvement). Average caecal intubation time 36.63 minutes with average total procedure time 48.74 minutes.

Conclusion

Robotic colonoscopy provides a safe and effective method in improving comfort and completion-rates, including previously failed colonoscopy. Direct visualisation, biopsy and polypectomy is still possible with robotic colonoscopy. This study has demonstrated a viable alternative to conventional colonoscopy. With no sedation it allows procedures to be conducted outside the traditional endoscopy unit such as outpatients. The study highlights a learning curve to reduce caecal intubation time. The study is expanding with further endoscopists being trained in robotic endoscopy with a view to expand the service available to patients.

Introduction

Full-thickness endoscopic resection (FTRD) using the Colonic FTRD Ovesco system represents a significant advancement in the management of complex colorectal lesions (1). This technique is particularly valuable for treating adenomatous recurrences occurring on post-resection scars smaller than 20 mm, especially in cases of failed submucosal lifting, offering an alternative to submucosal dissection (2).

Aims & Methods

This French retrospective monocentric study reports on the use of the colonic FTRD system, performed by two experienced operators, including the first clinician to perform this procedure in France. The study collected data on patient demographics, indications, resection sites, technical and clinical success rates, R0 resection rates, and procedure-related complications.

Results

Between 2016 and 2024, 87 patients (48 women and 39 men) with a median age of 66 years [32–87] were included. The primary indication was adenomatous recurrence after endoscopic mucosal resection (EMR) (69% of cases,n=60). Other indications included appendicular lesions in patient who had undergone appendicectomy (8%, n=7), suspected superficial submucosal carcinoma (7%, n=6), submucosal lesions (SML) (6%, n=5), and diverticular adenomatous lesions (3%, n=3). Most lesions (67%, n=58) were located in the right colon with a median estimated size before resection 18 mm [10–50 mm].
The overall technical success rate—defined as the complete execution of the resection—was 89%. There were 10 failures : failure to reach the site of recurrence (n=2), failure to achieve complete sectioning (n=5), and intraoperative complications (n=3), including three perforations. Two occurred while advancing through sigmoid diverticulosis , and one resulted from current diffusion into the colonic wall.
The R0 histological resection rate was 89% (n=71). 70% were adenomatous (low-grade dysplasia: n=36, high-grade dysplasia: n=13, serrated lesions without dysplasia: n=8). 8 cases (10%) were adenocarcinomas. Five cases involved submucosal tumors, including two neuroendocrine tumors. In 15% of cases (n=12), the resected specimen consisted solely of fibrotic scar tissue.
Early complications included 3 perforations, one of which was managed endoscopically, while the other two required immediate surgical intervention. Delayed complications were observed in 6% of cases, consisting of three episodes of post-procedural bleeding and two ileal perforations. The latter occurred on the suture line of the ileal reservoir in patients with a history of coloprotectomy and ileoanal anastomosis with a J-pouch for familial adenomatous polyposis.
This study confirms the efficacy of using the FTRD Ovesco system for lesions < 20 mm. The primary indications include post EMR recurrences with failed lifting, intra-appendicular adenomas, and submucosal tumors of the colon. Compared to submucosal dissection this technique offers a practical alternative, especially considering its lower morbidity, even with traction-assisted dissection. However, caution is advised in two specific situations, where alternative techniques may be preferable: severe diverticulosis with pseudo-stenosis and lesions developing on surgical anastomoses with a J-pouch reservoir.

Conclusion

The FTRD Ovesco system demonstrates excellent efficacy and safety for complex colonic lesions, including post-resection recurrences, submucosal tumors, and challenging locations such as appendicular sites. This technique represents an essential tool in expert endoscopic centers, offering a valuable alternative to other resection techniques with higher associated morbidity.

References

1. Dolan RD, et al. Endoscopic full-thickness resection of colorectal lesions: a systematic review and meta-analysis, Gastrointest 2022.
2. Yzet et al , Use of endoscopic submucosal dissection or full-thickness resection device to treat residual colorectal neoplasia after endoscopic resection: a multicenter historical cohort study , endoscopy 2023