In recent years,the incidence of gastric cancer has been decreasing year by year in the world,but the incidence of adenocarcinoma of esophagogastric junction (AEG) has shown a significant upward trend,especially in western countries such as Europe and America.The prognosis of AEG is poor,therefore,it is extremely necessary to establish AEG's best diagnosis and treatment strategies to improve the long-term outcome of AEG.Nowadays,the most commonly used AEG classification is the Siewert classification proposed by German scholars in 1987,which is based on the anatomical features of the esophagogastric junction.It provides guidance for the choice of surgical methods.Compared with European and American countries,Siewert type Ⅱ or type Ⅲ are more common in Asian countries,and are mainly treated as the proximal gastric cancer.Compared with gastric tumors in other areas,AEG has obvious differences and specialities in anatomy,physiology and pathology,and there is still much controversy in the field of surgical and comprehensive treatment.

Gastric cancer is one of the most common malignant tumors in the world, and its incidence and mortality are among the top of malignant tumors in China. Since Kitano et al com-plete the first laparoscopic radical gastrectomy for gastric cancer in the world in 1992, the laparos-copic technology has developed rapidly. After more than 30 years of exploration and practice, the clinical diagnosis and treatment of gastric cancer in China has also made considerable progress. A large number of clinical studies at home and abroad have confirmed that laparoscopic radical gas-trectomy is no less effective than traditional open surgery in the short and long term. Laparoscopic radical gastrectomy has the characteristics of less trauma, faster recovery of gastrointestinal func-tion, less postoperative pain, and shorter average hospital stay. It has gradually replaced open surgery as the mainstream surgical method for gastric cancer. As the concept of surgical treatment for gastric cancer continues to update, emerging minimally invasive technologies continue to emerge, including robotic surgery systems and indocyanine green tracing technology, which are increasingly used in gastric cancer surgery, making gastric cancer surgery more minimally invasive and accurate, the quality of perigastric lymph node dissection and the domestic gastric cancer surgery technology further improving. Based on the relevant research at home and abroad, the authors review and summarize the latest progress in recent years with the topic of minimally invasive surgery for gastric cancer, aiming to systematically describe the current situation and future prospects of gastric cancer surgery. It is believed that in the future, the clinical diagnosis and treatment of gastric cancer in China will be more standardized, minimally invasive and accurate, more high-quality multicenter clinical research will be carry out and the diagnosis and treatment of gastric cancer will be further improved in China.

Objective:To investigate the surgical techniques and advantages of Ti-Robot-assisted surgery for pelvic fragility fractures in the elderly.Methods:A retrospective review was performed on geriatric patients presenting with pelvic fractures at the Orthopedics Department of Trauma, China-Japan Union Hospital of Jilin University from September 2019 to December 2022. Minimally invasive procedures were executed with the assistance of the Ti-Robot, and the therapeutic outcomes were appraised. The cohort comprised 24 patients aged ≥60 years, consisting of 6 men and 18 women, with a mean age of 66.1±4.9 years (range, 60-77 years). Fourteen patients sustained high-energy trauma, while 10 encountered low-energy trauma. Fracture classification utilized the FFP system proposed by Rommens and Hofmann. The cohort included 20 patients with FFP II fractures (5 males, 15 females; 4 of type IIa, 12 of type IIb, and 4 of type IIc) and 4 patients with FFP III fractures (1 male, 3 females; all type IIIa). The Matta standard assessment scale gauged fracture reduction, while the Gras classification, with Ti-Robot assistance, assessed screw positioning. Postoperative functionality was holistically assessed based on the Majeed quantitative evaluation system, focusing on pain intensity, sitting, standing, walking, and daily activities. The visual analogue scale (VAS) gauged pain levels in patients with type II fractures, pre and 72 hours post-surgery.Results:According to the Matta standard assessment scale, postoperative fracture reduction quality in 24 elderly patients showed 18 as excellent, 4 as good, and 2 as fair, yielding a 92% (22/24) combined excellent and good rate. Based on the Gras classification, 52 screws were rated as excellent and 7 as good, achieving a 100% positive rate. Utilizing Majeed's modified pelvic fracture evaluation system, postoperative functional recuperation revealed 19 patients as excellent and 5 as good. There were no reports of severe internal disease exacerbations, neurological manifestations, infections, or intraoperative extensive hemorrhaging, with all patients remaining stable. Fractures exhibited robust healing during follow-ups, averaging a recovery time of 3.5±0.7 months (range, 3-5 months). The VAS for 20 patients with FFP type II fractures decreased from 6.3±2.0 pre-surgery to 4.1±1.4 post-surgery ( t=6.14, P=0.003), signifying substantial pain mitigation. Conclusion:In the elderly with pelvic fragility fractures, particularly type II, securing with channel screws is viable. The Ti-Robot-assisted minimally invasive approach is advocated due to its potential to diminish surgical risks and expedite postoperative recuperation.

Objective:To investigate the clinical efficacy of Later-cut overlap anastomosis versus Roux-en-Y anastomosis in laparoscopic total gastrectomy.Methods:The propensity score matching and retrospective cohort study was conducted. The clinicopathological data of 1 804 patients with gastric cancer who underwent laparoscopic total gastrectomy in Fujian Medical University Union Hospital from January 2014 to March 2019 were collected. There were 1 346 males and 458 females, aged from 18 to 91 years, with a median age of 63 years. Of 1 804 patients, 100 undergoing Later-cut overlap anastomosis for digestive tract reconstruction in totally laparoscopic total gastrectomy and 1 704 undergoing Roux-en-Y anastomosis in laparoscopic-assisted total gastrectomy were allocated into modified group and traditional group, respectively. Observation indicators: (1) the propensity score matching conditions and comparison of general data between the two groups after propensity score matching; (2) intraoperative and postoperative situations; (3) complications; (4) follow-up, including ① functional scales of European Organization for Research and Treatment of Cancer quality of life questionnaire-core 30 (EORTC-QLQ-C30) for two groups after propensity score matching, ② symptom scales of EORTC-QLQ-C30 for two groups after propensity score matching, ③ symptom scales of European Organization for Research and Treatment of Cancer quality of life questionnaire of stomach 22 (EORTC-QLQ-STO22) for two groups after propensity score matching, ④ subgroup analysis; (5) learning curve of Later-cut overlap anastomosis. Patients were followed up by outpatient examination, paying a visit, Email and telephone interview once every 3 months within postoperative 2 years and once every 6 months within postoperative 3-5 years to detect postoperative life quality up to December 2019. The propensity score matching was conducted by 1∶1 matching using the nearest neighbor method. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was done using the t test. Count data were represented as absolute numbers or percentages, and comparison between groups was analyzed using the chi-square test. Comparison of ordinal data between groups was analyzed using the nonparametric rank sum test. Measurement data with skewed distribution were represented as M ( P25, P75) or M (range), and comparison between groups was done using the U test. The cumulative sum curve was used to analysis minor changes between individual and overall data, with the equation of CUSUM=∑ n,i=1 ( x i- μ), x i as esophagojejunostomy time of individuals, μ as the average time of esophagojejunostomy, n as serial number of patients. Results:(1) The propensity score matching conditions and comparison of general data between the two groups after propensity score matching: 200 of 1 804 patients had successful matching, including 100 in the modified group and 100 in the traditional group respectively. Before propensity score matching, the gender (males or females), age, tumor diameter, cases with tumor located at upper, middle or total stomach (tumor location), cases with differentiated or undifferentiated tumor (tumor differentiation degree), level of preoperative Alb, cases in stage T1, T2, T3, T4a (T staging), cases in stage N0, N1, N2, N3 (N staging), cases in stage Ⅰ, Ⅱ, Ⅲ (Union International Control Cancer staging) were 62, 38, (55±13)years, 4.5 cm(1.5 cm, 7.5 cm), 22, 67, 11, 72, 28, (42±4)g/L, 36, 11, 39, 14, 58, 16, 8, 18, 44, 29, 27 of the modified group, versus 1 284, 420, (62±11)years, 6.5 cm(2.5 cm, 8.0 cm), 891, 675, 138, 1 392, 312, (39±7)g/L, 148, 200, 393, 963, 498, 517, 257, 432, 322, 604, 778 of the traditional group, showing significant differences in the above indicators between the two groups ( χ2=8.89, t=5.69, Z=2.75, χ2=35.31, 5.80, t=3.91, Z=-9.97, -5.44, -5.41, P<0.05). After propensity score matching, the above indicators were 62, 38, (55±13)years, 4.0 cm(1.5 cm, 7.5 cm), 22, 67, 11, 82, 18, (42±4)g/L, 36, 11, 39, 14, 58, 16, 8, 18, 44, 29, 27 of the modified group, versus 68, 32, (56±11)years, 4.0 cm(1.5 cm, 7.4 cm), 12, 74, 14, 87, 13, (41±5)g/L, 23, 18, 45, 14, 54, 18, 10, 18, 42, 40, 18 of the traditional group, showing no significant difference in the above indicators between the two groups ( χ2=0.79, t=0.30, Z=0.87, χ2=3.65, 0.95, t=1.49, Z=-0.94, 1.43, -0.50, P>0.05). (2) Intraoperative and postoperative situations: after propensity score matching, the operation time, volume of intraoperative blood loss, the number of lymph node dissected, time to the first flatus, time to fluid diet intake, duration of postoperative hospital stay, treatment expenses were (195±41)minutes, 72 mL(range, 5-125 mL), 44±15, (3.4±1.1)days, (4.1±1.3)days, (10.7±4.3)days, (74 299±20 102)yuan of the modified group, versus (192±78)minutes, 67 mL(range, 10-195 mL), 40±18, (3.7±1.2)days, (4.5±1.9)days, (14.0±9.2)days, (71 029±12 231)yuan of the the traditional group, respectively. There was no significant difference in the operation time, the number of lymph node dissected, time to the first flatus, time to fluid diet intake, or treatment expenses between the two groups ( t=0.35, 1.73, 1.84, 1.74, 1.38, P>0.05). There were significant differences in the volume of intraoperative blood loss and duration of postoperative hospital stay between the two groups ( Z=0.62, t=3.25, P<0.05). (3) Complications: three patients in the modified group had complications, including 2 cases of anastomotic leakage and 1 case of abdominal infection. Four patients in the traditional group had complications, including 2 cases of anastomotic leakage, 1 case of anastomotic hemorrhage, 1 case of abdominal infection. There was no significant difference in the complications between the two groups ( χ2=0.00, P>0.05). Patients with anastomotic leakage and abdominal infection were cured after conservative treatments including adequate drainage, nutritional support, anti-inflammation. Patients with anastomotic hemorrhage were cured after blood transfusion and hemostatic therapy. There was no perioperative death in either group. (4) Follow-up: 146 patients received life quality evaluation at postoperative 6 months, including 78 in the modified group and 68 in the traditional group. ① Functional scales of EORTC-QLQ-C30 for two groups after propensity score matching: the scores of overall health functioning, physical functioning, role functioning, cognitive functioning, emotional functioning, social functioning were 31(22, 48), 75±27, 77±21, 79±15, 80±21, 76±29 for the modified group, respectively, versus 38(22, 57), 77±30, 79±27, 82±30, 82±31, 78±30 for the traditional group, showing no significant difference between the two groups ( Z=0.46, t=0.39, 0.40, 0.66, 0.49, P>0.05). ② Symptom scales of EORTC-QLQ-C30 for two groups after propensity score matching: the scores of fatigue, nausea and vomiting, pain, dyspnea, hyposomnia, anorexia, constipation, diarrhea, financial difficulty were 75±22, 89±19, 82±19, 77±19, 90±23, 74±14, 67±27, 74±28, 61±29 for the modified group, respectively, versus 72±28, 88±23, 91±23, 72±19, 88±19, 79±29, 68±28, 72±23, 61±24 for the traditional group; there was no significant difference in the scores of fatigue, nausea and vomiting, dyspnea, hyposomnia, anorexia, constipation, diarrhea or financial difficulty between the two groups ( t=0.70, 0.26, 1.56, 0.49, 0.43, 0.20, 0.43, 0.09, P>0.05), while there was a significant difference in the score of pain ( t=2.48, P<0.05). ③ Symptom scales of EORTC-QLQ-STO22 for two groups after propensity score matching: the scores of dysphagia, chest pain or abdominal pain, gastroesophageal reflux, eating disorder, anxiety, dryness of mouth, taste disorder, appearance disturbance, hair loss were 11(6, 20), 13(4, 22), 9(4, 21), 11(7, 20), 23(11, 34), 24(10, 31), 11(5, 21), 19(11, 35), 11(6, 25) for the modified group, respectively, versus 16 (7, 31), 14 (6, 22), 7(5, 16), 11(6, 20), 22 (13, 29), 28 (12, 33), 9 (5, 17), 20 (10, 25), 13 (5, 23) for the traditional group; there was no significant difference in the scores of chest pain or abdominal pain, gastroesophageal reflux, eating disorder, anxiety, dryness of mouth, taste disorder, appearance disturbance, hair loss between the two groups ( Z=0.41, -0.01, 0.99, -0.03, 0.52, 0.46, -0.20, 0.44, P>0.05), while there was a significant difference in the score of dysphagia ( Z=-2.07, P<0.05). ④ Subgroup analysis: after propensity score matching, cases with no, mild, moderate, severe pain (degree of pain perception) for pain-related items in EORTC-QLQ-C30 were 49, 24, 4, 1 of the modified group, versus 43, 9, 14, 2 of the traditional group, showing a significant difference between the two groups ( Z=-2.519, P<0.05). (5)Learning curve of Later-cut overlap anastomosis. The cumulative sum curve for esophagojejunostomy time of the 100 patients in the modified group showed a inflection point at the 33th patient, so the 1st-33th patients were allocated into learning phase and the 34th-100th patients were allocated into stable phase. The operation time, anastomosis time, volume of intraoperative blood loss, the number of lymph node dissected, time to first flatus, time to postoperative liquid diet intake, duration of hospital stay, treatment expenses for patients in the learning phase were (216±60)minutes, (28±10)minutes, 70 mL(range, 10-204 mL), 41±17, (4.5±0.9)days, (5.0±0.8)days, (11.1±4.3)days, 68 722 yuan(range, 52 312-94 943 yuan), respectively, versus (189±51)minutes, (23±8)minutes, 65 mL(range, 5-200 mL), 43±16, (4.4±1.0)days, (5.3±1.1)days, (10.6±6.8)days, 67 380 yuan(range, 49 289-92 732 yuan) for patients in the stable phase. There were significant differences in the operation time and anastomosis time between the two groups ( t=2.27, 2.87, P<0.05). There was no significant difference in the volume of intraoperative blood loss, the number of lymph node dissected, time to first flatus, time to postoperative liquid diet intake, duration of hospital stay or treatment expenses between the two groups ( Z=0.57, t=0.69, 0.49, 1.39, 0.39, Z=0.69, P>0.05). Conclusion:Later-cut overlap anastomosis is a digestive tract reconstruction method after totally laparoscopic total gastrectomy, which can reduce the volume of intraoperative blood loss, relieve postoperative eating obstruction and pain and improve postoperative life quality of patients.

Objective To investigate the application value of indocyanine green (ICG) fluorescence imaging in lymphadenectomy of laparoscopic radical gastrectomy for gastric cancer.Methods The retrospective cohort study was conducted.The clinicopathological data of 702 patients with primary gastric cancer who underwent laparoscopic radical gastrectomy and D2 lymphadenectomy in the Fujian Medical University Uuion Hospital between April and December 2017 were collected.There were 517 males and 185 females,aged from 22 to 91 years,with an average age of 61 years.Of the 702 patients,39 using ICG fluorescence imaging in the surgery and 663 not using ICG fluorescence imaging were allocated into ICG group and non-ICG group,respectively.Observation indicators:(1) surgical situations and postoperative recovery;(2) postoperative complications;(3) average number of lymph node dissected and positive lymph nodes;(4) follow-up situations.The number of lymph node dissected in the first station (No.1-7 group) and second station (No.8-12 group) were analyzed respectively.Follow-up using outpatient examination and telephone interview was performed to detect complications of patients up to June 2018.Measurement data with normal distribution were represented as Mean±SD,comparison between groups was analyzed using the t test.Measurement data with skewed distribution were described as M (range),comparison between groups was analyzed using the Mann-Whitney U test.Count data were represented as absolute number or percentage,comparison between groups was analyzed using the chi-square test.Comparisons of ordinal data were analyzed by the Mann-Whitney U test.Results (1) Surgical situations and postoperative recovery:702 patients underwent successfully laparoscopic radical gastrectomy and D2 lymphadenectomy,without injuries of important vessels and adjacent organs,without combined multiple organs resection or conversion to open surgery.Of 39 patients in the ICG group,cases undergoing total radical gastrectomy,distal subtotal gastrectomy and proximal subtotal gastrectomy,cases with Roux-en-Y esophagojejunostomy,Billroth Ⅰ anastomosis,Billroth Ⅱ anastomosis,Roux-en-Y gastrojejunostomy and esophagogastric anastomosis,operation time,volume of intraoperative blood loss,time for out-of-bed activities,time to initial anal exsufflation,time to first fluid diet intake and duration of postoperative hospital stay were 21,16,2,21,3,13,2,0,(173±28) minutes,40 mL (range,5-200 mL),(2.1±0.6)days,(3.5±1.4)days,(4.8± 1.3)days,(8.6±3.6) days.The above indexes were 363,299,1,363,27,267,1,5,(174±41)minutes,50 mL(range,0-1 750 mL),(2.2±0.8)days,(3.4± 1.1) days,(4.6± 1.5) days,(9.4± 5.0) days in the non-ICG group.There were statistically significant differences in the surgical type and digestive reconstruction method (x2 =9.550,11.388,P＜ 0.05) and no statistically significant difference in the operation time,volume of intraoperative blood loss,time for out-of-bed activities,time to initial anal exsufflation,time to first fluid diet intake and duration of postoperative hospital stay (t =0.221,Z =-0.651,t =0.492,-0.826,-0.842,0.995,P＞0.05).(2) Postoperative complications:92 out of the 702 patients had postoperative complications,without death of complications.The incidence of complication was 15.38％(6/39) and 12.97％(86/663) in the ICG group and non-ICG group,with no statistically significant difference between the two groups (x2=0.188,P＞0.05).Six patients with complications (1 of Clavien-Dindo Ⅳ,2 of Clavien-Dindo Ⅲa,3 of Clavien-Dindo Ⅰ) in the ICG group and 86 (6 of Clavien-Dindo Ⅳ,16 of Clavien-Dindo Ⅲ,61 of Clavien-Dindo Ⅱ,3 of Clavien-Dindo Ⅰ) in the non-ICG group were cured after symptomatic treatment.(3) Average number of lymph node dissected and positive lymph nodes:the average number of lymph node dissected and positive lymph nodes was 37 (range,3-112) and 1 (range,0-68) of 702 patients,38 (range,24-70) and 2 (range,0-42) in the ICG group,37 (range,3-112) and 1 (range,0-68) in the non-ICG group,with no statistically significant difference between the two groups (Z=-1.454,-0.514,P＞0.05).Stratified analysis:the average number of No.1-7 group lymph nodes dissected and positive lymph nodes was 34 (range,16-67) and 2 (0-38) in the ICG group,33 (range,3-91) and 1 (range,0-56) in the non-ICG group.The average number of No.8-12 group lymph nodes dissected and positive lymph nodes was 11 (range,4-22) and 0 (range,0-13) in the ICG group,9 (range,0-31) and 0 (range,0-25) in the non-ICG group.There was a statistically significant difference in the average number of No.8-12 group lymph nodes dissected between the two groups (Z=-1.984,P＜0.05).There was no statistically significant difference in the average number of No.1-7 group lymph nodes dissected,positive No.1-7 group lymph nodes and the average number of positive No.8-12 group lymph nodes between the two groups (Z =-1.302,-0.463,-0.758,P＞0.05).(4) Follow-up situations:702 patients were followed up for 6-14 months,with a median time of 10 months.There was no readmission caused by postoperative complications in the two groups.Conclusion ICG fluorescence imaging in lymphadenectomy of laparoscopic radical gastrectomy for gastric cancer is beneficial to dissection of perigastric lymph nodes and increase number of lymph nodes dissected,but cannot increase operation time and incidence of postoperative complications.

Objective:To investigate the construction and application value of a predictive model for prolonged surgical duration in Da Vinci robotic radical gastrectomy for gastric cancer.Methods:The retrospective cohort study was conducted. The clinicopathological data of 534 patients who underwent Da Vinci robotic radical gastrectomy for gastric cancer in the Fujian Medical University Union Hospital from August 2016 to August 2021 were collected. There were 389 males and 145 females, aged (60±11)years. All 534 patients were randomly divided into the training dataset of 374 cases and the validation dataset of 160 cases with a ratio of 7∶3 based on random number method in the SPSS 25.0 software. Observation indicators: (1) incidence of prolonged surgical duration; (2) intraoperative and postoperative conditions in patients with prolonged surgical duration and without prolonged surgical duration; (3) complications in patients with prolonged surgical duration and without prolonged surgical duration; (4) analysis of risk factors influencing prolonged surgical duration; (5) construction and evaluation of an artificial neural network predictive model for pro-longed surgical duration. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and comparison between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers or per-centages, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Comparison of ordinal data was analyzed using the nonparametric test. Univariate and multivariate analyses were conducted using the Logistic regression model. Based on the results of univariate analysis, a multilayer perceptron was employed to train an artificial neural network pre-dictive model for prolonged surgical duration. The receiver operating characteristic (ROC) curve was drawn, and the area under curve (AUC), the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were used to assess the model′s performance. Results:(1) Incidence of prolonged surgical duration. Of 534 patients, 284 cases underwent total gastrectomy, and 250 cases underwent distal gastrectomy, with operation time of (206±42)minutes and (187±36)minutes, res-pectively. Cases with prolonged surgical duration and without prolonged surgical duration who under-went total gastrectomy were 41 and 243, and cases with prolonged surgical duration and without prolonged surgical duration who underwent distal gastrectomy were 40 and 210. The gender (male, female), age, body mass index (BMI), tumor diameter, tumor location (upper stomach, middle stomach, lower stomach, mixed type), cases with neoadjuvant therapy, cases with preoperative American Society of Anesthesiologists (ASA) score as 1, 2, 3, cases with clinical T staging as stage T1, stage T2, stage T3, stage T4a, cases with clinical N staging as stage N0, stage N1, stage N2, stage N3, cases with clinical TNM staging as stage Ⅰ, stage Ⅱ, stage Ⅲ, cases with surgical resection scope as total gastrec-tomy or distal gastrectomy, cases with digestive tract reconstruction method as Billroth-Ⅰ anasto-mosis, Billroth-Ⅱ anastomosis, Roux-en-Y anastomosis, cases with surgeon experiences as ≤20 cases or >20 cases were 61,20, (61±9)years, (24±3)kg/m2, 4.0(2.5, 5.0)cm, 34, 10, 33, 4, 1, 3, 73, 5, 3, 6, 26, 46, 14, 41, 19, 7, 5, 13, 63, 41, 40, 1, 33, 47, 5, 76 in the 81 patients with prolonged surgical duration, versus 328, 125, (60±11)years, (23±3)kg/m2, 3.5(2.0, 5.0)cm, 129, 71, 227, 26, 6, 45, 382, 26, 73, 100, 118, 162, 211, 180, 52, 10, 138, 108,207, 243, 210, 13,200, 240, 15, 438 in the 453 patients without prolonged surgical duration, showing significant differences in the BMI, clinical T staging, clinical N staging, clinical TNM staging ( t=-3.68, Z=-4.63, -5.53, -5.56, P<0.05), and no significant difference in the gender, age, tumor diameter, tumor location, preoperative ASA score, surgical resec-tion scope, digestive tract reconstruction method, and surgeon experiences ( χ2=0.29, t=-0.95, Z=-1.27, χ2=5.92, Z=-1.46, χ2=0.25, 1.35, 0.87, P>0.05). There was no significant difference in cases with neoadjuvant therapy between them ( P>0.05). (2) Intraoperative and postoperative conditions in patients with prolonged surgical duration and without prolonged surgical duration. The operation time, volume of intraoperative blood loss, the number of lymph nodes dissected, time to postopera-tive first ambulation, time to postoperative anal exhaust, time to postoperative first intake of liquid diet, time to postoperative first intake of semi-liquid diet, duration of postoperative hospital stay were (261±34)minutes, 50(30, 50)mL, 39±15, (2.3±0.6)days, (3.4±0.9)days, (4.1±1.2)days, (5.7±1.2)days, 8.0(7.0, 9.0)days in the 81 patients with prolonged surgical duration, versus (186±29)minutes, 30(20,50)mL, 42±14, (2.2±0.6)days, (3.4±0.8)days, (4.1±1.1)days, (5.7±1.4)days, 8.0(7.0, 9.0)days in the 453 patients without prolonged surgical duration, showing significant differences in operation time, volume of intraoperative blood loss ( t=-20.46, Z=-3.32, P<0.05), and no significant difference in the number of lymph nodes dissected, time to postoperative first ambulation, time to postopera-tive anal exhaust, time to postoperative first intake of liquid diet, time to first intake of semi-liquid diet, duration of postoperative hospital stay ( t=1.87, -0.87, -0.16, 0.28, 0.03, Z=-1.45, P>0.05). (3) Complications in patients with prolonged surgical duration and without prolonged surgical duration. The overall incidence of complications, incidence of surgical complications (abdominal infection, anastomotic fistula, abdominal bleeding, incision-related complications, intestinal obstruction, lymphatic fistula), incidence of medical complications (pulmonary infection, liver-related complications) were 22.22%(18/81), 0, 0, 2.47%(2/81), 0, 8.64%(7/81), 1.23%(1/81), 12.35%(10/81), 1.23%(1/81) in the 81 patients with prolonged surgical duration, versus 13.47%(61/453), 2.65%(12/453), 0.44%(2/453), 1.77%(8/453), 0.44%(2/453), 3.31%(15/453), 0, 7.28%(33/453), 1.55%(7/453) in the 453 patients without prolonged surgical duration, showing a significant difference in the overall incidence of complications ( χ2=4.18, P<0.05), and no significant difference in the incidence of abdo-minal infection, anastomotic fistula, abdominal bleeding, incision-related complications, intestinal obstruction, lymphatic fistula, liver-related complications ( P>0.05). There was no significant difference in the incidence of pulmonary infection between them ( χ2=2.38, P>0.05). (4) Analysis of risk factors influencing prolonged surgical duration. Results of univariate analysis showed that BMI ≥25 kg/m2, tumor located in the lower stomach, clinical T3-T4a stage, clinical N1-N3 stage were correlated factors influencing prolonged surgical duration in Da Vinci robotic radical gastrectomy for gastric cancer ( odds ratio=1.88, 0.40, 6.24, 6.51, 3.08, 3.39, 17.15, 95% confidence interval as 1.03-3.42, 0.21-0.76, 1.40-27.76, 1.50-28.30, 1.43-6.60, 1.29-8.92, 4.84-60.74, P<0.05). Results of multivariate analysis showed that BMI ≥25 kg/m2, clinical T3 stage, clinical N3 stage were independent risk factors influencing prolonged surgical duration in Da Vinci robotic radical gastrectomy for gastric cancer ( odds ratio=2.31, 4.97, 11.08, 95% confidence interval as 1.19-4.46, 1.05-23.55, 2.72-45.13, P<0.05). (5) Construction and evaluation of an artificial neural network predictive model for pro-longed surgical duration. The BMI, tumor location, clinical T staging, and clinical N staging were incorporated into a multilayer perceptron to construct an artificial neural network predictive model for prolonged surgical duration. Results of ROC curve showed that the AUC, accuracy, sensitivity, specificity, positive predictive value, negative predictive value of the predictive model in the training dataset were 0.73 (95% confidence interval as 0.68-0.78), 91.4%, 68.1%, 94.8%, 65.3%, 95.4%. The above indicators of the predictive model in the validation dataset 0.72 (95% confidence interval as 0.65-0.79), 88.1%, 67.6%, 93.7%, 74.2%, 91.5%. Conclusions:BMI ≥25 kg/m2, clinical T3 stage, clinical N3 stage are independent risk factors influencing prolonged surgical duration in Da Vinci robotic radical gastrectomy for gastric cancer. The artificial neural network predictive model con-structed based on BMI, tumor location, clinical T staging, and clinical N staging can effectively predict patients at high risk of prolonged surgical duration in Da Vinci robotic radical gastrectomy for gastric cancer.

Objective:To investigate the prognosis of patients with initially resectable gastric cancer liver metastasis (GCLM) who were treated by different modalities, and analyze the influencing factors for prognosis of patients.Methods:The retrospective cohort study was conducted. The clinicopathological data of 327 patients with initially resectable GCLM who were included in the database of a nationwide multicenter retrospective cohort study on GCLM based on real-world data from January 2010 to December 2019 were collected. There were 267 males and 60 females, aged 61(54,68)years. According to the specific situations of patients, treatment modalities included radical surgery combined with systemic treatment, palliative surgery combined with systemic treatment, and systemic treatment alone. Observation indicators: (1) clinical characteristics of patients who were treated by different modalities; (2) prognostic outcomes of patients who were treated by different modalities; (3) analysis of influencing factors for prognosis of patients with initially resectable GCLM; (4) screening of potential beneficiaries in patients who were treated by radical surgery plus systemic treatment and patients who were treated by palliative surgery plus systemic treatment. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and comparison between groups was conducted using the rank sum test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test. The Kaplan-Meier method was used to calculate survival rate and draw survival curve, and Log-Rank test was used for survival analysis. Univariate and multivariate analyses were conducted using the COX proportional hazard regression model. The propensity score matching was employed by the 1:1 nearest neighbor matching method with a caliper value of 0.1. The forest plots were utilized to evaluate potential benefits of diverse surgical combined with systemic treatments within the population. Results:(1) Clinical characteristics of patients who were treated by different modalities. Of 327 patients, there were 118 cases undergoing radical surgery plus systemic treatment, 164 cases undergoing palliative surgery plus systemic treatment, and 45 cases undergoing systemic treatment alone. There were significant differences in smoking, drinking, site of primary gastric tumor, diameter of primary gastric tumor, site of liver metastasis, and metastatic interval among the three groups of patients ( P<0.05). (2) Prognostic outcomes of patients who were treated by different modalities. The median overall survival time of the 327 pati-ents was 19.9 months (95% confidence interval as 14.9-24.9 months), with 1-, 3-year overall survival rate of 61.3%, 32.7%, respectively. The 1-year overall survival rates of patients undergoing radical surgery plus systemic treatment, palliative surgery plus systemic treatment and systemic treatment alone were 68.3%, 63.1%, 30.6%, and the 3-year overall survival rates were 41.1%, 29.9%, 11.9%, showing a significant difference in overall survival rate among the three groups of patients ( χ2=19.46, P<0.05). Results of further analysis showed that there was a significant difference in overall survival rate between patients undergoing radical surgery plus systemic treatment and patients undergoing systemic treatment alone ( hazard ratio=0.40, 95% confidence interval as 0.26-0.61, P<0.05), between patients undergoing palliative surgery plus systemic treatment and patients under-going systemic treatment alone ( hazard ratio=0.47, 95% confidence interval as 0.32-0.71, P<0.05). (3) Analysis of influencing factors for prognosis of patients with initially resectable GCLM. Results of multivariate analysis showed that the larger primary gastric tumor, poorly differentiated tumor, larger liver metastasis, multiple hepatic metastases were independent risk factors for prognosis of patients with initially resectable GCLM ( hazard ratio=1.20, 1.70, 1.20, 2.06, 95% confidence interval as 1.14-1.27, 1.25-2.31, 1.04-1.42, 1.45-2.92, P<0.05) and immunotherapy or targeted therapy, the treatment modality of radical or palliative surgery plus systemic therapy were independent protective factors for prognosis of patients with initially resectable GCLM ( hazard ratio=0.60, 0.39, 0.46, 95% confidence interval as 0.42-0.87, 0.25-0.60, 0.30-0.70, P<0.05). (4) Screening of potentinal beneficiaries in patients who were treated by radical surgery plus systemic treatment and patients who were treated by palliative surgery plus systemic treatment. Results of forest plots analysis showed that for patients with high-moderate differentiated GCLM and patients with liver metastasis located in the left liver, the overall survival rate of patients undergoing radical surgery plus systemic treatment was better than patients undergoing palliative surgery plus systemic treatment ( hazard ratio=0.21, 0.42, 95% confidence interval as 0.09-0.48, 0.23-0.78, P<0.05). Conclusions:Compared to systemic therapy alone, both radical and palliative surgery plus systemic therapy can improve the pro-gnosis of patients with initially resectable GCLM. The larger primary gastric tumor, poorly differen-tiated tumor, larger liver metastasis, multiple hepatic metastases are independent risk factors for prognosis of patients with initial resectable GCLM and immunotherapy or targeted therapy, the treatment modality of radical or palliative surgery plus systemic therapy are independent protective factors for prognosis of patients with initially resectable GCLM.