Objective:To investigate the correlation between whether the left colonic artery(LCA) is preserved intraoperatively and the incidence of severe low anterior resection syndrome(LARS) in patients with rectal cancer.Methods:Clinical data of 255 rectal cancer patients undergoing low anterior resection from Jan 2020 to Jan 2022 at the First Affiliated Hospital of Xi'an Jiaotong University were retrospectively analysed, and the occurrence of LARS in patients with or without preserving the LCA was compared.Results:The LARS scores and severity in patients with intact LCA were better than those without preserved LCA at 12 months postoperatively ( P=0.017, 0.002). Bowel function at 6 months versus 12 months postoperatively in both groups was mainly reflected in a reduction in the number of bowel movements per day ( P=0.003, 0.001) as well as a reduction in re-voiding of the bowel within 1 hour after defecation ( P<0.001, P=0.001). Univariate and multivariate analyses showed that the distance of the lower edge of the tumour from the anal verge was ≤6 cm ( OR=2.530, 95% CI:1.307-4.900, P=0.006), preoperative neoadjuvant therapy ( OR=13.968, 95% CI: 4.969-39.260, P<0.001), prophylactic stoma ( OR=4.051, 95% CI: 2.042-8.040, P<0.001) were also independent risk factors for severe LARS after anterior resection of rectal cancer, and preservation of the left colonic artery ( OR=0.283, 95% CI: 0.142-0.563, P<0.001) was a protective factor against severe LARS after low anterior resection in rectal cancer patients. Conclusions:Intraoperative preservation of the LCA reduces the incidence and severity of postoperative LARS in patients with rectal cancer undergoing anterior resection. The distance of the lower edge of thetumour from the anal verge and prophylactic stoma are independent risk factors affecting the occurrence of severe LARS after anterior resection of rectal cancer.

Objective:To investigate the correlation between whether the left colonic artery(LCA) is preserved intraoperatively and the incidence of severe low anterior resection syndrome(LARS) in patients with rectal cancer.Methods:Clinical data of 255 rectal cancer patients undergoing low anterior resection from Jan 2020 to Jan 2022 at the First Affiliated Hospital of Xi'an Jiaotong University were retrospectively analysed, and the occurrence of LARS in patients with or without preserving the LCA was compared.Results:The LARS scores and severity in patients with intact LCA were better than those without preserved LCA at 12 months postoperatively ( P=0.017, 0.002). Bowel function at 6 months versus 12 months postoperatively in both groups was mainly reflected in a reduction in the number of bowel movements per day ( P=0.003, 0.001) as well as a reduction in re-voiding of the bowel within 1 hour after defecation ( P<0.001, P=0.001). Univariate and multivariate analyses showed that the distance of the lower edge of the tumour from the anal verge was ≤6 cm ( OR=2.530, 95% CI:1.307-4.900, P=0.006), preoperative neoadjuvant therapy ( OR=13.968, 95% CI: 4.969-39.260, P<0.001), prophylactic stoma ( OR=4.051, 95% CI: 2.042-8.040, P<0.001) were also independent risk factors for severe LARS after anterior resection of rectal cancer, and preservation of the left colonic artery ( OR=0.283, 95% CI: 0.142-0.563, P<0.001) was a protective factor against severe LARS after low anterior resection in rectal cancer patients. Conclusions:Intraoperative preservation of the LCA reduces the incidence and severity of postoperative LARS in patients with rectal cancer undergoing anterior resection. The distance of the lower edge of thetumour from the anal verge and prophylactic stoma are independent risk factors affecting the occurrence of severe LARS after anterior resection of rectal cancer.

Chemotherapy resistance plays a pivotal role in the prognosis and therapeutic failure of patients with colorectal cancer(CRC).Cisplatin(DDP)-resistant cells exhibit an inherent ability to evade the toxic chemotherapeutic drug effects which are characterized by the activation of slow-cycle programs and DNA repair.Among the elements that lead to DDP resistance,O6-methylguanine(O6-MG)-DNA-meth-yltransferase(MGMT),a DNA-repair enzyme,performs a quintessential role.In this study,we clarify the significant involvement of MGMT in conferring DDP resistance in CRC,elucidating the underlying mechanism of the regulatory actions of MGMT.A notable upregulation of MGMT in DDP-resistant cancer cells was found in our study,and MGMT repression amplifies the sensitivity of these cells to DDP treatment in vitro and in vivo.Conversely,in cancer cells,MGMT overexpression abolishes their sensi-tivity to DDP treatment.Mechanistically,the interaction between MGMT and cyclin dependent kinase 1(CDK1)inducing slow-cycling cells is attainted via the promotion of ubiquitination degradation of CDK1.Meanwhile,to achieve nonhomologous end joining,MGMT interacts with XRCC6 to resist chemotherapy drugs.Our transcriptome data from samples of 88 patients with CRC suggest that MGMT expression is co-related with the Wnt signaling pathway activation,and several Wnt inhibitors can repress drug-resistant cells.In summary,our results point out that MGMT is a potential therapeutic target and predictive marker of chemoresistance in CRC.

Objective:To compare and evaluate recurrence patterns after robotic-assisted gastrectomy (RAG) versus laparoscopic-assisted gastrectomy (LAG).Methods:This was a retrospective cohort study of 2915 consecutive patients with gastric adenocarcinoma confirmed by postoperative histology as T1-4aN0-3M0, who had undergone minimally invasive radical gastrectomy at four large gastric cancer treatment centers (Fujian Medical University Union Hospital: 1426 patients; the First Affiliated Hospital, Nanchang University: 1108; Tianjin Medical University Cancer Institute and Hospital: 196; and First Affiliated Hospital of Xi'an Jiaotong University: 185 cases) between 1 January 2015 and 30 June 2019. 930 patients had undergone RAG (RAG group) and 1985 had undergone LAG (LAG group). We assessed the following characteristics: age, sex, body mass index, American Society of Anesthesiologists score, comorbidities, tumor size, extent of surgery, extent of lymph node dissection, pT, pN, year of surgery, and adjuvant chemotherapy, after propensity score matching (1:1). There were no significant differences in baseline clinical characteristics between the two groups formed by propensity score matching (837 in each group) (all P>0.05). The 3-year recurrence-free survival (RFS), recurrence pattern, and conditional RFS were compared. Results:We detected no significant differences in the overall recurrence rate at 3 years (128/837 [15.3%] vs. 141/837 [16.8%], P=0.387) or time to recurrence (15.7±8.1 months vs. 16.4±8.4 months, P=0.449) between the RAG and LAG groups. Peritoneal recurrence was the most common type of recurrence in both groups (55 [6.6%] vs. 69 [8.2%], P=0.524). The difference in 3-year RFS between the RAG and LAG groups was not statistically significant (83.2% vs. 82.5%, P=0.781). We found that age > 60 years, total gastrectomy, and worse pT stage and pN stage were independent risk factors for recurrence in the study patients (all P<0.05), whereas the surgical procedure (RAG or LAG) was not an independent risk factor for RFS ( P=0.242). The 3-year conditional RFS at various time points was comparable between the two groups (1 year postoperatively: 84.6% vs. 84.7%, P=0.793; 3 years postoperatively: 91.5% vs. 94.9%, P=0.647). Conclusions:In this multicenter study of patients with locally resectable gastric cancer, we demonstrated that RAG performed by surgeons at large gastric cancer centers is not inferior to LAG in 3-year recurrence rate or recurrence patterns.

Objective:To compare and evaluate recurrence patterns after robotic-assisted gastrectomy (RAG) versus laparoscopic-assisted gastrectomy (LAG).Methods:This was a retrospective cohort study of 2915 consecutive patients with gastric adenocarcinoma confirmed by postoperative histology as T1-4aN0-3M0, who had undergone minimally invasive radical gastrectomy at four large gastric cancer treatment centers (Fujian Medical University Union Hospital: 1426 patients; the First Affiliated Hospital, Nanchang University: 1108; Tianjin Medical University Cancer Institute and Hospital: 196; and First Affiliated Hospital of Xi'an Jiaotong University: 185 cases) between 1 January 2015 and 30 June 2019. 930 patients had undergone RAG (RAG group) and 1985 had undergone LAG (LAG group). We assessed the following characteristics: age, sex, body mass index, American Society of Anesthesiologists score, comorbidities, tumor size, extent of surgery, extent of lymph node dissection, pT, pN, year of surgery, and adjuvant chemotherapy, after propensity score matching (1:1). There were no significant differences in baseline clinical characteristics between the two groups formed by propensity score matching (837 in each group) (all P>0.05). The 3-year recurrence-free survival (RFS), recurrence pattern, and conditional RFS were compared. Results:We detected no significant differences in the overall recurrence rate at 3 years (128/837 [15.3%] vs. 141/837 [16.8%], P=0.387) or time to recurrence (15.7±8.1 months vs. 16.4±8.4 months, P=0.449) between the RAG and LAG groups. Peritoneal recurrence was the most common type of recurrence in both groups (55 [6.6%] vs. 69 [8.2%], P=0.524). The difference in 3-year RFS between the RAG and LAG groups was not statistically significant (83.2% vs. 82.5%, P=0.781). We found that age > 60 years, total gastrectomy, and worse pT stage and pN stage were independent risk factors for recurrence in the study patients (all P<0.05), whereas the surgical procedure (RAG or LAG) was not an independent risk factor for RFS ( P=0.242). The 3-year conditional RFS at various time points was comparable between the two groups (1 year postoperatively: 84.6% vs. 84.7%, P=0.793; 3 years postoperatively: 91.5% vs. 94.9%, P=0.647). Conclusions:In this multicenter study of patients with locally resectable gastric cancer, we demonstrated that RAG performed by surgeons at large gastric cancer centers is not inferior to LAG in 3-year recurrence rate or recurrence patterns.

Objective:To investigate the predictive value of Charlson comorbidity index (CCI) in the operative prognosis of colorectal cancer (CRC).Methods:The retrospective cohort study was conducted. The clinicopathological data of 1 337 CRC patients who underwent surgery in the First Affiliated Hospital of Xi'an Jiaotong University from January 2013 to February 2019 were collected. There were 774 males and 563 females, aged 62(range, 22?80)years. All patients were evaluated by CCI. Observation indicators: (1) clinicopathological characteristics of CRC patients undergoing operation; (2) follow-up and survival; (3) prognostic factors analysis of CRC patients undergoing operation; (4) establishment and evaluation of a nomogram prediction model based on CCI. Follow-up was conducted using the telephone interview or outpatient examination to detect the survival of patients up to March 2020. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was analyzed using the t test. Measurement data with skewed distribution were described as M(range) or M( Q1, Q3), and comparison between groups was analyzed using the Mann-Whitney U test. Count data were described as absolute numbers or percentages, and comparison between groups was analyzed using the chi-square test. Non-para-meter rank sum test was used for comparison of ordinal data. The Kaplan‐Meier method was used to calculate survival rates and draw survival curves, and Log-Rank test was used for survival analysis. Univariate and multivariate analyses were performed using the COX proportional hazard regression model. The independent risk factors were included into R4.0.4 software to construct a nomogram prediction model. The receiver operating characteristic (ROC) curve was drawn, and the area under curve (AUC) was used to evaluate discrimination of the nomogram prediction model. The C-index and calibration chart were used to evaluate consistency of the nomogram prediction model. Results:(1) Clinicopathological characteristics of CRC patients undergoing operation. Of the 1 337 patients, there were 1 041 cases with CCI ≤3 and 296 cases with CCI ≥4. Age, cases with non-smoking history, smoking cessation or smoking history, cases without or with R 0 resection, cases with low, moderate, well differentiated tumor, cases in stage Ⅰ?Ⅱ or Ⅲ?Ⅳ of clinical TNM staging, preoperative carcinoembryonic antigen (CEA) were 61(53,68)years, 717, 43, 281, 12, 1 029, 123, 859, 59, 666, 375, 3.22(1.84,7.75)μg/L for the 1 041 patients with CCI ≤3, versus 70(61,75)years, 217, 19, 60, 43, 253, 48, 237, 11, 102, 194, 5.55(2.43,17.64)μg/L for the 296 patients with CCI ≥4, showing significant differences in the above indicators between them ( Z=?10.50, χ2=7.34, 104.51, Z=?2.31, χ2=82.14, Z=?5.78, P<0.05). (2) Follow-up and survival. All the 1 337 patients were followed up for 31(range, 1?84)months. Of the 1 337 patients, 1 024 cases survived and 313 cases died. The 1-, 3-, 5-year survival rates were 94.8%, 85.5%, 80.1% for the 1 041 patients with CCI ≤3, versus 73.6%, 46.9%, 34.0% for the 296 patients with CCI ≥4, showing significant differences between them ( χ2=181.93, P<0.05). (3) Prognostic factors analysis of CRC patients undergoing operation. Results of univariate analysis showed that age, smoking history (having a history of smoking), tumor location (decending colon-sigmoid colon, recto-sigmoid junction-rectum), R 0 resection, tumor differentiation degree (moderate differentiation, well differentiation), clinical TNM staging, postoperative radio-therapy and chemotherapy, preoperational CEA and CCI were related factors for operative prognosis of CRC patients ( odds ratios=1.76, 0.71, 0.72, 0.61, 0.08, 0.39, 0.13, 3.02, 0.60, 2.41, 4.96, 95% confidence intervals as 1.39?2.23, 0.53?0.93, 0.52?0.99, 0.47?0.78, 0.06?0.11, 0.30?0.50, 0.05?0.31, 2.39?3.81, 0.48?0.76, 1.92?3.01, 3.97?6.20, P<0.05). Results of multivariate analysis showed that age >60 years, clinical TNM staging as stage Ⅲ?Ⅳ, preoperational CEA >5 μg/L and CCI ≥4 were independent risk factors for operative prognosis of CRC patients ( odds ratios=1.29, 1.88, 1.77, 2.84, 95% confidence intervals as 1.00?1.65, 1.45?2.44, 1.40?2.23, 2.20?3.67, P<0.05);tumor located in descending colon to sigmoid colon and recto-sigmoid junction to rectum, R 0 resection,tumor differen-tiation degree as moderate and well differentiation, postoperative radiotherapy and chemotherapy were independent protect factors for operative prognosis of CRC patients ( odds ratios=0.71, 0.72, 0.27, 0.50, 0.25, 0.56, 95% confidence intervals as 0.51?0.98, 0.56?0.93, 0.19?0.37, 0.38?0.65, 0.10?0.62, 0.44?0.70, P<0.05) (4) Establishment and evaluation of a nomogram prediction model based on CCI. Based on age, tumor location, R 0 resection, tumor differentiation degree, clinical TNM staging, postoperative radiotherapy and chemotherapy, preoperational CEA and CCI of multivariate analysis results, a nomogram prediction model for operative prognosis of CRC patients was established. The nomogram score was 1.0 for age >60 years, 18.0 for tumor located in proximal colon, 9.0 for tumor located in distal colon, 53.0 for non-R 0 resection, 62.0 for low differentiated tumor, 31.0 for morderate differentiated tumor, 32.0 for stage Ⅲ?Ⅳ of clinical TNM staging, 26.0 for no postoperative radiotherapy and chemotherapy, 4.6 for each increase of 100 μg/L in preoperative CEA and 12.6 for each increase of 1 score in CCI respectively. The total of different scores for risk factors was used to evaluate total 1, 3, 5-year survival rates. The ROC curve was drawn to evaluate the predictive ability for prognosis of nomogram model, with the AUC as 0.75 (95% confidence interval as 0.71?0.79, P<0.05). The C-index was 0.80 (95% confidence interval as 0.77?0.72). The calibration chart showed a good consistency between the probability of survival predicted by nomogram and the actual probability of survival. Conclusions:Age >60 years, stage Ⅲ?Ⅳ of clinical TNM staging, preoperational CEA >5 μg/L and CCI ≥4 are independent risk factors for operative prognosis of CRC patients. Tumor located in descending colon to sigmoid colon and recto-sigmoid junction to rectum, R 0 resection, tumor differentiation degree as moderate and well differentiation, postoperative radiotherapy and chemotherapy are independent protective factors for operative prognosis of CRC patients. The nomogram prediction model contributes to prediction of the survival of CRC patients.

【Objective】 To explore the correlation of preoperative fibrinogen-to-albumin ratio （FAR） with the clinicopathological characteristics and prognosis of patients with rectal cancer so as to clarify the role of coagulation function and nutritional status in the occurrence and progression of tumors. 【Methods】 We retrospectively analyzed the clinicopathological data of 647 patients with rectal cancer who underwent radical resection in The First Affiliated Hospital of Xi’an Jiaotong University from January 1， 2013 to December 31， 2016. According to the optimal cut-off point value of FAR determined by receiver operating characteristic curve， 647 rectal cancer patients were divided into high FAR level group and low FAR level group. The correlation between different preoperative FAR levels and clinicopathological characteristics of rectal cancer patients was analyzed. Multivariate Cox regression analysis was used to analyze the independent risk factors for the prognosis of rectal cancer patients. R software was used to construct the nomogram， and C index and calibration chart were used to evaluate the prediction efficiency of the nomogram. 【Results】 Preoperative FAR levels had a good predictive value for the prognosis of rectal cancer patients. The area under ROC curve was 0.771， the optimal cut-off point was 0.092， and the Youden index was 0.446. There were statistically significant differences in age， T stage， N stage， TNM stage， preoperative CEA levels and preoperative CA19-9 levels between rectal cancer patients with different preoperative FAR levels （P<0.05）. The overrall survival and disease-free survival of rectal cancer patients with different preoperative FAR levels had statistically significant differences （P<0.05）. In the multivariate analysis， preoperative FAR levels （≥0.092， HR=3.298， 95% CI： 2.365―4.600， P<0.001）， age （≥60 years， HR=2.110， 95% CI： 1.479―3.012， P<0.001）， TNM stage （Ⅲ grade， HR=6.743， 95% CI： 2.771―16.771， P<0.001）， grade of differentiation （poor， HR=1.639， 95% CI： 1.104―2.432，P=0.014）， preoperative CA19-9 levels （≥37 U/mL， HR=2.205， 95% CI： 1.529―3.180， P<0.001） and not perform postoperative chemoradiotherapy（HR=1.792， 95% CI： 1.294―2.480，P<0.001） were independent risk factors of overall survival for patients with rectal cancer. OS and DFS nomograms of rectal cancer were established by the Rlanguage software， and the C-index was （0.781， 95% CI： 0.749―0.815； 0.754， 95% CI： 0.693―0.760）， respectively. The calibration curve of the nomogram showed high consistence between predictions and actual results for 1-year， 3-year， 5-year OS and DFS. 【Conclusion】 The preoperative high FAR level was an independent risk factor for the prognosis of patients with rectal cancer. It can be supplemented with pathological factors such as TNM stage as prognostic indicators for patients with rectal cancer， which may be helpful for clinicians to follow up or make beneficial treatment for rectal cancer patients.

Objective:To evaluate the feasibility, safety and efficacy of robotic-assisted lateral lymph node dissection for mid-low advanced rectal cancer.Methods:A retrospective cohort study was performed. Inclusion criteria: (1) age between 18 and 80 years old; (2) rectal adenocarcinoma diagnosed by pathology; (3) without distant metastasis by preoperative CT or MRI; (4) patients underwent robotic-assisted total mesorectal resection (TME). Exclusion criteria: (1) conversion to open surgery; (2) multiple primary tumors; (3) patients underwent combined multiple organ resection. According to the above criteria, 137 patients undergoing robotic-assisted mid-low rectal cancer resection in the First Affiliated Hospital of Xi′an Jiaotong University from December 2016 to April 2019 were enrolled. Ninety-seven cases underwent robotic-assisted total mesorectal excision (TME group) and 40 underwent robotic-assisted total mesorectal resection with lateral lymph node dissection (LLND) (TME+LLND group, pelvic LLND was performed with neurovascular guidance to retain pelvic autonomic nerves in the order of the left side the first and then the right side). The propensity score matching of 1:1 was performed with R software, based on age, sex, BMI, ASA classification, distance from tumor to the anal verge, preoperative chemoradiotherapy history, preoperative abdominal surgery history, the size of tumors and TNM stage. The operative indicators, postoperative recovery, pathology and postoperative complications within 30 days were compared between the two groups.Results:A total of 72 cases were successfully matched (36 in each group), and there were no statistically significant differences in baseline data between the two groups (all P>0.05). The operation time of TME+LLND group was significantly longer than that of TME group [275.0 (180-405) minutes vs. 220.0 (140-320) minutes, Z=-3.680, P<0.001], while there were no statistically significant differences in blood loss during operation, time to postoperative first flatus, postoperative hospital stay, total hospital cost, tumor differentiation, and distal resection length of margin (all P>0.05). Circumferential resection margin was all negative in both groups. The number of harvested lymph modes in the TME+LLND groups was higher than that in the TME group [26 (18-37) vs. 14 (9-36), Z=-6.407, P<0.001]. In addition, there were no statistically significant differences in postoperative morbidity and Clavien-Dindo classification of complication within 30 days between the two groups (both P>0.05). Conclusions:Although robotic lateral lymph node dissection requires longer operation time, it is a feasible, safe and effective procedure.

Objective:To evaluate the feasibility, safety and efficacy of robotic-assisted lateral lymph node dissection for mid-low advanced rectal cancer.Methods:A retrospective cohort study was performed. Inclusion criteria: (1) age between 18 and 80 years old; (2) rectal adenocarcinoma diagnosed by pathology; (3) without distant metastasis by preoperative CT or MRI; (4) patients underwent robotic-assisted total mesorectal resection (TME). Exclusion criteria: (1) conversion to open surgery; (2) multiple primary tumors; (3) patients underwent combined multiple organ resection. According to the above criteria, 137 patients undergoing robotic-assisted mid-low rectal cancer resection in the First Affiliated Hospital of Xi′an Jiaotong University from December 2016 to April 2019 were enrolled. Ninety-seven cases underwent robotic-assisted total mesorectal excision (TME group) and 40 underwent robotic-assisted total mesorectal resection with lateral lymph node dissection (LLND) (TME+LLND group, pelvic LLND was performed with neurovascular guidance to retain pelvic autonomic nerves in the order of the left side the first and then the right side). The propensity score matching of 1:1 was performed with R software, based on age, sex, BMI, ASA classification, distance from tumor to the anal verge, preoperative chemoradiotherapy history, preoperative abdominal surgery history, the size of tumors and TNM stage. The operative indicators, postoperative recovery, pathology and postoperative complications within 30 days were compared between the two groups.Results:A total of 72 cases were successfully matched (36 in each group), and there were no statistically significant differences in baseline data between the two groups (all P>0.05). The operation time of TME+LLND group was significantly longer than that of TME group [275.0 (180-405) minutes vs. 220.0 (140-320) minutes, Z=-3.680, P<0.001], while there were no statistically significant differences in blood loss during operation, time to postoperative first flatus, postoperative hospital stay, total hospital cost, tumor differentiation, and distal resection length of margin (all P>0.05). Circumferential resection margin was all negative in both groups. The number of harvested lymph modes in the TME+LLND groups was higher than that in the TME group [26 (18-37) vs. 14 (9-36), Z=-6.407, P<0.001]. In addition, there were no statistically significant differences in postoperative morbidity and Clavien-Dindo classification of complication within 30 days between the two groups (both P>0.05). Conclusions:Although robotic lateral lymph node dissection requires longer operation time, it is a feasible, safe and effective procedure.

Objective: To evaluate combined robotic and endoscopic surgery in the third space for gastric submucosal tumors(SMTs). Methods: Combined surgery in 4 patients were compared with 19 patients who underwent laparoscopic wedge resection between Aug 2017 and Feb 2018. Results: R₀ resection was achieved in all combined surgery patients. The operation time was longer (112±29 )min vs. (93±11 ) min (t=2.338, P<0.05), but less blood loss, (11±6)ml vs.(59±6)ml (t=15.102, P<0.01). In combined surgery group, there was a larger tumor over resected tissue percentage, 65.4%±28.2% vs.22.8%±19.6% ( t=3.680, P<0.05). Combined surgery group patients were with earlier first breaking wind (3±1.4) d vs.(4.1±0.9) d (t=2.026, P>0.05), and shorter hospital stay (6.5±1.3) d vs.( 8.5±0.6) d (t=4.902, P<0.01), but a little higher hospitalization costs(57 651±10 097)rmb vs.(42 620±5 086)rmb (t=4.508, P<0.01). There were no major postoperative complications occurred in neither groups, nor tumor recurrences after 3-month follow-up. Conclusion Combined robotic and endoscopic surgery in the third space for submucosal gastric tumors is a novel operation with short operation time, less blood loss and good result.