Enhancing polyp detection: technological advances in colonoscopy imaging.

The detection and removal of polyps at colonoscopy is core to the current colorectal cancer (CRC) prevention strategy. However, colonoscopy is flawed with a well described miss rate and variability in detection rates associated with incomplete protection from CRC. Consequently, there is significant interest in techniques and technologies which increase polyp detection with the aim to remedy colonoscopy's ills. Technologic advances in colonoscope imaging are numerous and include; increased definition of imaging, widening field of view, virtual technologies to supplant conventional chromocolonoscopy (CC) and now computer assisted detection. However, despite nearly two decades of technologic advances, data on gains in detection from individual technologies have been modest at best and heterogenous and conflicted as a rule. This state of detection technology science is exacerbated by use of relatively blunt metrics of improvement without consensus, the myopic search for gains over single generations of technology improvement and an unhealthy focus on adenomatous lesions. Yet there remains cause for optimism as detection gains from new technology, while small, may still improve CRC prevention. The technologies are also readily available in current generation colonoscopes and have roles beyond simply detection such as lesion characterization, further improving their worth. Coupled with the imminent expansion of computer assisted detection the detection future from colonoscope imaging advances looks bright. This review aims to cover the major imaging advances and evidence for improvement in polyp detection.

Piecemeal cold snare polypectomy versus conventional endoscopic mucosal resection for large sessile serrated lesions: a retrospective comparison across two successive periods.

OBJECTIVE: Large (≥20 mm) sessile serrated lesions (L-SSL) are premalignant lesions that require endoscopic removal. Endoscopic mucosal resection (EMR) is the existing standard of care but carries some risk of adverse events including clinically significant post-EMR bleeding and deep mural injury (DMI). The respective risk-effectiveness ratio of piecemeal cold snare polypectomy (p-CSP) in L-SSL management is not fully known. DESIGN: Consecutive patients referred for L-SSL management were treated by p-CSP from April 2016 to January 2020 or by conventional EMR in the preceding period between July 2008 and March 2016 at four Australian tertiary centres. Surveillance colonoscopies were conducted at 6 months (SC1) and 18 months (SC2). Outcomes on technical success, adverse events and recurrence were documented prospectively and then compared retrospectively between the subsequent time periods. RESULTS: A total of 562 L-SSL in 474 patients were evaluated of which 156 L-SSL in 121 patients were treated by p-CSP and 406 L-SSL in 353 patients by EMR. Technical success was equal in both periods (100.0% (n=156) vs 99.0% (n=402)). No adverse events occurred in p-CSP, whereas delayed bleeding and DMI were encountered in 5.1% (n=18) and 3.4% (n=12) of L-SSL treated by EMR, respectively. Recurrence rates following p-CSP were similar to EMR at 4.3% (n=4) versus 4.6% (n=14) and 2.0% (n=1) versus 1.2% (n=3) for surveillance colonoscopy (SC)1 and SC2, respectively. CONCLUSIONS: In a historical comparison on the endoscopic management of L-SSL, p-CSP is technically equally efficacious to EMR but virtually eliminates the risk of delayed bleeding and perforation. p-CSP should therefore be considered as the new standard of care for L-SSL treatment.

The Cold Revolution: How Far Can It Go?

Cold resection for small colonic polyps, and larger lesions, is being rapidly and widely adopted. Driven by an impressive safety and cost profile compared with conventional polypectomy, these advantages are offset by the limitations of smaller and shallower resection, and absent thermal effects that may permit persistence of residual neoplasia. To overcome this, optimal cold snare technique requires inclusion of a margin of normal mucosa and a piecemeal resection technique for larger polyps. This article examines the fundamentals of cold snare resection and evidence for its application, theorizes on limits to its application, and identifies areas for further research.

Cold EMR of large sessile serrated polyps at colonoscopy (with video).

BACKGROUND AND AIMS: The optimal technique for the resection of sessile serrated polyps (SSPs) is unknown, with established limitations and risks with conventional polypectomy. Although cold snare polypectomy is safe, the efficacy of piecemeal resection for large lesions is untested. In this study we evaluate the safety and efficacy of cold EMR for large SSPs. METHODS: Patients presenting for elective colonoscopy at an academic endoscopy center with 1 or more SSPs ≥10 mm in size were enrolled, excluding those on anticoagulant or antiplatelet therapy other than aspirin. Lesions were resected with a cold EMR technique comprising submucosal injection of succinylated gelatin and dilute methylene blue before piecemeal cold snare resection of all visible polyp with a margin of normal tissue. Outcomes were the presence of residual serrated neoplasia in biopsy specimens from the defect margin and findings on surveillance colonoscopy. RESULTS: Cold EMR was performed on 163 SSPs during 105 procedures in 99 patients (97% women; median age, 57 years). The mean size was 17.5 mm: 61 SSPs were ≥20 mm and 13 SSPs ≥30 mm, and 97.5% were in the proximal colon. Cytologic dysplasia was present in 2 (1.2%). Margin biopsy specimens were positive in 2 lesions (1.2%). Surveillance colonoscopy for 82% of lesions (median, 5 months) showed residual serrated tissue in 1, treated with cold snare, but no evidence of recurrence in the remainder. Minor adverse events were seen in 3 patients; no delayed bleeding was observed. CONCLUSIONS: Cold EMR is a safe and effective method for the removal of large SSPs.

Endoscopic mucosal resection for large serrated lesions in comparison with adenomas: a prospective multicentre study of 2000 lesions.

OBJECTIVE: Endoscopic mucosal resection (EMR) is effective for large laterally spreading flat and sessile lesions (LSLs). Sessile serrated adenomas/polyps (SSA/Ps) are linked to the relative failure of colonoscopy to prevent proximal colorectal cancer. We aimed to examine the technical success, adverse events and recurrence following EMR for large SSA/Ps in comparison with large conventional adenomas. DESIGN: Over 74 months till August 2014, prospective multicentre data of LSLs ≥20 mm were analysed. A standardised dye-based conventional EMR technique followed by scheduled surveillance colonoscopy was used. RESULTS: From a total of 2000 lesions, 323 SSA/Ps in 246 patients and 1527 adenomas in 1425 patients were included for analysis. Technical success for EMR was superior in SSA/Ps compared with adenomas (99.1% vs 94.5%, p<0.001). Significant bleeding and perforation were similar in both cohorts. The cumulative recurrence rates for adenomas after 6, 12, 18 and 24 months were 16.1%, 20.4%, 23.4% and 28.4%, respectively. For SSA/Ps, they were 6.3% at 6 months and 7.0% from 12 months onwards (p<0.001). Following multivariable adjustment, the HR of recurrence for adenomas versus SSA/Ps was 1.7 (95% CI 0.9 to 3.0, p=0.097). Subgroup analysis by lesion size revealed an eightfold increased risk of recurrence for 20-25 mm adenomas versus SSA/Ps, but no significantly different risk between lesion types in larger lesion groups. CONCLUSION: Recurrence after EMR of 20-25 mm LSLs is significantly less frequent in SSA/Ps compared with adenomatous lesions. SSA/Ps can be more effectively removed than adenomatous LSLs with equivalent safety. Ensuring complete initial resection is imperative for avoiding recurrence. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT01368289.

A standardized imaging protocol is accurate in detecting recurrence after EMR.

BACKGROUND AND AIMS: EMR of large laterally spreading lesions (LSL) in the colon is a safe and effective alternative to surgery. Post-EMR scar assessment currently involves taking biopsy specimens of the scar to detect residual or recurrent adenoma (RRA). The accuracy of endoscopic imaging of the post-EMR scar is unknown. We aimed to determine the accuracy of a standardized imaging protocol in post-EMR scar assessment. METHODS: Prospective, single-center data from the Australian Colonic EMR study were analyzed. Consecutive patients undergoing first surveillance colonoscopy (SC1) after EMR of a large LSL were eligible. All scars were sequentially examined with high-definition white light (HD-WL) and narrow-band imaging (NBI) in a standardized fashion and then biopsies were performed. Endoscopic recurrence (recurrence at the post-EMR scar detected by systematic endoscopic assessment) was compared with the histologic findings. RESULTS: One hundred eighty-three post-EMR scars were included. Thirty of 183 (16.4%) were confirmed to have RRA histologically at SC1. Thirty-seven of 183 (20.2%) post-EMR scars demonstrated RRA endoscopically. The sensitivity and specificity of endoscopic RRA detection were 93.3% (95% confidence interval [CI], 77.9%-99.2%) and 94.1% (95% CI, 89.1%-97.3%), respectively. The positive predictive value was 75.7% (95% CI, 58.8%-88.2%) and the negative predictive value was 98.6% (95% CI, 95.1%-99.8%). The diagnostic accuracy was 94.0%. Sensitivity was higher for the combination of HD-WL and NBI as opposed to HD-WL alone (93.3% vs 66.7%). The specificity was high for both HD-WL and HD-WL + NBI (96.1% and 94.1%, respectively). Flat morphology of RRA was better seen with NBI (P = .002). CONCLUSIONS: Endoscopic detection of RRA in the post-EMR scar is highly accurate using a standardized imaging protocol with HD-WL and NBI. This allows real-time, accurate detection of recurrence and its concurrent treatment, and raises the possibility that routine biopsy of the post-EMR scar may not be necessary.

Patient acceptance of the optical diagnosis and misdiagnosis of diminutive colorectal polyps.

BACKGROUND AND AIMS: Optical diagnosis allows for real-time endoscopic assessment of colorectal polyp histology and consists of the resect and discard and diagnose and leave paradigms. This survey assessed patient acceptance of optical diagnosis and their responses to a hypothetical doomsday scenario. METHODS: We conducted a 3-month cross-sectional survey of colonoscopy outpatients presenting to an Australian academic endoscopy center. RESULTS: A total of 981 patients completed the survey (76.0% response rate). The 60.8% of patients who supported resect and discard were more likely to be older men who co-supported diagnose and leave. Fewer patients (49.6%) supported diagnose and leave. A family history of missed cancer diagnosis (odds ratio [OR], 0.59; P = .003) was significantly associated with rejection of resect and discard, and a personal or family history of bowel cancer (OR, 0.7; P = .04) was significantly associated with rejection of diagnose and leave. In the hypothetical scenario of a cancerous polyp incorrectly left in situ leading to stage III disease, 208 (21.2%) patients would definitely ask for financial compensation, 584 (59.5%) were unsure, and 189 (19.3%) would definitely not seek compensation. The patient-proposed median value of compensation sought was $760,000 USD ($1,000,000 AUD; $1 AUD = $0.76 USD). Notably, 18.5% would be willing to give optical diagnosis another chance after this error. CONCLUSION: Patient support for optical diagnosis is limited, and those who are not supporters are more likely to seek financial compensation if errors occur.

Endoscopic resection of subtotal or completely circumferential laterally spreading colonic adenomas: technique, caveats, and outcomes.

BACKGROUND AND STUDY AIMS: Endoscopic mucosal resection (EMR) is an established treatment for large (≥ 20 mm) laterally spreading lesions (LSLs). LSLs with complete or subtotal (> 90 %) circumferential extent (C-LSLs) are generally referred for surgery. Data on technique, efficacy, and safety of EMR for these lesions are absent. The aim of this study was to describe the technique and long-term outcomes of EMR for C-LSLs. PATIENTS AND METHODS: Prospective observational study of consecutive patients referred for EMR of LSL at a tertiary care center over 63 months to April 2015. Amongst 979 patients with LSL, 12 patients with C-LSL were seen. RESULTS: All lesions were tubulovillous adenomas with granular 0 - IIa + Is morphology. Median longitudinal extent was 95 mm (range 60 - 160), 58 % were located in the rectum, and 3 lesions (25 %) had complete circumferential involvement. EMR technical success was 100 %. There were no major adverse events. Symptomatic stricturing occurred in 2 cases (17 %) and was treated with endoscopic balloon dilation (median 4 sessions). Median follow up is 13 months. Minor residual adenoma was found in 7 (58 %) at first surveillance colonoscopy and was treated with snare excision. A total of 10 patients have completed a second surveillance colonoscopy with minor residual adenoma found in only 1 case. No patient required surgery or developed cancer in long-term follow-up. CONCLUSIONS: Endoscopic resection of C-LSL is feasible and safe. Minor residual adenoma is common but endoscopically treatable with long-term cure. Symptomatic stricturing amenable to balloon dilation may occur. Empiric surgical referral for C-LSL based on extensive circumferential involvement may be avoided.ClinicalTrials.gov NCT01368289.

Endoscopic resection of advanced and laterally spreading duodenal papillary tumors.

Historically, neoplasia of the duodenal papilla has been managed surgically, which may be associated with substantial morbidity and mortality. In the absence of invasive cancer, even lesions with extensive lateral duodenal wall involvement, or limited intraductal extension may be cured endoscopically with a superior safety profile. Endoscopic papillectomy is associated with greater risks of adverse events such as bleeding than resection elsewhere in the gastrointestinal tract. Additionally site-specific complications such as pancreatitis exist. A structured approach to lesion assessment, adherence to technical aspects of resection, endoscopic management of complications and post-resection surveillance is required. Advances have been made in all facets of endoscopic papillary resection since its introduction in the 1980s; extending the boundaries of endoscopic cure, optimizing outcomes and enhancing patient safety. These will be the focus of the present review.

Feasibility and Safety of Overtubes for PEG-Tube Placement in Patients with Head and Neck Cancer.

Background. Percutaneous endoscopic gastrostomy (PEG) placement using the "pull" technique is commonly utilized for providing nutritional support in head and neck cancer (HNC) patients, but it may be complicated by peristomal metastasis in up to 3% of patients. Overtube-assisted PEG placement might reduce this risk. However, this technique has not been systemically studied for this purpose to date. Methods. Retrospective analysis of consecutive patients with HNC who underwent overtube-assisted PEG placement at Westmead Hospital, Australia, between June 2011 and December 2013. Data were extracted from patients' endoscopy reports and case notes. We present our technique for PEG insertion and discuss the feasibility and safety of this method. Results. In all 53 patients studied, the PEG tubes were successfully placed using 25 cm long flexible overtubes, in 89% prophylactically (before commencing curative chemoradiotherapy), and in 11% reactively (for treatment of tumor related dysphagia or weight loss). During a median follow-up period of 16 months, 3 (5.7%) patients developed peristomal infection and 3 others developed self-limiting peristomal pain. There were no cases of overtube-related adverse events or overt cutaneous metastases observed. Conclusions. Overtube-assisted PEG placement in patients with HNC is a feasible, simple, and safe technique and might be effective for preventing cutaneous metastasis.

Characterization and significance of protrusions in the mucosal defect after cold snare polypectomy.

BACKGROUND: Cold snare polypectomy (CSP) is widely practiced; however, the endoscopic features of the CSP mucosal defect have not been studied. In particular, protrusions within the cold snare defect (CSDPs) may create concern for residual polyp. The frequency and constituents of this phenomenon are unknown. OBJECTIVE: To describe the frequency, predictors, and histologic constituents of CSDPs. DESIGN: Prospective observational study. SETTING: Tertiary-care hospital endoscopy unit. PATIENTS: Eighty-eight consecutive patients undergoing CSP for a polyp ≤ 10 mm in size. INTERVENTION: Inspection of the cold snare mucosal defect with high-definition white light and biopsy sampling of CSDPs for separate histologic assessment, when present. MAIN OUTCOME MEASUREMENT: Frequency and constituents of CSDPs. RESULTS: Two hundred fifty-seven consecutive polyps ≤ 10 mm in size were removed in 88 patients (50 men [57%], mean age 63 years). Polyps were predominately adenomatous (162, 63%), located in the proximal colon (159, 62%) and flat (200, 78%). Mean lesion size was 5.5 mm (range, 2-10 mm). High-grade dysplasia was present in a single polyp for which the defect was bland. CSDPs occurred in 36 polypectomies (14%). CSDPs were associated with polyp size ≥ 6 mm (odds ratio, 3.7; P < .001 multivariable analysis) but not age, sex, lesion, histopathology, morphology, or location. Histopathologic examination of CSDPs revealed submucosa in 34 (94%) and muscularis mucosa in 29 (80%). No residual adenomatous or serrated polyp tissue was detected. LIMITATIONS: Single-center study. Small number of polyps with high-grade dysplasia. CONCLUSION: Protrusions are common within the CSP mucosal defect and are associated with polyp size ≥ 6 mm. CSDPs do not represent vascular structures, do not contain residual polyp, and are not associated with adverse outcomes in short-term follow-up. However, CSDPs represent incomplete mucosal layer resection.

Endoscopic mucosal resection of laterally spreading lesions involving the ileocecal valve: technique, risk factors for failure, and outcomes.

BACKGROUND AND STUDY AIMS: Endoscopic mucosal resection (EMR) of laterally spreading lesions (LSLs) involving the ileocecal valve (ICV) is technically demanding. Conventionally, these lesions are considered too challenging for endoscopic therapy and are primarily managed surgically. The aims of the study were to describe effectiveness, safety, and outcomes following EMR of LSLs at the ICV. PATIENTS AND METHODS: This was a single-center, prospective, observational, cohort study performed at an academic, tertiary referral center. Patients undergoing EMR for LSLs ≥ 20 mm involving the ICV were recruited over a 5-year period. Standard or cap-assisted colonoscopy with inject-and-resect EMR technique was performed with standardized post-EMR management. Procedural success, safety, and outcomes compared with non-ICV LSLs managed during the same period were analyzed. RESULTS: A total of 53 patients with ICV LSLs were referred for EMR (median age 69 years; median lesion size 35.0 mm; 52.8 % females). Six patients went directly to surgery because of an endoscopic diagnosis of malignancy (n = 2) or technical failure of EMR (n = 4). EMR achieved complete adenoma clearance in 44 out of 47 attempted (93.6 %). Surgery was ultimately avoided in 43/53 (81.1 %). Complications included bleeding in 6.4 %. There were no perforations or strictures. Early adenoma recurrence was detected in 7/40 patients (17.5 %), and 1/22 (4.5 %) had late recurrence. All were successfully managed endoscopically. Factors associated with failure of ICV EMR were ileal infiltration and involvement of both ICV lips. CONCLUSIONS: In the majority of cases, LSL involving the ICV can be effectively treated by EMR on an outpatient basis. In specialized centers, complications are infrequent, and  > 80 % of patients ultimately avoid surgery. Trial registered at ClinicalTrials.gov (NCT01368289).

Endosonography-guided drainage of malignant fluid collections using lumen-apposing, fully covered self-expanding metal stents.

Endosonography (EUS)-guided drainage of paragastric fluid collections using fully covered self-expanding metal stents (FCSEMS) is now a well-established procedure. Recently, new and specially designed lumen-apposing, fully-covered metal cystgastrostomy stents have been employed for this indication. In this case series, the use of these new stents for the drainage of malignant fluid collections in three symptomatic patients is described. Cases included a large pancreatic pseudocyst, secondary to underlying acute lymphoblastic leukemia, and two large collections of loculated ascites due to metastatic ovarian and cervical cancer, respectively. Technical success in inserting the new stents was achieved in all three patients, and resulted in symptomatic relief. There were no clinically significant complications directly attributed to the stents. These new lumen-apposing cystgastrostomy stents may provide a viable, minimally invasive, and effective alternative for drainage of malignant fluid collections, either for definitive treatment or for palliation of symptoms.

Advances in colonoscopy.

OPINION STATEMENT: Colonoscopy with polypectomy has been established as the major prevention and detection strategy for colorectal cancer for over a decade. Over this period advances in colonoscopic imaging, polyp detection, prediction of histopathology and polypectomy techniques have all been seen; however, the true magnitude of the limitations of colonoscopy has only recently been widely recognized. The rate and location of missed or interval cancers after complete colonoscopy appears to be influenced by the operator-dependency of colonoscopy and failure of conventional practices to detect and treat adenomatous, and possibly more importantly, non-adenomatous colorectal cancer precursors. Consequently, studies that expand our understanding of these factors and advances that aim to improve colonoscopy, polypectomy, and cancer protection are of critical importance.