Purpose: Lung cancer is frequently observed as a second primary malignancy following gastric cancer, yet the genetic causality between them remains uncertain. This study aims to evaluate the causal relationship between gastric and lung cancers using Mendelian randomization (MR) analysis. Materials and Methods: Single nucleotide polymorphisms associated with gastric and lung cancers were selected from genome-wide association study in East Asian and European populations as instrumental variables. The causal effects between gastric and lung cancers were evaluated using univariable and multivariable MR analysis, with the inverse variance weighted (IVW) method serving as the primary criterion. Heterogeneity and sensitivity analyses were performed to ensure the robustness of the findings. Results: Univariable MR analysis demonstrated that genetic susceptibility to gastric cancer in the European population was significantly associated with an increased risk of lung cancer (IVW: odds ratio [OR], 1.285; 95% confidence interval [CI], 1.072 to 1.541; p=6.83E-03), which was consistently validated in the East Asian population (IVW: OR, 1.356; 95% CI, 1.114 to 1.651; p=2.40E-03). Multivariable MR analysis further indicated that the significant positive causal relationship between gastric cancer and lung cancer persisted in both populations after adjusting for confounding factors (all p < 0.05). Conversely, no significant causal relationship was observed for the risk of developing gastric cancer following the diagnosis of lung cancer in either population (p > 0.05). Conclusion This study confirms that genetic susceptibility to gastric cancer increases the risk of lung cancer. This finding provides a theoretical basis for exploring the underlying biological mechanisms and suggests that enhancing lung cancer screening in patients with gastric cancer may be necessary to improve patient prognosis.

Objective:To compare the clinical efficacy and safety of different myotomy procedures during peroral endoscopic myotomy (POEM) for achalasia (AC).Methods:A retrospective study was conducted involving patients diagnosed as having achalasia and underwent POEM at Peking Union Medical College Hospital from April 2020 to October 2023. Patients were divided into conventional myotomy group, short myotomy group and full-thickness myotomy group according to myotomy length and depth. Outcomes including operation duration, procedure-related complications, efficacy and incidence of postoperative reflux esophagitis were compared between conventional vs. short, and conventional vs. full-thickness groups.Results:Among 70 patients, 26 underwent conventional myotomy, 19 short myotomy, and 25 full-thickness myotomy. The short myotomy group demonstrated significantly shorter procedure duration (72.89±20.57 min) compared to the conventional group (91.81±36.70 min, t=2.197, P=0.034). There were no statistically significant differences in procedure-related complications [26.3% (5/19) VS 34.6% (9/26), χ2=0.353, P=0.553], treatment efficacy [94.7% (18/19) VS 96.2% (25/26), χ2=0.052, P=0.820], or incidence of postoperative reflux esophagitis [50.0% (5/10) VS 41.7% (5/12), χ2=0.306, P=0.580] between the short and conventional myotomy groups. No statistically significant differences were observed between the conventional and full-thickness myotomy group in procedure duration (99.64±29.13 min VS 91.81±36.70 min, t=0.336, P=0.404), procedure-related complications [28.0% (7/25) VS 34.6% (9/26), χ2=0.259, P=0.611], treatment efficacy [96.0% (24/25) VS 96.2% (25/26), χ2=0.001, P=0.977], or incidence of postoperative reflux esophagitis [35.7% (5/14) VS 41.7% (5/12), χ2=0.022, P=0.883]. Conclusion:Short myotomy POEM achieves comparable efficacy to conventional myotomy with reduced operative time and no increased complication risk. Full-thickness myotomy demonstrates similar efficacy, operative duration, and safety to conventional myotomy.

Objective To explore the methods of continuing education for advanced endoscope operations by diges-tive specialists through the establishment and teaching effect evaluation of the ERCP(endoscope retrograde cholan-giopancreatography)introductory training mode.Methods A total of 26 trainees from 3 sessions of the ERCP intro-ductory training courses at Peking Union Medical College Hospital from September 2023 to September 2024 were in-cluded.The teaching effects of the training courses and its 5 modules were subjectively and objectively evaluated by questionnaires,on-site tests and evaluations by senior ERCP operators.Results Through the ERCP introductory training courses,the trainees'self-evaluated proficiency in duodenoscope structure(pre-training:2.4±2.4,post-training:8.2±1.5,P＜0.001),duodenoscope operation(pre-training:1.2±2.2,post-training:6.6±1.8,P＜0.001),papillary cannulation(pre-training:0.5±1.3,post-training:5.4±1.8,P＜0.001),intra-bile duct operation(pre-training:0.2±0.6,post-training:4.9±2.1,P＜0.001),and identification of intra-bile duct lesions(pre-training:1.7±2.1,post-training:6.0±2.0,P＜0.001)was significantly improved.The accuracy rate of the trainees'theoretical tests and picture recognition before training was 37.2％and then increased up to 62.8％after training.Before training,all trainees were considered by senior operators as not ready to start ERCP training on real patients,while after training,69.2％(18/26)of the trainees were considered ready to start ERCP training on real patients.Conclusions The multi-module ERCP introductory training courses have a significant effect in terms of laying a foundation for trainees to start ERCP training on patients and of providing a reference for the con-tinuing education mode of advanced endoscope operations for digestive specialists in China.

Objective:To compare the clinical efficacy and safety of different myotomy procedures during peroral endoscopic myotomy (POEM) for achalasia (AC).Methods:A retrospective study was conducted involving patients diagnosed as having achalasia and underwent POEM at Peking Union Medical College Hospital from April 2020 to October 2023. Patients were divided into conventional myotomy group, short myotomy group and full-thickness myotomy group according to myotomy length and depth. Outcomes including operation duration, procedure-related complications, efficacy and incidence of postoperative reflux esophagitis were compared between conventional vs. short, and conventional vs. full-thickness groups.Results:Among 70 patients, 26 underwent conventional myotomy, 19 short myotomy, and 25 full-thickness myotomy. The short myotomy group demonstrated significantly shorter procedure duration (72.89±20.57 min) compared to the conventional group (91.81±36.70 min, t=2.197, P=0.034). There were no statistically significant differences in procedure-related complications [26.3% (5/19) VS 34.6% (9/26), χ2=0.353, P=0.553], treatment efficacy [94.7% (18/19) VS 96.2% (25/26), χ2=0.052, P=0.820], or incidence of postoperative reflux esophagitis [50.0% (5/10) VS 41.7% (5/12), χ2=0.306, P=0.580] between the short and conventional myotomy groups. No statistically significant differences were observed between the conventional and full-thickness myotomy group in procedure duration (99.64±29.13 min VS 91.81±36.70 min, t=0.336, P=0.404), procedure-related complications [28.0% (7/25) VS 34.6% (9/26), χ2=0.259, P=0.611], treatment efficacy [96.0% (24/25) VS 96.2% (25/26), χ2=0.001, P=0.977], or incidence of postoperative reflux esophagitis [35.7% (5/14) VS 41.7% (5/12), χ2=0.022, P=0.883]. Conclusion:Short myotomy POEM achieves comparable efficacy to conventional myotomy with reduced operative time and no increased complication risk. Full-thickness myotomy demonstrates similar efficacy, operative duration, and safety to conventional myotomy.

Objective:To assess the efficacy of endoscopic transmural drainage, transpapillary drainage and their combination in reducing cyst recurrence in patients with disconnected pancreatic duct syndrome (DPDS).Methods:A retrospective study was conducted involving 22 patients diagnosed as having DPDS in Peking Union Medical College Hospital from January 2018 to December 2022. Patient data including clinical information, imaging characteristics, drainage technique, complications, and outcomes were extracted from the medical records and telephone follow-up.Results:There were 27 endoscopic treatments in 22 patients, which were categorized into 3 groups based on the procedural approach: transmural in 11 cases, transpapillary in 8, and the combination of both in 8. The combined drainage group exhibited a significantly higher drainage success rate (100.0%, 8/8) compared with the transpapillary group (50.0%, 4/8, P=0.012), with no significant difference compared with the transmural group [90.9% (10/11), P=0.621]. The one-year recurrence rate was significantly lower in the combined drainage group [0.0% (0/8)] than that in the transmural drainage group [55.6% (5/9), P=0.018], and transpapillary drainage alone [42.9% (3/7)] though it did not reach significance ( P=0.085). No significant differences were observed in treatment success rate [45.5% (5/11), 75.0% (6/8) and 87.5% (7/8), H=3.890, P=0.143], or complication incidence [54.5% (6/11), 75.0% (6/8) and 25.0% (2/8), H=3.909, P=0.142]. Conclusion:Transmural drainage combined with pancreatic duct stent placement results in satisfactory drainage of cystic fluid in the short term and significantly reduces one-year recurrence among patients with DPDS.

Objective:To evaluate the diagnostic value of rapid on-site evaluation (ROSE) performed by endoscopists for solid pancreatic lesions requiring tissue for immunohistochemistry (IHC) staining with different approach of endoscopic ultrasound-guided tissue acquisition (EUS-TA).Methods:After screening 1 573 cases who underwent EUS-TA operation at the Endoscopy Center of Peking Union Medical College Hospital between August 2018 and October 2022, a total of 65 cases of solid pancreatic lesions whose diagnosis rely on IHC staining was collected and summarized with clinical data of each case. Among 65 cases, there were 46 cases of pancreatic neuroendocrine tumors (PNETs), 13 cases of pancreatic solid pseudo-papillary tumors (SPTs), and 6 cases of lymphomas and mesenchymal. Patients were categorized into ROSE group (36 cases) and non-ROSE group (29 cases) according to the presence or absence of endoscopists performed ROSE during EUS-TA operation. They were further divided into subgroups of FNA-ROSE (26 cases), FNB-ROSE (10 cases), FNA-non-ROSE (24 cases) and FNB-non-ROSE (5 cases) according to the type of EUS-TA. Diagnostic accuracy and IHC success rate were compared between different groups and subgroups. Binomial logistic multifactorial regression analysis was used to evaluate the influence of ROSE and EUS-TA type on diagnostic accuracy and IHC success rate.Results:There were no statistically significant differences between ROSE group and non-ROSE group in terms of age, gender, bilirubin level, CA19-9 level, lesion site, lesion size, composition ratio of diagnosis, and surgical rate. The differences in mean size of lesions, needle gauge, location of puncturation, and number of needle pass between subgroups were not statistically significant. The diagnostic accuracy was 88.9% in ROSE group and 79.3% in non-ROSE group, and the difference between the two groups was statistically significant ( P=0.023). The diagnostic accuracy of FNA-ROSE group was higher than that of FNA-non-ROSE group (88.5% vs 75.0%), but the difference was not statistically significant ( P>0.100). The differences in diagnostic accuracy and success rate of IHC between FNB-ROSE group and FNB-non-ROSE group were not statistically significant. Binomial logistic multifactorial regression analysis did not reveal any independent influences on diagnostic accuracy. Conclusions:ROSE performed by endoscopists improved diagnostic accuracy of EUS-TA in solid pancreatic lesions requiring IHC staining, and therefore is potentially valuable for improving the diagnostic efficiency of EUS-TA for such diseases.

Objective:To explore the clinical characteristics and outcomes of type 2 autoimmune pancreatitis (AIP) and compare with type 1 AIP.Methods:Clinical data of the patients diagnosed with type 2 AIP by the International Consensus on diagnostic criteria of AIP at Peking Union Medical College Hospital from January 2001 to December 2022 were retrospectively analyzed, and type 1 AIP patients diagnosed in Peking Union Medical College Hospital from January 1985 to December 2016 were collected as controls. The clinical symptoms, treatments and follow-ups were analyzed.Results:A total of 25 patients with type 2 AIP were included, of which 16 cases (64.0%) were pathologically confirmed cases (13 cases by endoscopic ultrasound puncture, 2 cases by surgery, and 1 case by interventional puncture), and 9 cases (36.0%) were suspected. The average age of onset was 40 years old. Most patients ( n=23, 92.0%) had abdominal pain along with emaciation to a various degree. Among them, 3 cases primarily presented as acute pancreatitis. Two cases were diagnosed after surgery for pancreatic masses. Eighteen cases were complicated with inflammatory bowel disease, including 16 cases with ulcerative colitis, one case with Crohn's disease, and one case with indeterminate colitis. All patients had typical imaging manifestations, including 13 cases (52.0%) with diffuse pancreatic enlargement, 12 cases (48.0%) with focal or multifocal pancreatic lesions, and 5 cases (20.0%) with simultaneous focal pancreatic masses and diffuse enlargement. All patients had normal serum IgG4 levels, anti-neutropil cytoplasmic antibodies (ANCA) positivity rate was 35.3% (6/17), and anti-nuclear antibody (ANA) positivity rate was 29.2% (7/24). Two surgical patients recovered well after surgery, and the other patients all achieved clinical and imaging relief after hormone therapy, and no recurrence was seen during follow-up. Compared with type 1 AIP, type 2 AIP had younger onset age, main manifestation as abdominal pain without jaundice, rare involvement with extra-pancreatic organs, the lesions mainly located in the intestine and normal IgG4 level with statistically significant differences. The recurrence rate of type 2 AIP was lower than that of type 1 AIP (0 vs 16%). Conclusions:Type 2 AIP has different clinical characteristics from type 1 AIP. Due to the lack of specific serum markers, the diagnosis is more difficult. It responds well to glucocorticoids and has a low recurrence rate.

To explore the application value of endoscopic ultrasound fine-needle aspiration (EUS-FNA) and endoscopic retrograde cholangiopancreatography (ERCP) in the diagnosis and treatment ofpatients with pancreatic cancer combined with obstructive jaundice.

Objective:To compare the efficacy of oral sulfate solution (OSS) and polyethylene glycol (PEG) electrolyte powder for colonoscopy bowel preparation.Methods:A total of 283 randomized patients from 9 centers in China taking OSS ( n=143) or PEG ( n=140) using two-day split bowel preparation regimen received colonoscopy and assessment. The primary index was the bowel preparation success rate [global Boston bowel preparation scale (BBPS)≥ 6 by independent assessment center]. Secondary indices included BBPS global and segmental scores, investigator satisfaction (5-point Likert scale) with the quality of bowel preparation, patient satisfaction assessed by questionnaires, and patient tolerance assessed by Sharma scale. Compliance and safety were compared between the two groups. Results:The bowel preparation success rates were 100.0% for OSS and 99.3% for PEG [adjusted difference 0.7% (95% CI: -5.3% - 6.7%), P<0.001 for non-inferiority]. The BBPS global score in OSS group was significantly higher than that in PEG group (8.1 VS 7.7, P<0.001). The segment BBPS scores were also higher in OSS group than those in PEG group for all 3 segments (right colon: 2.4 VS 2.3, P=0.002; transverse colon: 2.8 VS 2.7, P=0.018; left colon: 2.8 VS 2.7, P=0.007). Investigator Likert score in the OSS group was significantly higher than that in the PEG group (2.6 VS 2.3, P<0.001). There was no significant difference in compliance between OSS and PEG, except for the second dose (90.9% VS 82.6%, P=0.039). There was no significant difference in patient satisfaction, Sharma score or proportion of patients with tolerance-related symptoms between the two groups. Safety was comparable between the two groups, and all adverse events were mild to moderate. Conclusion:OSS has comparable efficacy with PEG, with higher BBPS scores in all segments, better investigator satisfaction, better compliance in split dose, and comparable patient tolerance and safety.

Objective:To investigate the predictive value of mucosal vascular pattern (MVP) in colonic epithelial proliferation of patients with ulcerative colitis (UC) under narrow-band imaging (NBI) colonoscopy.Methods:From December 1, 2012 to January 31, 2015, 42 patients with UC visiting Peking Union Medical College Hospital and receiving NBI colonoscopy were selected. The images of 119 colorectal lesions of all the patients under the conventional white light and NBI endoscopy were collected and at least one biopsy of each lesion was obtained for histological assessment. All the endoscopic images were randomly allocated to one endoscopist (associated chief physician) for the MVP and the Mayo endoscopic score (MES) assessment. The degree of mucosal inflammation was graded from 0 to 4 according to the histological colitis score. The degree and distribution of Ki-67 expression were evaluated by immunohistochemical staining. Student-Newman-Keuls (SNK)- q test and Spearman rank correlation analysis were used for statistical analysis. Results:Under NBI colonoscopy, the MVP of patients with UC was divided into clear type, obscure type and absent type. According to the morphology of mucosal glandular duct, the absent type was divided into crypt opening subtype and villous subtype. There was a positive correlation between MVP under NBI mode and the MES under white light mode ( r=0.80, P<0.001). The Ki-67 staining indexes of MVP obscure type, absent type, crypt opening subtype and villous subtype of absent type were all higher than that of MVP clear type (30.3±12.8, 45.9±12.5, 45.5±12.1 and 46.3±13.1 vs. 15.6±7.3), and the differences were statistically significant (SNK- q test, all P<0.001); and the Ki-67 staining indexes of MVP absent type, crypt opening subtype and villous subtype of MVP absent type were all higher than that of MVP obscure type, and the differences were statistically significant (SNK- q test, all P<0.001). There was a positive correlation between the MVP type under NBI colonoscopy and the distribution of Ki-67 expression ( r=0.49, P<0.001). The Ki-67 staining indexes of inflammation grade 2, 3 and 4 were higher than that of grade 1 (28.8±10.9, 40.2±11.6 and 49.5±10.3 vs. 17.1±8.4), and the difference was statistically significant (SNK- q test, all P<0.001); the Ki-67 staining indexes of inflammation grade 3 and 4 were higher than that of grade 2, and Ki-67 staining index of inflammation grade 4 was higher than that of grade 3, and the differences were statistically significant (SNK- q test, all P<0.001). The distribution of Ki-67 expression was positively correlated with the degree of histological inflammation ( r=0.56, P<0.001). Conclusions:The MVP under NBI colonoscopy may indirectly predict the colonic epithelial proliferation of patients with UC, which may be closely related to the degree of mucosal inflammation.