Study Of A No Touch Isolation Technique-complete Blocking Technique Applied To Distal Radical Gastrectomy

Objective:(1) To design and construct a no touch isolation technique-complete blocking technique during radical gastrectomy in patients with distal gastric cancer,then consummate the manipulating process of complete blocking techniuqe, achieving the standardization of the operation;(2)To initially evaluate its effect to prevent intraoperative metastases via blood,lymphatics and peritoneum due to surgical manipulation through animal and clinical experiment,then observe whether the technique can improve postoperative long-term survival of patients with gastric cancer and have the value of clinical promotion.Methods:(1)Part One,design of complete blocking technique and animal experiment:a waterproof membrane is firstly applied to cover the serous coat of the tumor after laparotomy,then a cutting stapler is used to block the gastric wall and omentum around the tumor site so that the tumor site was isolated from surgical field and the blocking process is completed thus far;animal experiment:We performed complete blocking technique on8miniature pigs to establish experimental animal models with the former method.Carbon nanoparticles suspension was injected into subserosa at different spots in the blocked area, then lymphatic tracing process was observed,and gastric wall and lymph nodes in and out of blocked region were collected at the end of operation and the microelectric slices(HE) were made and analysed.Meantime,methylthioninium was injected into a catheter inserted in the left gastric artery trunk,then staining conditions in and out of blocked region was observed. Samples of venous blood in and out of blocked region were collected at different time points,then methylthioninium were extracted by SPE and analysed by high performance liquid chromatography(HPLC);(2)Part Two,clinical trials:76patients with distal gastric cancer treated in the Department of Surgery,Huashan hospital,FudanUniversity,from June2009to September2010,were enrolled in the study.They were divided into two groups at random:40were operated on with complete blocking technique in radical gastrectomy as experimental group(blocking group),and36were directly operated on with conventional radical gastrectomy as control group(routine group).All the patients underwent D2lymphadenectomy.Time consumption of operation,length of stay,postoperative complications and other clinical data were recorded and analysed.Besides,samples of portal vein blood and peritoneal washes were obtained before and during tumor resection for both groups. Gastroepiploic vein samples in the blocked region were obtained for experimental group during surgery.The positive expression of CEAmRNA and CK20mRNA were used to detect free cancer cells in these samples with real-time quantitative PCR,and then were compared between groups to analyse whether surgical operation can enhance intraoperative dissemination of cancer cells and whether complete blocking technique can effectively reduce blood and peritoneal metastases during the operation.The authentication method of blocking effect on lymphatic network was same to the animal experiment.All the patients were followed up,then the form and proportion of relapse and metastases as well as disease free survival(DFS)were recorded and compared, to preliminarily evaluate whether distal radical gastrectomy using complete blocking technique can make patients gain clinical benefit.Results:(1)Part One:Complete blocking technique is able to block dissemination of free cancer cells via blood,lymphatics and peritoneum during operation in theory.Animal experiment showed the activated carbon particles flow back along the lymphatics after injected into gastric wall.The lymphatic network in the subserosa was displayed clear,but the carbon particles could not pass through the blocking line.After a while,the lymph nodes in the blocked area were black dyed,but those outside remained normal from beginning to the end of operaion.Results of histologic examination of gastric wall and lymph node were consistent with macroscopic observation.Additionally,after methylthioninium was injected into left gastric artery,the gastric wall outside the blocked area was blue dyed,while in the blocked area was constantly normal.HPLC showed that the concentration of methylthioninium in blood collected from the non-blocked region is several hundred even thousand times higher than the blocked region at all the time points,indicating that complete blocking can prevent methylthioninium penetrating into the blocked area through the feeding artery,nor through the arterial network of gastric wall from non-blocked area.(2)Part Two:except for more time consumption of operation in experimental group due to performance of complete blocking technique,there were no statistical signifcance for the other clinical index(length of stay,postoperaive complications and so on) between two groups. After laparotomy,the positive rate of CEAmRNA and CK20mRNA from portal vein blood samples in experimental group was10%(4/40) and15%(6/40),respectively,for control group,it was8.3%(3/36) and11.1(4/36),there was not statistically significant between two groups(p>0.05);During surgery,when tumor site was touched, CEAmRNA and CK20mRNA expression rate of portal vein blood samples in experimental group was7.5%(3/40) and15%(6/40),respectively,while control groups was30.5%(11/36) and36%(13/36),the difference was statistically significant(p<0.05).As to peritoneal washes samples,there was no statistical signifcance for the two markers’expression rate between experimental group and control group(p>0.05) in the same time.In experimental group,the difference of CEAmRNA and CK20mRNA expression rate in omental venous blood between in and out of the blocked area was statistically significant(p<0.05).Besides,the lymph nodes in the blocked area were fully black dyed but those out of the blocked region were normal,and results of microscopic examination were consistent with gross observation.During the median24months’ follow up, none relapse and died in experimental group,while3patients suffered from relapse and metastases in control group,two of whom had died.Conclusion:(1)Complete blocking technique applied in distal radical gastrectomy can isolate tumor site more overally than before and is qualified for simplicity,convenience and economy in practice,and does not interfere with subsequent operations;miniature pigs(susscrofa) are ideal animal models for imitating epigastric surgery of human being and initially prove that complete blocking technique can cut off blood and lymphatic circulation around stomach.(2)Surgical maneuvers play an important role in increasing the positive molecular detection of CEAmRNA and CK20mRNA in portal vein,indicating operation itself may enhance the incidence of cancer cells disseminating into circulation.Compared to conventional radical gastrectomy, distal radical gastrectomy using complete blocking technique can decrease the positive rate of CEAmRNA and CK20mRNA expression in the blood circulation,and can also block lymphatic flow ideally during surgery,which implies complete blocking technique may effectively prevent free tumor cells being detached from primary tumor into blood and lymphatic circulation due to surgical manipulation,while the effect of reducing peritoneal dissemination is not statistically significant yet.Results of short-term follow-up presented a better prognosis in blocking group compared to the control group,and whether it can improve disease free survival or long term surival rate of patients with distal gastric cancer was under further research and follow-up.