Utility of linked color imaging for endoscopic diagnosis of early gastric cancer

BACKGROUND Linked color imaging(LCI) is a method of endoscopic imaging that emphasizes slight differences in red mucosal color.AIM To evaluate LCI in diagnostic endoscopy of early gastric cancer and to compare LCI and pathological findings.METHODS Endoscopic images were obtained for 39 patients(43 lesions) with early gastric cancer. Three endoscopists evaluated lesion recognition with white light imaging(WLI) and LCI. Color values in Commission Internationale de l'Eclairage(CIE)1976 L*a*b* color space were used to calculate the color difference(ΔE) between cancer lesions and non-cancer areas. After endoscopic submucosal dissection,blood vessel density in the surface layer of the gastric epithelium was evaluated pathologically. The identical region of interest was selected for analyses of endoscopic images(WLI and LCI) and pathological analyses.RESULTS LCI was superior for lesion recognition(P < 0.0001), and ΔE between cancer and non-cancer areas was significantly greater with LCI than WLI(29.4 vs 18.6, P <0.0001). Blood vessel density was significantly higher in cancer lesions(5.96% vs4.15%, P = 0.0004). An a* cut-off of ≥ 24 in CIE 1976 L*a*b* color space identified a cancer lesion using LCI with sensitivity of 76.7%, specificity of 93.0%, and accuracy of 84.9%.CONCLUSION LCI is more effective for recognition of early gastric cancer compared to WLI as a result of improved visualization of changes in redness. Surface blood vessel density was significantly higher in cancer lesions, and this result is consistent with LCI image analysis.

In vivo histological diagnosis for gastric cancer using endocytoscopy

AIM To examine usefulness of virtual biopsy using endocytoscopy by comparing the in vivo endocytoscopic and histopathological images of gastric cancers.METHODS Endocytoscopy was performed in 30 patients with early gastric cancer. Of these, 26 patients showed well differentiated adenocarcinomas, while 4 patients showed poorly differentiated adenocarcinomas(including one signet ring cell carcinoma). Cancerous and non-cancerous areas were observed after double staining with 0.05% crystal violet and 0.1% methylene blue. The endocytoscopic images obtained were evaluated by an expert endoscopist and an expert pathologist without knowledge of patient clinical data, and endocytoscopic and histopathological diagnoses were compared.RESULTS The endocytoscopic images of the cancerous area were assessed as evaluable in 25(83.3%) and 27(90%) patients by endoscopist A and pathologist B, respectively, and those of the non-cancerous area as evaluable in 28(93.3%) and 23(76.7%) patients by the endoscopist and pathologist, respectively. The sensitivity, specificity, and diagnostic accuracy of gastric cancer diagnosis using evaluable endocytoscopic images were 88.0% and 92.9%, and 90.6% by endoscopist A, and 88.9% and 91.3%, and 90.0% by pathologist B, respectively. Evaluation of the diagnostic concordance rate between the endoscopist and the pathologist by inter-observer agreement calculation revealed no significant difference between the two observers. The inter-observer agreement(κ-value) for endocytoscopic diagnosis was 0.745. CONCLUSION Endocytoscopy is useful for the differentiation of cancerous from non-cancerous gastric mucosa, making it a promising tool for virtual biopsy.

Double-balloon endoscopic retrograde cholangiopancreatography for patients who underwent liver operation: A retrospective study

BACKGROUND Double-balloon endoscopic retrograde cholangiography (DB-ERC) is widely performed for biliary diseases after reconstruction in gastrointestinal surgery,but there are few reports on DB-ERC after hepatectomy or living donor liver transplantation (LDLT).AIM To examine the success rates and safety of DB-ERC after hepatectomy or LDLT METHODS The study was performed retrospectively in 26 patients (45 procedures) who underwent hepatectomy or LDLT (liver operation:LO group) and 40 control patients (59 procedures) who underwent pancreatoduodenectomy (control group).The technical success (endoscope reaching the choledochojejunostomy site),diagnostic success (performance of cholangiography),therapeutic success(completed interventions) and overall success rates,insertion and procedure(completion of DB-ERC) time,and adverse events were compared between these groups.RESULTS There were no significant differences between LO and control groups in the technical [93.3%(42/45) vs 96.6%(57/59),P=0.439],diagnostic [83.3%(35/42) vs83.6%(46/55),P=0.968],therapeutic [97.0%(32/33) vs 97.7%(43/44),P=0.836],and overall [75.6%(34/45) vs 79.7%(47/59),P=0.617] success rates.The median insertion time (22 vs 14 min,P <0.001) and procedure time (43.5 vs 30 min,P=0.033) were significantly longer in the LO group.The incidence of adverse events showed no significant difference [11.1%(5/45) vs 6.8%(4/59),P=0.670].CONCLUSION DB-ERC after liver operation is safe and useful but longer time is required,so should be performed with particular care.

Endoscopic ultrasound-guided fine needle aspiration in the differentiation of type 1 and type 2 autoimmune pancreatitis

AIM:To investigate the usefulness of endoscopic ultrasound-guided fine needle aspiration(EUS-FNA) in the differentiation of autoimmune pancreatitis(AIP).METHODS:We retrospectively reviewed 47 of 56 AIP patients who underwent EUS-FNA and met the Asian diagnostic criteria.On 47 EUS-FNA specimens,we evaluated the presence of adequate material and characteristic features of lymphoplasmacytic sclerosing pancreatitis(LPSP) and idiopathic duct-centric pancreatitis(IDCP) mentioned in the International Consensus Diagnostic Criteria and examined if these findings make a contribution to the differential diagnosis of type 1 and type 2 AIP.A disposable 22-gauge needle was used for EUS-FNA.RESULTS:Adequate specimens including pancreatic tissue for differentiating AIP from cancer were obtained from 43 of 47 patients who underwent EUSFNA.EUS-FNA was performed from the pancreatic head in 21 cases,which is known to be technically difficult when performed by core biopsy;there was no significant difference in the results compared with pancreatic body-tail.Nine of 47 patients met level 1 findings of LPSP and 5 patients met level 2 findings of LPSP.No one met level 1 findings of IDCP,but 3 patients met level 2 findings of IDCP.Of 10 seronegative cases,2 cases were diagnosed with "definitive type 1 AIP",and 3 cases were diagnosed with "probable type 2 AIP" when considering both the level 2 histological findings and response to steroids.CONCLUSION:EUS-FNA is useful in the differentiation of type 1 and type 2 AIP,particularly in seronegative cases.

Clinical oncology for pancreatic and biliary cancers:Advances and current limitations

In the early 2000s,the main stream of endoscopic ultrasonography(EUS)changed from a mechanical scanning method to electronic radial or linear scanning methods.Subsequently,useful applications in trans-abdominal ultrasonography came within reach of EUS.In particular,contrast-enhanced EUS(CE-EUS)and EUS-elastography became cutting-edge diagnostic modalities for pancreatic disorders.Each type of pancreatic disorder has characteristic hemodynamics.CE-EUS uses color Doppler flow imaging and harmonic imaging to classify pancreatic lesions.EUS-elastography can assess tissue hardness by measuring its elasticity.This parameter appears to correlate with the malignant potential of the lesions.Tissue elasticity studies can provide information on both its pattern and distribution.The former is the conventional method of morphological diagnosis,but it is restricted to observations made in a region of interest(ROI).The latter is an unbiased analysis that can be performed by image analysis software and is theoretically constant,regardless of the ROI.Though EUSfine needle aspiration(FNA)is also a very useful diagnostic tool,there are several limitations.Diagnostic EUS-FNA of pancreatic cystic lesions has marginal utility mainly due to low sensitivity.Therefore,in particular,endoscopists should keep this limitation in mind.

Diagnostic performance of endoscopic classifications for neoplastic lesions in patients with ulcerative colitis:A retrospective casecontrol study

BACKGROUND It is unclear whether the Japan Narrow-Band Imaging Expert Team(JNET)classification and pit pattern classification are applicable for diagnosing neoplastic lesions in patients with ulcerative colitis(UC).AIM To clarify the diagnostic performance of these classifications for neoplastic lesions in patients with UC.METHODS This study was conducted as a single-center,retrospective case-control study.Twenty-one lesions in 19 patients with UC-associated neoplasms(UCAN)and 23 lesions in 22 UC patients with sporadic neoplasms(SN),evaluated by magnifying image-enhanced endoscopy,were retrospectively and separately assessed by six endoscopists(three experts,three non-experts),using the JNET and pit pattern classifications.The results were compared with the pathological diagnoses to evaluate the diagnostic performance.Inter-and intra-observer agreements were calculated.RESULTS In this study,JNET type 2 A and pit pattern typeⅢ/Ⅳwere used as indicators of low-grade dysplasia,JNET type 2 B and pit pattern typeⅥlow irregularity were used as indicators of highgrade dysplasia to shallow submucosal invasive carcinoma,JNET type 3 and pit pattern typeⅥhigh irregularity/VN were used as indicators of deep submucosal invasive carcinoma.In the UCAN group,JNET type 2 A and pit pattern typeⅢ/Ⅳhad a low positive predictive value(PPV;50.0%and 40.0%,respectively);however,they had a high negative predictive value(NPV;94.7%and 100%,respectively).Conversely,in the SN group,JNET type 2 A and pit pattern typeⅢ/Ⅳhad a high PPV(100%for both)but a low NPV(63.6%and 77.8%,respectively).In both groups,JNET type 3 and pit pattern typeⅥ-high irregularity/VN showed high specificity.The interobserver agreement of JNET classification and pit pattern classification for UCAN among experts were 0.401 and 0.364,in the same manner for SN,0.666 and 0.597,respectively.The intra-observer agreements of JNET classification and pit pattern classification for UCAN among experts were 0.387,0.454,for SN,0.803 and 0.567,respectively.CONCLUSION The accuracy of endoscopic diagnosis using both classifications was lower for UCAN than for SN.Endoscopic diagnosis of UCAN tended to be underestimated compared with the pathological results.

Clinical characteristics of gastrointestinal immune-related adverse events of immune checkpoint inhibitors and their association with survival

BACKGROUND Despite the popularity of immune checkpoint inhibitors(ICIs)in the treatment of advanced cancer,patients often develop gastrointestinal(GI)and non-GI immune-related adverse events(irAEs).The clinical characteristics and survival outcomes of GI-irAEs have not been fully elucidated in previous reports.This necessitates the evaluation of the impact of GI-irAEs on patients receiving ICI treatment.AIM To evaluate the clinical characteristics of GI-irAEs and their impact on survival in patients treated with ICIs.METHODS In this single-center,retrospective,observational study,we reviewed the records of 661 patients who received ICIs for various cancers at Nagoya University Hospital from September 2014 to August 2020.We analyzed the clinical characteristics of patients who received ICI treatment.We also evaluated the correlation between GI-irAE development and prognosis in non-small cell lung cancer(LC)and malignant melanoma(MM).Kaplan-Meier analysis was used to compare the median overall survival(OS).Multivariate Cox proportional hazards models were used to identify prognostic factors.A P value<0.05 was considered statistically significant.RESULTS GI-irAEs occurred in 34 of 605 patients(5.6%)treated with an anti-programmed cell death-1/programmed death-ligand 1(anti-PD-1/PD-L1)antibody alone and in nine of 56 patients(16.1%)treated with an anti-cytotoxic T-lymphocyte antigen 4(CTLA-4)antibody alone or a combination of anti-PD-1 and anti-CTLA-4 antibodies.The cumulative incidence and median daily diarrhea frequency were significantly higher in patients receiving anti-CTLA-4 antibodies(P<0.05).In 130 patients with MM,OS was significantly prolonged in the group that continued ICI treatment despite the development of GI-irAEs compared to the group that did not experience GI-irAEs(P=0.035).In contrast,in 209 patients with non-small cell LC,there was no significant difference in OS between the groups.The multivariate analyses showed that a performance status of 2-3(hazard ratio:2.406;95%confidence interval:1.125–5.147;P=0.024)was an independent predictive factor for OS in patients with MM.CONCLUSION Patients receiving anti-CTLA-4 antibodies develop GI-irAEs more frequently and with higher severity than those receiving anti-PD-1/PD-L1 antibodies.Continuing ICI treatment in patients with MM with GI-irAEs have better OS.

Accuracy of carbon dioxide insufflation for endoscopic retrograde cholangiopancreatography using double-balloon endoscopy

BACKGROUND Retrograde cholangiopancreatography using double-balloon endoscopic retrograde cholangiography(DBERC)is a valuable technique to treat biliary stone and jejunobiliary anastomotic stenosis in patients with altered gastrointestinal anatomy.The accurate selection of the route at the anastomosis branch is one of the most important factors in reaching the target in a timely manner.AIM To determine the accuracy of carbon dioxide insufflation enterography(CDE)at the branch for selecting the correct route during DBERC.METHODS We enrolled 52 consecutive patients scheduled for DBERC at our institution from June 2015 to November 2017.Route selection via two methods(visual observation and CDE)was performed in each patient.We determined the correct rate of route selection using CDE.RESULTS Thirty-three patients had a jejunojejunal anastomosis and 19 patients had a gastrojejunal anastomosis.The therapeutic target region was reached in 50 patients.The mean procedure times from the teeth to the target(total insertion time),from the teeth to the branch,and from the branch to the target,and the mean total examination time were 15.2,5.0,8.2,and 60.3 min,respectively.The rate of correct route selection using visual observation and CDE were 36/52(69.2%)and 48/52(92.3%),respectively(P=0.002).The rate of correct route selection using CDE in patients with a jejunojejunal anastomosis was 29/33(87.8%),and the rate in patients with a gastrojejunal anastomosis was 19/19(100%).CONCLUSION CDE is helpful in selecting the route at the branch in the anastomosis for more timely access to the target in patients with altered gastrointestinal anatomy undergoing DBERC.

Real-world local recurrence rate after cold polypectomy in colorectal polyps less than 10 mm using propensity score matching

BACKGROUND Cold polypectomy(CP)is a simple and safe procedure for polyps less than 10 mm in size;however,there is concern about local recurrence following CP because of unidentified margins of excised specimens and the lack of tumor suppression effect by coagulation.Some clinical trials have evaluated local persistent recurrence;their results suggest that a higher rate of local recurrence has not been documented so far.There were few reports that observed the course over long periods of time after CP in clinical practice.AIM To evaluate the presence of local recurrence following CP and hot polypectomy(HP)using propensity score matching.METHODS We analyzed 275 patients who underwent polypectomy for non-pedunculated colorectal polyps less than 10 mm(959 Lesions)between October 2016 and 2017 and underwent follow-up endoscopy subsequently.We divided them into the CP group(706 Lesions),wherein CP was performed,and the HP group(253 Lesions),wherein HP was performed.Using propensity score matching,we extracted 215 Lesions in each group and evaluated the local recurrence and content of CP in the real clinic and adverse events using medical records.RESULTS After propensity score matching,there were no significant differences in the patients’and their endoscopic background(age,use of antithrombotics,indications,size,morphology,location of polyps,and polypectomy device)between the groups.The mean duration between colorectal polypectomy and the next follow-up colonoscopy was 17.5±7.1(range,6-39)mo in the CP group and 15.7±6.0(range,6-35)mo in the HP group,which was significantly longer in the CP group(P=0.005).The local recurrence rate was 0.93%in the CP group and 0.93%in the HP group,without a significant difference(P=0.688).Additionally,no differences were observed in the macroscopic en bloc resection rate,histopathological complete resection rate,and pathological results between the groups.Adverse events did not occur in either group.CONCLUSION Local recurrence after CP was equivalent to that following HP in clinical practice.CP is useful and safe in the treatment of non-pedunculated polyps of less than 10 mm.