Due to traditional professional divisions, the practice of endoscopy by gastro-intestinal surgeons in China remains controversial. However, with the evolution of treatment philo-sophies, medical technology, and equipment advancements, a trend of integration between tradi-tional surgery and endoscopy is emerging. Gastrointestinal surgeons performing endoscopy can maxi-mize patient benefits, and they naturally possess advantages in conducting endoscopic procedures. It is recommended to further establish entry thresholds for surgeons to perform endoscopy, provide standardized endoscopic training for surgeons, and coordinate efforts at the administrative depart-ment. With the support of artificial intelligence, more patients can receive minimally invasive, indivi-dualized, and precise treatments.

Objective:To investigate the clinicopathological characteristics and prognostic factors of Siewert Ⅱ and Ⅲ adenocarcinoma of esophagogastric junction (AEG).Methods:The retrospetcive cohort study was conducted. The clinicopathological data of 399 patients with AEG who were admitted to Peking University People′s Hospital from January 1998 to December 2015 were collected. There were 318 males and 81 females, aged 66(range, 19-87)years. Observation indicators: (1) clinicopathological characteristics of Siewert Ⅱ and Ⅲ AEG; (2) follow-up and survival; (3) prognostic factors analysis. Patients were followed up by telephone interview and outpatient examination to detect postoperative survival up to December 2018. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was conducted using the t test. Measurement data with skewed distribution were represented as M(range), and comparison between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Kaplan-Meier method was used to draw survival curves and calculate survival rates. Log-rank test was used for survival analysis. Univariate and multivariate analyses were done using the COX proportional hazard model. Results:(1) Clinicopathological characteristics of Siewert Ⅱ and Ⅲ AEG. Of 399 patients, 198 cases were Siewert Ⅱ AEG and 201 cases were Siewert Ⅲ AEG. There were 130 cases undergoing transthoracic radical AEG surgery, 172 cases undergoing trans-abdominal proximal gastrectomy and 97 cases undergoing transabdominal total gastrectomy. The age, tumor diameter, cases with surgical method as transthoracic radical AEG surgery, transabdo-minal proximal gastrectomy and transabdominal total gastrectomy, the number of positive lymph nodes, cases in tumor TNM stage Ⅰ, Ⅱ, Ⅲ, Ⅳ were (65±10)years, (5.1±2.4)cm, 102, 68, 28, 17(range, 12?22), 20, 57, 117, 4 for patients with Siewert Ⅱ AEG, versus (62±12)years, (6.3±3.2)cm, 28, 104, 69,18(range, 14?27), 16, 41, 134, 10 for patients with Siewert Ⅲ AEG, showing significant differ-ences betweeen them ( t=2.83, ?3.82, χ2=66.97, U=17 407.05, 17 532.00, P<0.05). (2) Follow-up and survival. All 399 patients were followed up for 34(range, 2?160)months. The 5-year overall survival rate was 29.3% for patients with Siewert Ⅱ AEG, versus 37.0% for patients with Siewert Ⅲ AEG, showing no significant difference betweeen them ( χ2=1.46, P>0.05). The median survival time and 5-year overall survival rate were 29.0 months [95% confidence interval ( CI) as 23.4?34.6 months] and 22.9% for patients undergoing transthoracic radical AEG surgery, 43.0 months(95% CI as 33.9?52.1 months) and 34.7% for patients undergoing transabdominal proximal gastrectomy, 54.0 months (95% CI as 37.6?70.4 months)and 44.3% for patients undergoing transabdominal total gastrectomy, showing a significant difference in the survival among the 3 groups ( χ2=13.81, P<0.05). Of the 198 Siewert Ⅱ AEG patients, the 5-year overall survival rate was 24.6% for the 96 patients undergoing transabdominal surgery, versus 35.4% for the 102 patients undergoing transthoracic surgery, showing no significant difference in the survival between them ( χ2=3.10, P>0.05). Of the 201 Siewert Ⅲ AEG patients, the 5-year overall survival rate was 40.0% for the 173 patients undergoing transabdominal surgery, versus 16.1% for the 28 patients undergoing transthoracic surgery, showing a significant difference between them ( χ2=11.32, P<0.05). (3) Prognostic factors analysis. Results of univariate analysis showed that surgical method, pathological N staging, patholgical M staging were related factors for prognosis of Siewert Ⅱ and Ⅲ AEG ( hazard ratio=0.68, 1.25, 2.18, 95% CI as 0.54?0.86, 1.15?1.36, 1.28?3.73, P<0.05). Results of multivariate analysis showed that transthoracic approach, pathological stage N2?N3 and pathological stage M1 were independent risk factors for prognosis of Siewert Ⅱ and Ⅲ AEG ( hazard ratio=0.64, 1.25, 2.18, 95% CI as 0.51?0.80, 1.16?1.35, 1.28?3.70, P<0.05). Conclusions:Compared with Siewert Ⅲ AEG, Siewert Ⅱ AEG has a smaller tumor diameter, less positive lymph nodes, poorer prognosis. Transthoracic approach is preffered for the Siewert Ⅱ AEG. Transthoracic approach, pathological stage N2?N3 and pathological stage M1 are independent risk factors for prognosis of Siewert Ⅱ and Ⅲ AEG.

Objective:To analyze the progress and promotion effect of the national multidisciplinary team(MDT) pilot project of digestive system tumor diagnosis and treatment, for the reference in promoting the popularition of tumor MDT model.Methods:The data of MDT project evaluation forms of 231 digestive system tumor MDT pilot hospitals in 2018(July 2017 to June 2018), 2019(July 2018 to June 2019)and 2020(July 2018 to June 2019)were obtained. The MDT of digestive system tumors, the development of outpatient and inpatient MDT, the distribution of cases, and the management, charging and regional radiation of MDT in the pilot hospital were analyzed. Descriptive analysis and frequency analysis were used for all the data.Results:With pilot hospitals of missing data excluded, the number of pilot hospitals included in the analysis from 2018 to 2020 was 227, 224 and 224, respectively.The number of pilot hospitals carrying out digestive system tumor MDT increased from 174 in 2018 to 222 in 2020, the number of outpatient and inpatient MDT cases increased from 48 332 and 61 823 to 72 493 and 106 899 respectively, and the proportion of pilot hospitals implementing the MDT management system increased from 159 to 214. In 2020, the average expenses of outpatient and inpatient MDT were mainly 200-500 yuan, and 135(60.3%) pilot hospitals became the leading MDT hospitals in the region.Conclusions:The MDT pilot project of digestive system tumors in China has achieved remarkable results.For example, the number of pilot hospitals carrying out MDT keeps increasing year by year, and the pilot hospitals have played a leading role in the region. In order to accelerate the coverage of the tumor MDT model, the authors suggested that the hospitals should optimize MDT in terms of patient accessibility, optimize management mode, promote the medical insurance reimbursement, and strengthen regional influence.

The anastomotic vessels between the superior mesenteric artery and the inferior mesenteric artery are vital to maintain the blood supply of the anastomosis and residual colon after colectomy. However, current studies of anastomotic vessels are facing four major obstacles: confusing nomenclature, large variability in data, diversification of research methods and incomplete information records. The existence of marginal artery has been widely proved, and its significance for blood supply is well recognized by relevant studies. In contrast, the Riolan′s arch, whose connotations constantly changed over history, can not refer to a specific structure accurately. Researchers should abolish the controversial names such as Riolan′s arch, select appropriate research methods and record the anastomotic vessels in detail, so as to improve the comparability between different results. The study of anastomotic vessels can help us to identify potential vascular disease, select the appropriate surgical approach, and provide appropriate treatment of the vessels in the operating area, so as to provide a theoretical foundation and practical basis for fine surgical maneuvers.

The anastomotic vessels between the superior mesenteric artery and the inferior mesenteric artery are vital to maintain the blood supply of the anastomosis and residual colon after colectomy. However, current studies of anastomotic vessels are facing four major obstacles: confusing nomenclature, large variability in data, diversification of research methods and incomplete information records. The existence of marginal artery has been widely proved, and its significance for blood supply is well recognized by relevant studies. In contrast, the Riolan′s arch, whose connotations constantly changed over history, can not refer to a specific structure accurately. Researchers should abolish the controversial names such as Riolan′s arch, select appropriate research methods and record the anastomotic vessels in detail, so as to improve the comparability between different results. The study of anastomotic vessels can help us to identify potential vascular disease, select the appropriate surgical approach, and provide appropriate treatment of the vessels in the operating area, so as to provide a theoretical foundation and practical basis for fine surgical maneuvers.

Objective:To investigate clinicopathological characteristics and efficacy of conversion therapy in patients with metastatic gastric cancer.Methods:The clinicopathological and follow-up data of metastatic gastric cancer patients at the Department of Gastrointestinal Surgery of Peking University People's Hospital from Jan 2018 to Jun 2021 were retrospectively studied. Multivariate Logistic regression analysis was used to identify independent characteristics for pathological complete response (PCR). The influence of stage of metastatic gastric cancer and pathological response on prognosis were analyzed by Kaplan-Meier curve.Results:A total of 31 patients were enrolled, and 13 tumors located at the cardia or fundus, 8 at body, other 10 at pylorus or antrum . Baseline CT evaluation showed retroperitoneal lymph node metastasis in 10 cases, intraperitoneal metastasis in 10 cases, liver metastasis in 2 cases, adrenal and splenic metastasis in 1 case respectively, and multiple metastasis in 5 cases. After conversion therapy, 8 (26%) cases had pathological T0, 16 cases (52%) had pathological N0 and 7 cases (22%) had pathological complete response. Multivariate Logistic regression analysis showed retroperitoneal lymph node metastasis ( OR: 20.082, 95% CI: 2.141-188.315, P=0.009) was the only independent risk factor of PCR. Meanwhile, Kaplan-Meier curve showed pT0 improved disease-free survival significantly ( P=0.021). Conclusions:Metastatic gastric cancer patients with retroperitoneal lymph node metastasis alone had a tolerable conversion therapy effect. pT0 is a significant factor in improving prognosis.

Objective:To explore the effect of tumor deposit (TD) on the prognosis of patients with stage Ⅲ colon cancer after radical resection.Methods:The clinicopathological data of patients with stage Ⅲ colon cancer after radical surgery at the Department of Gastrointestinal Surgery, Peking University People's Hospital from Jan to Dec 2015 were analyzed collected. Clinicopathological characteristics such as tumor location, degree of differentiation, mismatch repair status, lymphatic and venous invasion, and preoperative CEA and CA19-9 levels were used to study the effect of TD on the postoperative survival of patients.Results:Among the 155 patients with stage Ⅲ colon cancer, 37 (23.9%) had tumor deposits. The incidence of tumor deposits was higher in patients with intravascular tumor thrombus and preoperative serum CA19-9 elevation ( χ2=9.567, P=0.002; χ2=11.561, P=0.003); Patients with tumor deposits had worse overall survival and disease-free survival than those without cancer nodules (OS: P=0.029, DFS: P=0.025). Multivariate COX analysis found that tumor deposit was an independent risk factor for postoperative overall survival and disease-free survival ( HR=1.990, 95% CI: 1.032-3.835, P=0.040; HR=2.416, 95% CI : 1.205-3.820, P=0.009). Conclusions:Tumor deposit is an independent risk factor affecting postoperative overall survival and disease-free survival in patients with stage Ⅲ colon cancer. For patients with lymph node metastasis, incorporating TD into TNM staging can more accurately predict the postoperative prognosis.

Objective:To investigate the short term efficacy of laparoscopic assisted transanal total mesorectal excision (taTME) for low rectal cancer.Methods:The prospective study was conducted. The clinicopathological data of 80 patients who underwent laparoscopic assisted taTME for low rectal cancer in 8 medical centers，including 27 cases in the First Affiliated Hospital of Jilin University，16 cases in the Daping Hospital of Army Medical University，15 cases in the Beijing Friendship Hospital of Capital Medical University，10 cases in the Peking University Cancer Hospital，7 cases in the Peking Union Medical College Hospital of Chinese Academy of Medical Sciences，2 cases in the Peking University People′s Hospital，2 cases in the Liaoning Cancer Hospital Institute，1 case in the Ruijin Hospital of Shanghai Jiaotong University School of Medicine，from August 2017 to September 2018 were collected. Observation indicators：(1) clinical data of enrolled patients；(2) surgical situations；(3) postoperative histopathological examination；(4)postoperative complications and hospitalization. Measurement data with skewed distribution were represented as M(range). Count data were described as absolute numbers and (or) percentages. Results:(1) Clinical data of enrolled patients：a total of 80 patients were selected for eligibility. There were 59 males and 21 females，aged from 53 to 79 years，with a median age of 61 years. (2）Surgical situations：all 80 patients underwent surgery successfully，including 73 cases undergoing low anterior resection，4 cases undergoing Hartmann operation，1 case undergoing intersphincteric and abdominoperineal resection，1 case undergoing other operations and 1 case missing operation information. Nineteen of the 80 patients underwent transabdominal and transanal operations simultaneously. The operation time of 80 patients was 255 minutes (range，211?305 minutes). Of 80 patients，77 cases had the volume of intraoperative blood loss ≤500 mL，3 cases had the volume of intraoperative blood loss >500 mL，44 cases underwent instrumental anastomosis，24 cases underwent manual anastomosis，12 cases were missing anastomosis information，66 cases had specimens been taken out through anus，2 cases had specimens been taken out through Pfannens-tiel incision，10 cases had specimens been taken out through other ways，2 cases were missing the information of specimens removal ways，57 cases underwent preventive stoma，32 cases under-went anal canal indwelling，30 cases underwent free of splenic flexure and 2 cases were converted to open surgery. (3) Postoperative histopathological examination：of 80 patients，68 cases had the integrity of mesorectal specimens with complete，5 cases had the integrity of mesorectal specimens with near complete，1 case had the integrity of mesorectal specimens with not complete，6 cases were missing the information of integrity of mesorectal specimens，1 case had rectal perforation，1 case had positive circumferential margin and 1 case had positive distal margin. The number of lymph node dissected and diameter of tumor were 12(range，9?16) and 3.0 cm(range，1.9?4.0 cm) of 80 patients. Four of 80 patients achieved pathological complete remission. Cases with tumor stage as T0 stage，Tis stage，T1 stage，T2 stage，T3 stage or T4 stage of the pT staging，cases with tumor stage as N0 stage，N1 stage or N2 stage of the pN staging，cases with tumor stage as M0 stage or M1 stage of the pM staging were 4，2，11，24，35，4，55，21，4，75，5 of 80 patients. (4) Postopera-tive complications and hospitalization：8 of 80 patients underwent anastomotic leakage，including 2 cases with grade A anastomotic leakage，4 cases with grade B anastomotic leakage and 2 cases with grade C anastomotic leakage.Seven of 80 patients underwent intestinal obstruction. The 2 cases with grade A anastomotic leakage were improved after symptomatic drug treatment，the 4 cases with grade B anastomotic leakage were improved after treatment with antibiotics or catheter drainage and the 2 cases with grade C anastomotic leakage were improved after operation. The duration of hospital stay of 80 patients was 14 days(range，11?21 days). No patient died during hospitalization.Conclusion:Laparoscopic assisted taTME for low rectal cancer is safe and feasible，which has a good short term efficacy.

Objective:To investigate the incidence and influencing factors of anastomotic leakage after anterior resection (AR) for rectal cancer.Methods:The retrospective case-control study was conducted. The clinicopathological data of 1 243 patients with rectal cancer who were admitted to 3 medical centers between August 2008 and July 2017 were collected, including 512 in the Beijing Friendship Hospital of Capital Medical University, 480 in the Cancer Hospital of Chinese Academy of Medical Sciences, 251 in the Peking University People′s Hospital. There were 734 males and 509 females, aged from 25 to 89 years, with an average age of 65 years. All patients underwent AR for rectal cancer. Observation indicators: (1) surgical situations and incidence of postoperative anastomotic leakage; (2) influencing factors for postoperative anastomotic leakage. Measurement data with skewed distribution were represented as M (range). Count data were represented as absolute numbers or percentages, and comparison between groups was analyzed using the chi-square test or Fisher exact probability. Univariate analysis was conducted using the chi-square test. Multivariate analysis was conducted using the Logistic regression model based on factors with P<0.10 in the univariate analysis. Results:(1) Surgical situations and incidence of postoperative anastomotic leakage: all the 1 243 patients with rectal cancer underwent successfully AR including 219 undergoing defunctioning stoma and 1 024 undergoing non-defunctioning stoma, of which 70 patients had postoperative anastomotic leakage, with a total incidence rate of 5.632%(70/1 243). The incidence rates of grade A anastomotic leakage, grade B anastomotic leakage, and grade C anastomotic leakage were 27.1%(19/70), 21.4%(15/70), 51.4%(36/70), respectively. (2) Influencing factors for postoperative anastomotic leakage: results of univariate analysis showed that gender, surgical procedure, volume of intra-operative blood loss, and pathological metastasis staging were related factors for anastomotic leakage after AR ( χ2=8.518, 6.548, 10.834, 4.501, P<0.05). Results of multivariate analysis based on factors with P<0.10 in the univariate analysis showed that male and volume of intraoperative blood loss≥100 mL were independent risk factors for anastomotic leakage after AR [ odds ratio ( OR)=2.250, 1.949, 95% confidence interval ( CI): 1.281-3.952, 1.142-3.324, P<0.05)]; defunctioning stoma was an independent protective factor for anastomotic leakage after AR ( OR=0.449, 95% CI: 0.201-1.001, P<0.05). Subgroup analysis on effects of defunctioning stoma versus non-defunctioning stoma on grade of anastomotic leakage showed that percentage of grade C anastomotic leakage for defunctioning stoma group was 14.3%(1/7), versus 55.6%(35/63) for non-defunctioning stoma group, with a significant difference between the two groups ( χ2=9.570, P<0.05). Conclusions:Male and volume of intraoperative blood loss≥100 mL are independent risk factors for anastomotic leakage after AR. Defunctioning stoma is an independent protective factor for anastomotic leakage after AR. For male patients and patients with large volume of intraoperative blood loss, defunctioning stoma is recommended to reduce the incidence of postoperative anastomotic leakage.

Objective:To investigate the efficacy and prognosis of three surgical methods for presacral recurrent rectal cancer (PRRC).Methods:A retrospective cohort study was carried out. Case inclusion criteria: (1) primary rectal cancer without distant metastasis and undergoing radical surgery; (2) patients undergoing radical surgery after the diagnosis of PRRC; (3) complete inpatient, outpatient and follow-up data. Clinical data of 47 patients meeting the above criteria who underwent operation at the Department of Gastrointestinal Surgery, The Peking University People's Hospital from January 2008 to December 2017 were reviewed and analyzed retrospectively. Of the 47 patients, 31 were male and 16 were female; the mean age was 57 years old; 9 (19.1%) were low differentiation or signet ring cell carcinoma, 38 (80.9%) were medium differentiation; 19 (40.4%) received neoadjuvant therapy. According to operative procedure, 22 patients were in the abdominal/abdominoperineal resection group, 15 in the sacrectomy group and 10 in the abdominosacral resection group. The operative data, postoperative data and prognosis were compared among the three groups. Survival curve was conducted using the Kaplan-Meier method, and log-rank test was used to compare survival difference among three groups.Results:There were no significant differences in baseline data among three groups (all P>0.05). All the 47 patients completed the radical resection successfully. The mean operation time was (4.7±2.1) hours, the median intraoperative blood loss was 600 ml, and the median postoperative hospitalization time was 17 days. Fifteen cases (31.9%) had perioperative complications, of which 3 cases were grade III-IV. There was no perioperative death. The mean operative time was (7.4±1.6) hours in the abdominosacral resection group, (4.9±1.6) hours in the abdominal/abdominoperineal resection group, and (3.0±1.1) hours in the sacroectomy group, with a significant difference ( F=25.071, P<0.001). There were no significant differences in intraoperative blood loss, postoperative hospitalization days and perioperative complications among the three groups (all P>0.05). The median follow-up period of all the patients was 24 months, 12 cases (25.5%) developed postoperative dysfunction. The incidence of postoperative dysfunction in the abdominosacral resection group was 5/10, which was higher than 4/15 in the sacrectomy group and 3/22 (13.6%) in the abdominoperineal resection group with statistically significant difference (χ 2=9.307, P=0.010). The 1-year and 3-year overall survival rates were 86.1% and 40.2% respectively. The 1-year overall survival rates were 86.0%, 86.7% and 83.3%, and the 3-year overall survival rates were 33.2%, 40.0% and 62.5% in the abdominal/abdominoperineal resection group, sacrectomy group and abdominosacral resection group, respectively, whose difference was not statistically significant (χ 2=0.222, P=0.895). Conclusions:Abdominal/abdominoperineal resection, sacrectomy and abdominosacral resection are all effective for PRRC. Intraoperative function protection should be concerned for patients undergoing abdominosacral resection.