Surgical resection is the only potentially curative therapeutic method for patients with gastric cancer. However, con-ventional laparotomy is sometimes associated with considerable complications and mortality rate. This procedure also affects patient quality of life after surgery. Minimally invasive techniques can potentially provide an attractive alternative to current surgical proce-dures in terms of reducing surgical injury and accelerating postoperative recovery. Minimally invasive surgery for gastric cancer has re-cently been reasonably applied to two distinct forms of intervention:endoscopic resection of the tumor and laparoscopic surgery. In the near future, sentinel node navigation and robot surgery will provide more options for treating gastric cancer. Such developments will im-prove the quality of life of patients following surgery for gastric cancer. Various well-designed clinical trials of the minimally invasive techniques are available. Thus, the mode of surgery for gastric carcinoma will be widely accepted and rapidly developed worldwide.

Objective To explore the feasibility of a novel incisionless laparoscopic technique in the treatment of colorectal tumor, and evaluate the preliminary clinical result of this technique. Methods The clinical data of 12 consecutive resected specimens of high located rectal or sigmoid tumor removed by traditional laparoscopic surgery were analyzed to probe the indication of this technique and the first 2 cases received incisionless laparoscopic anterior resection. Postoperative follow up was made to evaluate the clinical feasibilities. Results Among 12 explanted fresh specimens there were 1 adenoma and 3 adenocarcinoma cases in which the key steps of the new technique were successfully demonstrated. In two cases, the bowel above the tumor was cut and the distal end was inverted and pulled through the anus laparoscopically, the tumor along with the bowel resected, the stump pushed hack, and intralumen sigmoidproctostomy fashioned. In these two patients, one of sigmoid cancer and one of large rectal adenoma with focal canceration, the mean operation time was 200 min, mean blood lose was 50 ml, mean bowel function recovery time was 1.5 days. After 13 and 15 respective months fullow up there was no complications nor tumor recurrence. Conclusions Ineisionless laparoscopic surgery, while in line with tumor free principles, has the advantage of safety, cost-effectiveness and being cosmetic in selected cases.

Objective:To explore the clinicopathological factors in node-negative colon cancer patients with synchronous liver metasta-ses and to improve the efficiency of follow-up and rate of early diagnosis for high-risk patients. Methods:Clinical data of 140 colon cancer patients who underwent operation from January 2008 to December 2012 in Beijing Cancer Hospital were analyzed. The high-risk variables associated with synchronous liver metastases were subjected to univariate and multivariate analyses. Results:Synchro-nous liver metastases developed in 13 out of the 140 node-negative colon cancer patients. Eight out of those 13 patients (61.5%) ex-hibited complications with incomplete colon obstruction, and 6 cases underwent surgical treatment for both primary tumor and liver metastases. Both univariate and multivariate analyses revealed that preoperative abnormal serum carcinoembryonic antigen levels (≥5 ng/mL) and vascular invasion were significant independent risk factors for synchronous liver metastases. Conclusion:The risk of syn-chronous liver metastases for colon cancer patients with negative lymph node is slightly high. Vascular invasion and abnormal preoper-ative CEA levels are significant independent risk factors for synchronous liver metastases. Specific examination of livers is necessary for the special cohort at the time of diagnosis or after operation to avoid misdiagnosis.

Objective To evaluate the clinical value of mini-probe endoscopic ultrasonography (EUS) in determin-ing the therapeutic strategy for early gastric cancer (EGC) before surgery. Methods 151 EGC lesions were enrolled in the study. The accuracy of EUS-determined depths were compared with histopathologic results, and the effects of EUS-based therapeutic decision-making plan was evaluated. Results The overall accuracy of EUS-determined T staging was 74.8%. Multivariate analysis revealed that tumor size larger than 2 cm, endoscopic ulceration and tumor located at upper two thirds of the stomach were associated with EUS misdiagnosis ( < 0.05). 75.3 %(107/142) of the EGC patients received proper treatment according to EUS-based therapeutic selection. Conclusions Mini-probe EUS is a useful utility in T-staging and therapeutic strategy selection for EGC. Special attention should be paid when tumor diameter exceeds 2 cm, co-existence of ulcer or tumor located in the upper two-thirds portion of the stomach.

Objective:To evaluate the clinical outcomes of endoscopic submucosal dissection ( ESD ) for early gastric cancer ( EGC) in a single center in China. Methods:We performed a retrospective ana-lysis of the patients with single EGC lesion who received ESD in Peking University Cancer Hospital from January 2011 to December 2013. Their clinicopathologic data, resectability, curability, complications and follow-up data were assessed. Results:A total of 116 patients were enrolled in the study. The patients in-cluded 88 men and 28 women, with a median age of 63 years ( range:25-80 years) . The post-operative histology of the lesions included 28 (24. 1%) high grade intraepithelial neoplasia, 35 (30. 2%) well differentiated adenocarcinoma, 35 (30. 2%) moderated differentiated adenocarcinoma and 18 (15. 5%) poorly differentiated adenocarcinoma. Of all the lesions, 75. 0% (87/116) were confined into mucosa, 15. 5% (18/116) invaded SM1 ( <500 μm from the muscularis mucosae) and 9. 5% (11/116) inva-ded SM2 (≥500 μm from the muscularis mucosae). The mean tumor size was (1. 49 ± 0. 96) cm, and the rate of ulceration was 14. 7% (17/116). The en bloc resection rates were 96. 7% (111/116), com-plete resection rates were 93. 1% (108/116) and curative resection rates were 77. 6% (90/116). Ac-cording to the curability, 62 (53. 4%) cases were classified into the standard curative resection ( sCR) group, 28 (24. 2%) into the expanded curative resection ( eCR) group and 26 (22. 4%) into thenon-curative resection ( nCR) group. The mean tumor size of the sCR group was smaller than that of the eCR and nCR group (t= -4. 121, P<0. 001 and t= -3. 420, P=0. 001). In the nCR group, the portion of type 0-Ⅲlesion and ulceration were significantly higher (χ2 =10 . 287 , P=0 . 006 andχ2 =17 . 737 , P<0. 001). In multivariate analysis, EGC with ulceration and submucosal invasion were the risk factors for non-curative resection ( OR=6 . 634 , P=0 . 006 and OR=12 . 735 , P<0 . 001 ) . The ESD-related complications included 4 ( 3. 4%) post-operative bleeding, 3 ( 2. 6%) intra-operative perforation, 2 (1. 7%) cardiac stenosis and 1 (0. 9%) heart failure. In the study, 106 of the 116 patients received periodic follow-up, during a median follow-up of 22 months(12 -47 months), Local tumor recurrence developed in 1 patient of the eCR group 8 months post the ESD. Conclusion:ESD is a safe and feasible option for EGC in China, ulceration and submucosal invasion are associated with non-curative resection, and post-operative bleeding and intra-operative perforation should be concerned as the main complica-tions.

Objective To investigate the clinical efficacy of laparoscopy-assisted radical gastrectomy for gastric cancer.Methods The retrospective cohort study was adopted.The clinical data of 210 patients with gastric cancer who underwent laparoscopy-assisted radical gastrectomy at the Peking University Cancer Hospital between May 2009 and December 2012 were collected.Fifty-two,43 and 115 patients were respectively detected in stage Ⅰ,Ⅱ and Ⅲ of postoperative pathological stage.Laparoscopy-assisted radical distal,proximal and total gastrectomies were selectively performed according to the location and extent of tumors.(1) Overall treatment indicators were observed,including surgical procedure,with or without conversion to open surgery,operation time,volumes of intraoperative blood loss and transfusion,number of lymph node dissected,time to anal exsufflation,duration of hospital stay,occurrence of complications,radical degree of tumors of pathological examination.(2) Other indicators were observed,including pathological features of patients in stage Ⅰ,Ⅱ and Ⅲ [gender,age,body mass index (BMI),scores of American Society of Anesthesiologists (ASA),medicinal complication,location of tumors,degree of tumor differentiation and with or without vascular tumor thrombi],intraoperative and postoperative situations (surgical procedure,conversion to open surgery,operation time,volumes of intraoperative blood loss and transfusion,number of lymph node dissected,time to anal exsufflation,duration of hospital stay and radical degree of tumors),postoperative complications,reoperation,death within postoperative day 30 and during follow-up,3-and 5-year survival rates.(3) Evaluation criteria:stages and classification of tumors were evaluated according to the tumor node metastasis (TNM) classification of malignant tumours (Seventh Edition) published by American Joint Committee on Cancer (AJCC) and Union for International Cancer Control (UICC).Severity of complications was evaluated according to Clavien-Dindo classification.Patients were followed up by outpatient examination,telephone interview and correspondence once every half a year up to December 31,2015,abdominal / pelvic CT,chest X-ray and blood test were performed once every half a year within 2 years and once every year within 2-5 years postoperatively,and gastroscopy was performed once every year.Overall survival time was counted from operation date to end of follow-up or time of death.Measurement data with normal distribution were presented as x ± s and comparison between groups was analyzed using the ANOVA.Measurement data with skewed distribution were presented as M (range) and comparison between groups was analyzed using nonparametric test.Comparisons of count data were analyzed using the chisquare test.Survival curve was drawn by the Kaplan-Meier method,and survival analysis was done using the Logrank test.Results (1) Overall treatment:all the 210 patients underwent successful radical gastrectomy,including 100 undergoing distal gastrectomy,35 undergoing proximal gastrectomy and 75 undergoing total gastrectomy.There were 198 patients undergoing radical gastrectomy and 12 patients converted to open surgery.Operation time,volume of intraoperative blood loss,number of patients with blood transfusion and number of lymph node dissected were (258 ± 54) minutes,(103 ± 86) mL,19 and 29 ± 12,respectively.Postoperative recovery:time to anal exsufflation and duration of hospital stay were (3.8 ± 0.9) days and (17 ± 7) days.Fortyfive patients had postoperative complications and 2 were dead within 30 days postoperatively.R0 and R1 resections were respectively applied to 209 and 1 patients.(2) Comparisons among the patients with the different pathological stage:numbers of patients in stage Ⅰ,Ⅱ and Ⅲ were 9,17 and 36 with tumor located in the upper stomach,3,9 and 22 with tumor located in the middle stomach,40,16 and 47 with tumor located in the lower stomach,0,1 and 10 with tumor located in the cross-region stomach,30,23 and 23 in G1 and G2 of tumor differentiation,21,19 and 92 in G3 and G4 of tumor differentiation,7,13 and 69 with vascular tumor thrombi,respectively,with significant differences in above indicators among the patients in stage Ⅰ,Ⅱ and Ⅲ (x2 =25.990,32.928,35.027,P ＜ 0.05).(3) Intra-and post-operative comparisons among the patients with the different pathological stage:numbers of patients in stage Ⅰ,Ⅱ and Ⅲl were respectively 40,20 and 40 with distal gastrectomy,3,8 and 24 with proximal gastrectomy,9,15 and 51 with total gastrectomy,and number of lymph node dissected were 26 ± 9,29 ± 13 and 31 ± 12 in patients with stage Ⅰ,Ⅱ and Ⅲ,showing significant differences in above indicators among the patients in stage Ⅰ,Ⅱ and Ⅲ (x2 =25.730,F =4.336,P ＜ 0.05).(4) Numbers of patients with postoperative overall complications were 11,8 and 26 in stage Ⅰ,Ⅱ and Ⅲ,showing no significant difference (x2 =0.301,P ＞ 0.05).(5) Of 210 patients,203 were followed up for a median time of 43 months (range,1-80 months) with a follow-up rate of 96.67％ (203/210).Sixty-eight patients were dead till the end of follow-up,including 60 died of recurrence of tumor,2 died of surgical complications and 6 died of other causes.Postoperative 3-,5-year overall survival rates were 96.1％,87.8％,62.4％ and 92.9％,77.5％,52.7％ in patients with stage Ⅰ,Ⅱ and Ⅲ,respectively,with a significant difference (x2 =29.071,P ＜ 0.05).Conclusion Laparoscopy-assisted radical gastrectomy for advanced gastric cancer is at least equivalent to early gastric cancer in the safety,with the satisfactory long-term outcomes.

Objective To investigate the safety and efficacy of endoscopic submucosal dissection (ESD) in elderly patients (age ≥ 65 years) with early gastric cancer.Methods The retrospective cohort study was adopted.The clinical data of 145 patients with early gastric cancer who underwent ESD at the Peking University Cancer Hospital between January 2011 and June 2014 were collected.Of 145 patients,57 (age≥65 years) were allocated into the elderly group and 88 (age ＜ 65 years) were allocated into the non-elderly group.ESD was performed to all the patients after the multidisciplinary discussion and evaluation.Observation indicators included operation time,volume of intraoperative blood loss,duration of hospital stay,complications,integrity of resected specimens,negative resection margin,tumor cure and follow-up (survival,tumor recurrence and metastasis).The follow-up using outpatient examination and telephone interview was performed to detect survival of patients and tumor recurrence and metastasis till June 2015.Measurement data with normal distribution were presented as x ± s and comparison between groups was analyzed using t test.Measurement data with skewed distribution were presented as M (range) and comparison between groups was analyzed using nonparametric U test.Count data were analyzed using the chi-square test.Results Operation time,volume of intraoperative blood loss,duration of hospital stay,numbers of patients with postoperative perforation,bleeding,en bloc resection of tumor,piecemeal resection of tumor,negative resection margins,positive resection margins,curative resection,extended curative resection and non-curative resection were 100 minutes (range,20-470 minutes),25 mL (range,5-200 mL),5 days (range,2-10 days),1,2,52,5,50,7,30,17,10 in the elderly group and 110 minutes (range,25-480 minutes),25 mL (range,5-600 mL),4 days (range,2-29 days),3,3,85,3,83,5,47,24,17 in the non-elderly group,respectively,with no significant differences between the 2 groups (U =2 451.000,2 183.500,2 116.500,x2=1.544,1.018,1.210,0.142,P ＞ 0.05).Patients with complications were improved after symptomatic treatment.Of 145 patients,135 were followed up for a median time of 26 months (range,12-53 months).Tumor recurrence rates in the elderly and non-elderly groups were 1.8％ (1/57) and 2.3％ (2/88),showing no significant difference between the 2 groups (x2=0.000,P ＞ 0.05).No tumor recurrence and metastasis and death were occurred in other patients.Conclusion ESD is safe and feasible in the treatment of elderly patients with early gastric cancer,and it is equivalent to short-and long-term efficacies of ESD in non-elderly patients.

Objective: This study aimed to compare the short- and long-term outcomes of laparoscopy-assisted radical gastrectomy between elderly and non-elderly patients with gastric cancer. Methods: A total of 219 patients who underwent laparoscopy-assisted radical gastrectomy in the Department of Gastrointestinal Surgery IV, Peking University Cancer Hospital & Institute from April 2009 to October 2013 were included in this retrospective study. All patients were divided into elderly (≥65 years) and non- elderly (<65 years)groups. We compared these groups based on clinicopathological characteristics, postoperative morbidities, and survival. Results:Theelderly group showed higher ASA scores and higher number of preoperative comorbidities (P<0.05). The operative time, blood loss,and conversion rate did not differ significantly between the groups (all P>0.05). The mean time to first ambulation in elderly group was 2.2±2.3d while first ambulation time in the non-elderly group was 1.4±1.3d,which showed significant difference between the two groups (P<0.05). No significant differences were observed between groups in terms of postoperativemorbidities (34.8％ vs. 28.5％, P> 0.05) as well as 3-year disease-free survival and overall survival (P>0.05). However, the elderly patients withpostoperative morbidities experienced significantly poorer overall survival rate than non-elderly patients (44.5％ vs. 70.5％, P<0.05). Conclusion: Laparoscopy-assisted gastrectomy can be safely and successfully performed in an elderly population with acceptable short- and long-term outcomes.Enhanced perioperative treatment is necessary to improve postoperative outcomes.

Poor experience of teacher-student interaction and low user loyalty exist in MOOC (massive open online courses).Therefore,the campus open online courses (COOC),a network teaching platform,was developed to integrate traditional classroom teaching and network teaching and to build an online-offline curriculum system according to professional training scheme of school.The online-offline teaching design and learning evaluation in COOC platform was also developed.The running data of COOC platform showed that the online-offline learning evaluation model has guiding impact on students' learning attitude because it can record the students' learning process and learning effect,which can enhance students' active participation in self-directed learning.The learning evaluation model in COOC is objective and scientific,which is helpful to improve the quality of teaching and learning.

Objective With the development of laparoscopic surgery technique, the concept of minimally invasive surgery has gradually gained popularity. Laparoscopic minimally invasive technique applied in the treatment of gastric cancer has been recognized by surgeons. In recent years, the indocyanine green labeled near-infrared fluorescence laparoscopic technique has been gradually applied to the surgical treatment of gastric cancer. This technique overcomes the drawbacks of tactile lack of laparoscopic surgery and makes the laparoscopic surgery of gastric cancer more precise and minimally invasive. This article introduces the injection method of indocyanine green and discusses the application of fluorescent laparoscopy in gastric cancer surgery, including intraoperative tumor localization of early gastric cancer, sentinel lymph node biopsy, lymph node navigation of advanced gastric cancer, digestive tract reconstruction and gastrointestinal blood perfusion assessment during the procedure.