Laparoscopic Resection of Transverse Colon Cancer with an Anomaly of the Middle Colic Artery Originating from the Splenic Artery: A Case Report.

Introduction: We encountered a colon cancer case with a very rare anomaly of the middle colic artery (MCA) originating from the splenic artery (SA). Case Presentation: A woman was referred to our hospital for transverse colon cancer. Three-dimensional computed tomography (3D-CT) angiography showed an anomalous MCA originating from the SA rather than from the superior mesenteric artery (SMA) as is typical. Laparoscopic left hemicolectomy with D3 lymph node dissection was performed. The lymph nodes around the SMA were dissected from the caudal view, confirming the absence of a typical MCA. An anomalous SA-originating MCA was identified just below the pancreas, where it was clipped and ligated; subsequently, total mesenteric excision was achieved. Conclusion: As D3 lymph node dissection for transverse colon cancer is technically difficult, 3D-CT angiography is useful for identifying vascular anomalies preoperatively, thereby avoiding intraoperative injury. This is the first case report of laparoscopic colectomy associated with a SA-originating MCA anomaly.

Short-term and long-term outcomes of submucosal dissection for residual or recurrent colorectal tumors after endoscopic resection: Analysis of a multicenter prospective study.

OBJECTIVES: We previously demonstrated that a favorable long-term prognosis indicated that endoscopic submucosal dissection (ESD) could be the standard treatment for large colorectal epithelial neoplasms, but the usefulness of ESD for local residual or recurrent tumors with submucosal fibrosis has not been fully demonstrated. The aim of the present study was to assess the usefulness of ESD for local residual or recurrent colorectal tumors. METHODS: We conducted a nationwide multicenter prospective study to evaluate the outcomes of ESD for colorectal tumors. In this post hoc analysis, a total of 54 local residual or recurrent colorectal tumors in 54 patients were included, and we analyzed the short-term and long-term outcomes of ESD for these lesions. RESULTS: The median size of the lesions was 16.0 (interquartile range [IQR] 11-25) mm. ESD was completed in 53 cases (98.1%) with a median procedure time of 65.0 min, but it was discontinued in one case because of submucosal cancer invasion. En bloc resection was achieved in 52 cases (96.3%), whereas R0 resection was achieved in 45 cases (83.3%). Intraoperative perforation was observed in four cases (7.4%) and delayed perforation in one (1.9%), but all cases could be managed conservatively. Delayed bleeding was not observed. There were no significant differences in short-term outcomes between the rectal and colonic lesions. There was no recurrence of the tumor during the median follow-up period of 60 (IQR 50-64) months. CONCLUSION: An analysis of our multicenter prospective study suggests that ESD is an effective salvage management for local residual or recurrent colorectal lesions.

Management of colorectal high-grade dysplasia or cancer resected by cold snare polypectomy: a multicenter exploratory study.

BACKGROUND: The clinical course and surveillance strategy for patients who undergo cold snare polypectomy (CSP) for high-grade dysplasia (HGD) or cancer is unclear. We investigated the management of colorectal HGDs and cancers following CSP. METHODS: This Japanese nationwide multicenter exploratory study was retrospectively conducted on patients who had undergone CSP for colorectal HGDs or cancers and follow-up colonoscopy at least once from 2014 to 2020. We investigated the detection rate of CSP scars, local recurrence rate (LRR), risk factors for local recurrence, and follow-up strategy. This study was registered with the University Hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN000043670). RESULTS: We included 155 patients with 156 lesions. CSP scars were identified in 22 (31.4%), 41 (54.7%), and 10 (90.9%) patients with curative, borderline, and non-curative resection, respectively. Among them, residual tumors were observed in one (4.5%), six (14.6%), and three (30.0%) cases, respectively. The total LRR was 13.7% (95% confidence interval: 6.8-23.8). R1 resection cases (either horizontal or vertical margins positive for tumors) were associated with local recurrence (p = 0.031). Salvage endoscopic and surgical resections were performed on 21 and 10 patients, respectively. Among them, the proportion of endoscopically suspected residual tumors was significantly higher (p < 0.001) in the residual tumor-positive group (100%) than in the residual tumor-negative group (28.6%). CONCLUSIONS: LRR after CSP for HGDs or cancers was 13.7% based on scar-identified cases. Salvage endoscopic or surgical resection should be performed according to the curability of the lesion and endoscopic findings during colonoscopic surveillance.

Endoscopic diagnosis of Helicobacter pylori gastritis using white light imaging and texture and color enhancement imaging.

Background and study aims Texture and color enhancement imaging (TXI) is a new image-enhanced endoscopy that augments subtle tissue differences and color changes in gastric mucosa. This study aimed to compare the usefulness of TXI and white light imaging (WLI) for diagnosing Helicobacter pylori gastritis. Patients and methods We retrospectively prepared one image set with 22 endoscopic images acquired by WLI and TXI from 60 consecutive patients individually. Five endoscopists independently reviewed the randomly displayed image sets and assessed the H. pylori infection status on endoscopy according to the Kyoto Classification of Gastritis. The primary endpoints were the accuracies of WLI and TXI in diagnosing H. pylori -active gastritis. The correlation of the endoscopic features with the three H. pylori infection statuses (current infection, past infection, and noninfection) was also evaluated. Results Diagnostic accuracy for active gastritis was significantly higher in TXI than in WLI (85.3 % vs. 78.7 %; P  = 0.034). All the specific endoscopic features associated with H. pylori infection statuses had a higher odds ratio with TXI than with WLI. Additionally, interobserver agreement among the five reviewers was higher in TXI than in WLI, except for one pair. Conclusions TXI may improve the endoscopic diagnosis accuracy for H. pylori infection.

Diagnostic Value of Adding Magnifying Chromoendoscopy to Magnifying Narrow-Band Imaging Endoscopy for Colorectal Polyps.

BACKGROUND & AIMS: This study examined the additional value of magnifying chromoendoscopy (MCE) on magnifying narrow-band imaging endoscopy (M-NBI) in the optical diagnosis of colorectal polyps. METHODS: A multicenter prospective study was conducted at 9 facilities in Japan and Germany. Patients with colorectal polyps scheduled for resection were included. Optical diagnosis was performed by M-NBI first, followed by MCE. Both diagnoses were made in real time. MCE was performed on all type 2B lesions classified according to the Japan NBI Expert Team classification and other lesions at the discretion of endoscopists. The diagnostic accuracy and confidence of M-NBI and MCE for colorectal cancer (CRC) with deep invasion (≥T1b) were compared on the basis of histologic findings after resection. RESULTS: In total, 1173 lesions were included between February 2018 and December 2020, with 654 (5 hyperplastic polyp/sessile serrated lesion, 162 low-grade dysplasia, 403 high-grade dysplasia, 97 T1 CRCs, and 32 ≥T2 CRCs) examined using MCE after M-NBI. In the diagnostic accuracy for predicting CRC with deep invasion, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for M-NBI were 63.1%, 94.2%, 61.6%, 94.5%, and 90.2%, respectively, and for MCE they were 77.4%, 93.2%, 62.5%, 96.5%, and 91.1%, respectively. The sensitivity was significantly higher in MCE (P < .001). However, these additional values were limited to lesions with low confidence in M-NBI or the ones diagnosed as ≥T1b CRC by M-NBI. CONCLUSIONS: In this multicenter prospective study, we demonstrated the additional value of MCE on M-NBI. We suggest that additional MCE be recommended for lesions with low confidence or the ones diagnosed as ≥T1b CRC. Trials registry number: UMIN000031129.

Long-term Outcomes After Endoscopic Submucosal Dissection for Large Colorectal Epithelial Neoplasms: A Prospective, Multicenter, Cohort Trial From Japan.

BACKGROUND & AIMS: To determine the long-term outcomes after colorectal endoscopic submucosal dissection (ESD), we conducted a large, multicenter, prospective cohort trial with a 5-year observation period. METHODS: Between February 2013 and January 2015, we consecutively enrolled 1740 patients with 1814 colorectal epithelial neoplasms ≥20 mm who underwent ESD. Patients with noncurative resection (non-CR) lesions underwent additional radical surgery, as needed. After the initial treatment, intensive 5-year follow-up with planned multiple colonoscopies was conducted to identify metastatic and/or local recurrences. Primary outcomes were overall survival, disease-specific survival, and intestinal preservation rates. The rates of local recurrence and metachronous invasive cancer were evaluated as the secondary outcomes. RESULTS: The 5-year overall survival, disease-specific survival, and intestinal preservation rates were 93.6%, 99.6%, and 88.6%, respectively. Patients with CR lesions had no metastatic occurrence, and patients with non-CR lesions had 4 metastatic occurrences. Kaplan-Meier curves revealed that overall survival and disease-specific survival rates were significantly higher in patients with CR lesions than in those with non-CR lesions (P > .001 and P = .009, respectively). Local recurrence occurred in only 8 lesions (0.5%), which were successfully resected by subsequent endoscopic treatment. Multiple logistic regression analyses revealed that piecemeal resection (hazard ratio, 8.19; 95% CI, 1.47-45.7; P = .02) and margin-positive resection (hazard ratio, 8.06; 95% CI, 1.76-37.0; P = .007) were significant independent predictors of local recurrence after colorectal ESD. Fifteen metachronous invasive cancers (1.0%) were identified during surveillance colonoscopy, most of which required surgical resection. CONCLUSIONS: A favorable long-term prognosis indicates that ESD can be the standard treatment for large colorectal epithelial neoplasms. CLINICAL TRIAL REGISTRATION NUMBER: UMIN000010136.

Clinical outcome of the delineation-without-negative-biopsy strategy in magnifying image-enhanced endoscopy for identifying the extent of differentiated-type early gastric cancer.

BACKGROUND: The histologic evaluation of biopsy samples collected from the surrounding mucosa has conventionally been used to determine the horizontal extent of early gastric cancer. Recently, optical delineation using magnifying image-enhanced endoscopy (IEE) has been considered an alternative method to histologic evaluation. This study aimed to assess the clinical outcome and efficacy of this method in identifying cancer margins. METHODS: Overall, 921 patients with 1018 differentiated-type early gastric tumors who underwent endoscopic submucosal dissection (ESD) were examined. Before ESD, the lesions were classified based on whether they have clear or unclear margins on magnifying IEE. When the lesions had clear margins, the marking dots were placed outside the margins without a negative biopsy. Successful delineation was defined as lesions with clear margins and accurate delineation based on histopathological examination. The primary outcome was the accuracy of optical delineation without a negative biopsy compared with histopathological diagnosis. Moreover, the clinicopathological factors associated with an unsuccessful delineation were assessed. RESULTS: Of 1018 lesions, 820 had a clear margin and 198 an unclear margin. Of 820 lesions with a clear margin, 817 and 3 had an accurate and inaccurate delineation, respectively, according to the histological examination. Accordingly, the accuracy rate of optical delineation was 99.6% (817/820). The significant independent factors associated with an unsuccessful delineation were absence of Helicobacter pylori infection after eradication, tumor size > 20 mm, and moderate differentiation. CONCLUSIONS: Optical delineation may be an alternative method to histological evaluation in lesions with a clear margin on magnifying IEE.

Randomized study of two endo-knives for the traction-assisted endoscopic submucosal dissection of early esophageal squamous cell carcinoma.

Needle-type devices, such as the DualKnife (Olympus, Tokyo, Japan), are widely used for traction-assisted esophageal endoscopic submucosal dissection (ESD) but require a prolonged operation time. An improved model of the ITknife (Olympus), the ITknife nano, may allow faster and easier ESD than the DualKnife. We conducted a randomized study to compare the performances of the DualKnife and the ITknife nano for traction-assisted esophageal ESD. Patients with early esophageal squamous cell carcinoma were eligible for this study. The primary outcome was the total procedure time. The secondary outcomes were submucosal dissection time, en bloc, and complete resection rates, perforation rate, and adverse events. Results Fifty patients were equally divided into two groups: the DualKnife group (D-group) and the ITknife nano group (I-group), and all underwent the assigned treatment. The I-group had significantly shorter total procedure time (36.8 vs. 60.7 min; P < 0.01) and submucosal dissection time (17.2 vs. 35.8 min; P < 0.01) than the D-group. The en bloc and complete resection rates were sufficiently high in both groups (100% and 100% in the D-group and 100% and 96% in the I-group, respectively). Significantly fewer hemostatic procedures due to intraoperative bleeding were performed in the I-group than in the D-group (0.2 vs. 1.4; P < 0.01). Delayed bleeding, perforation, or esophageal stricture did not occur in either group. The ITknife nano exhibited lower procedure time for traction-assisted esophageal ESD than the DualKnife, without increasing adverse events.

Second-generation narrow-band imaging to detect colorectal adenomas: A prospective study including community hospitals.

BACKGROUND AND AIM: It is unclear whether second-generation narrow-band imaging (NBI) improves colorectal adenoma detection in clinical practice. We aimed to evaluate the ability of NBI to detect adenomas in academic and community hospitals. METHODS: This observational, multicenter study was conducted in four academic and four community hospitals between July 2018 and April 2019. We enrolled patients aged ≥ 20 years who underwent colonoscopy for screening, polyp surveillance, or diagnostic workup. The primary endpoint was the adenoma detection rate (ADR) between NBI (NBI group) and white-light imaging colonoscopies (WLI group) after propensity score (PS) matching. RESULTS: Of 1831 patients analyzed before PS matching, the NBI and WLI groups included 742 and 1089 patients, respectively. After PS matching, 711 pairs from both groups were analyzed. ADR and the mean number of adenomas per patient did not differ significantly between the NBI and WLI groups (43.5% vs 44.4%, P = 0.71; 0.90 ± 1.38 vs 0.91 ± 1.40, P = 0.95, respectively). Academic hospitals showed higher ADR in the NBI group (60.5% vs 53.8%), whereas community hospitals showed higher ADR in the WLI group (35.8% vs 40.5%). In the NBI group, ADR was significantly higher among NBI-screening-experienced endoscopists than among NBI-screening-inexperienced endoscopists (63.2% vs 39.2%, P < 0.001). The mean number of flat and depressed lesions detected per patient was significantly higher with NBI than with WLI (0.62 ± 1.34 vs 0.44 ± 1.01, P = 0.035). CONCLUSIONS: Second-generation NBI could not surpass WLI in terms of ADR based on patient recruitment from both academic and community hospitals but improved the detection of easily overlooked flat and depressed lesions.

Computer-aided diagnosis system using only white-light endoscopy for the prediction of invasion depth in colorectal cancer.

BACKGROUND AND AIMS: Endoscopic treatment is recommended for low-grade dysplasia (LGD), high-grade dysplasia (HGD), and colorectal cancer (CRC) with submucosal (SM) invasion <1000 µm. However, diagnosis of invasion depth requires experience and is often difficult. This study developed and evaluated a novel computer-aided diagnosis (CAD) system to determine whether endoscopic treatment is appropriate for colorectal lesions using only white-light endoscopy (WLE). METHODS: We extracted 3442 images from 1035 consecutive colorectal lesions (105 LGDs, 377 HGDs, 107 CRCs with SM <1000 µm, 146 CRCs with SM ≥1000 µm, and 300 advanced CRCs). All images were WLE, nonmagnified, and nonstained. We developed a novel CAD system using 2751 images; the remaining 691 images were evaluated by the CAD system as a test set. The capability of the CAD system to distinguish endoscopically treatable lesions and untreatable lesions was assessed and compared with the results from 2 trainees and 2 experts. RESULTS: The CAD system distinguished endoscopically treatable from untreatable lesions with 96.7% sensitivity, 75.0% specificity, and 90.3% accuracy. These values were significantly higher than those from trainees (92.1%, 67.6%, and 84.9%; P < .01, <.01, and <.01, respectively) and were comparable with those from experts (96.5%, 72.5%, and 89.4%, respectively). Trainees assisted by the CAD system demonstrated a diagnostic capability comparable with that of experts. CONCLUSIONS: The CAD system had good diagnostic capability for making treatment decisions for colorectal lesions. This system may enable a more convenient and accurate diagnosis using only WLE.

Visceral Fat-Reducing Effect and Safety of Continuous Consumption of Beverage Containing Resistant Maltodextrin: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Clinical Trial.

Obesity is regarded as a global concern with increasing prevalence, most notably in developed countries. Metabolic syndrome is a predictor of cardiovascular disease and type 2 diabetes mellitus and is defined as the accumulation of multiple risk factors caused by abdominal visceral obesity. Resistant maltodextrin (RMD) is a soluble dietary fiber that has been shown to reduce visceral fat in long-term clinical trials when continuously administered at 10 g, three times daily. Herein, we evaluated the effects of long-term consumption of 5 g RMD three times daily. A total of 140 healthy adults were randomly assigned to two intervention groups for a 12-wk randomized, double-blind, placebo-controlled, parallel-group trial. Participants ingested a test beverage containing 5 g RMD or a placebo beverage without RMD. Interviews, anthropometric measurements, physiological examination, blood tests, and urinalyses were conducted at baseline and every 4 wk during the trial. Computed tomography scans were performed at baseline and at the end of week 8 and 12. Results showed that abdominal visceral fat area (VFA) significantly decreased in the test group from 105.33±26.83 cm2 at baseline to 101.15±24.33 cm2 at week 12. Further, a significant difference was observed in the VFA between the test and control groups (p<0.05), confirming the function of continuous RMD consumption in reducing abdominal visceral fat. Furthermore, neither serious adverse events nor adverse clinical findings were observed in the blood or urine tests following consumption of RMD, suggesting that continuous consumption of RMD containing beverages is safe.

Laparoscopic cholecystectomy for a cholelithiasis patient with an aberrant biliary duct of B5: a case report.

BACKGROUND: An aberrant biliary duct of segment 5 (B5) is a rare anomaly of the biliary tract. All anatomical anomalies of the biliary tract are risk factors for bile duct injury during surgery. We report a case of cholelithiasis with an aberrant B5 that was detected during a detailed preoperative imaging examination and treated with laparoscopic cholecystectomy. CASE PRESENTATION: A 69-year-old woman was admitted to the emergency room of our hospital with abdominal pain. She was diagnosed with cholelithiasis, and an aberrant B5 branching off the hepatic duct was suggested during preoperative imaging. Laparoscopic cholecystectomy was performed at our surgical department. There were no intra- or postoperative complications, and the patient was discharged on the fourth day after surgery. CONCLUSIONS: Laparoscopic cholecystectomy can be safely performed without intra- or postoperative complications in patients with cholelithiasis and an aberrant B5 if it is accurately diagnosed preoperatively.

Usefulness of cold polypectomy under linked color imaging.

Background and study aims Cold polypectomy is becoming popular for treatment of colon polyps due to its safety and convenience, but there is still the problem of tumor remnants. Because linked color imaging (LCI) improves polyp visibility, cold polypectomy under LCI is anticipated to reduce the tumor remnant rate. Therefore, we investigated the usefulness of this procedure. Patients and methods Fifty patients scheduled to undergo cold polypectomy for treatment of colon polyps < 10 mm and assumed to be adenomas were registered prospectively. After performing cold snare polypectomy (CSP) under LCI, biopsy was performed at two resection margin sites for each polyp to determine the tumor remnant rate. Results A total of 145 lesions were treated by CSP. Of the 139 lesions in which polyps were retrievable and diagnosed as adenomas pathologically, one lesion was recognized as a remnant adenoma on biopsy (remnant rate: 0.7 % [95 % CI: 0.0-4.4]). This remnant rate was extremely low. Treatment results were extremely promising given that en bloc resection, post-procedure bleeding, and perforation rates were 100 %, 0 %, and 0 %, respectively. Conclusion Cold snare polypectomy under LCI may be an effective treatment method capable of reducing the tumor remnant rate. This trial was approved by our Institutional Ethics Committee and registered at the University Hospital Medical Information Network (UMIN 000033690).

Comparison of endoscopic visibility and miss rate for early gastric cancers after Helicobacter pylori eradication with white-light imaging versus linked color imaging.

BACKGROUND AND AIM: We aimed to investigate whether linked color imaging (LCI) improves endoscopic visibility of early gastric cancers (EGC) after Helicobacter pylori eradication, which are often difficult to detect, and reduces the miss rate when compared with white-light imaging (WLI). METHODS: The visibility study used two images, one each with WLI and LCI, from 84 consecutive EGC after H. pylori eradication. Endoscopic visibility was evaluated using a visibility score and color difference (CD) value. To analyze miss rates, we studied a library of recorded videos using both WLI and LCI for 70 other consecutive patients after H. pylori eradication, among whom 19 had EGC. Endoscopic screening was done using the same protocol to map the entire stomach. Six endoscopists reviewed the videos in a randomized order. Miss rates of EGC were compared among the modalities. RESULTS: Mean [(±standard deviation) visibility scores with LCI were significantly higher than those with WLI (3.19 ± 0.84 vs 2.52 ± 0.98, P < 0.001), as were mean CD values (26.3 ± 9.1 vs 13.6 ± 6.3, P < 0.001). Miss rates of the six endoscopists were significantly lower with LCI than with WLI (30.7% vs 64.9%, P < 0.001). Both expert and trainee endoscopists had significantly better results with LCI than with WLI. CONCLUSIONS: Linked color imaging significantly improved the visibility of EGC after H. pylori eradication compared with WLI using both subjective and objective criteria. Furthermore, LCI significantly reduced miss rates of these lesions compared with WLI.

Enrichment technique to allow early detection and monitor emergence of KRAS mutation in response to treatment.

Sensitivity of cell-free circulating tumour DNA (ctDNA) assays is often hampered by the limited quantity of intact mutant nucleotide fragments. To overcome the issue of substrate limitation in clinical applications, we developed an enrichment method utilizing pyrrole-imidazole (PI) polyamides and their ability to bind the minor groove of B-DNA. We present here a proof-of-concept experiment to enrich specific mutant KRAS alleles with biotinylated PI polyamides. We investigated the clinical feasibility of incorporating PI polyamides to detect KRAS mutations in ctDNA from 40 colorectal cancer (CRC) patients, of whom 17 carried mutations in KRAS. After enriching ctDNA with those polyamides, we used digital PCR to detect several common KRAS codon 12 mutations. Enrichment by biotinylated PI polyamides improved the sensitivity of ctDNA analysis (88.9% vs. 11.1%, P < 0.01) in 9 non-metastatic mutation-positive patients. We observed no differences in performance for the 8 metastatic subjects (100% vs. 75%, P = 0.47). In the remaining 23/40 patients with wild type KRAS codon 12, no mutant alleles were detected with or without polyamide-facilitated enrichment. Enriching B-form of ctDNA with PI polyamides significantly improved the assay sensitivity in detecting KRAS mutations in non-metastatic CRC patient samples.

Efficacy of Endoscopic Resection and Selective Chemoradiotherapy for Stage I Esophageal Squamous Cell Carcinoma.

BACKGROUND & AIMS: Esophagectomy is the standard treatment for stage I esophageal squamous cell carcinoma (ESCC). We conducted a single-arm prospective study to confirm the efficacy and safety of selective chemoradiotherapy (CRT) based on findings from endoscopic resection (ER). METHODS: We performed a prospective study of patients with T1b (SM1-2) N0M0 thoracic ESCC from December 2006 through July 2012; 176 patients underwent ER. Based on the findings from ER, patients received the following: no additional treatment for patients with pT1a tumors with a negative resection margin and no lymphovascular invasion (group A); prophylactic CRT with 41.4 Gy delivered to locoregional lymph nodes for patients with pT1b tumors with a negative resection margin or pT1a tumors with lymphovascular invasion (group B); or definitive CRT (50.4 Gy) with a 9-Gy boost to the primary site for patients with a positive vertical resection margin (group C). Chemotherapy comprised 5-fluorouracil and cisplatin. The primary end point was 3-year overall survival in group B, and the key secondary end point was 3-year overall survival for all patients. If lower limits of 90% confidence intervals for the primary and key secondary end points exceeded the 80% threshold, the efficacy of combined ER and selective CRT was confirmed. RESULTS: Based on the results from pathology analysis, 74, 87, and 15 patients were categorized into groups A, B, and C, respectively. The 3-year overall survival rates were 90.7% for group B (90% confidence interval, 84.0%-94.7%) and 92.6% in all patients (90% confidence interval, 88.5%-95.2%). CONCLUSIONS: In a prospective study of patients with T1b (SM1-2) N0M0 thoracic ESCC, we confirmed the efficacy of the combination of ER and selective CRT. Efficacy is comparable to that of surgery, and the combination of ER and selective CRT should be considered as a minimally invasive treatment option. UMIN-Clinical Trials Registry no.: UMIN000000553.

Early gastric cancer diagnostic ability of ultrathin endoscope loaded with laser light source.

BACKGROUND: Conventionally, the low luminous intensity, low image resolution, and difficulty in operation have been reported with the ultrathin endoscope. However, it has markedly advanced recently. The improvement of the diagnostic ability is expected. AIM: To compare the early gastric cancer diagnostic ability of an ultrathin endoscope loaded with a laser light source and that of the conventional endoscope. METHODS: The target subjects were 375 consecutive patients who underwent endoscopy at our hospital for post-endoscopic submucosal dissection follow-up of gastric cancer from January to August 2018. During endoscopy, the ultrathin endoscope was used in 140 patients (37.3%), and the conventional endoscope was used in 235 patients (62.7%). Patient background was adjusted using the propensity score matching method, and gastric cancer detection ability was evaluated in the two groups. RESULTS: The gastric cancer detection rate was 7.8% in the ultrathin endoscope group and 7.0% in the conventional endoscope group, and the mean intragastric observation time was 4.1 ± 1.7 min in the ultrathin endoscope group and 4.1 ± 1.9 min in the conventional endoscope group, showing no significant differences between the groups. Moreover, the biopsy implementation rate was 31.8% in the ultrathin endoscope group and 41.1% in the conventional endoscope group, and the biopsy prediction rate was 17.9% and 13.2%, respectively, showing no significant differences between the groups. CONCLUSION: The gastric cancer diagnostic ability of the ultrathin endoscope loaded with a laser light source was comparable to that of the conventional endoscope. The observation time was also comparable. Thus, endoscopy using the ultrathin endoscope loaded with the laser light source would be the first option in screening examinations of gastric cancer due to its low invasion.