[Abstract] OBJECTIVE: To investigate the effectiveness of the hemihepatic blood flow complete blockade method to prevent tumor dissemination during hepatectomy. METHODS: The data of 281 hepatocellular carcinoma resection cases meeting the screening criteria from February 2006 to April 2010 were analyzed in a controlled manner. 89 of them used the hemihepatic blood flow complete blocking method to control intraoperative bleeding (group A), while the remaining 192 cases used the Pringle method to control intraoperative bleeding (group B). The rates of intrahepatic recurrence, incidence of pulmonary metastases and overall tumor-free survival at 1, 2 and 3 years after surgery were compared between the two groups. The median tumor-free survival time was 25.9 months in group A and 21.7 months in group B. The overall tumor-free survival rate was significantly higher in group A than in group B (P=0.035). 0.035). Conclusion: Complete hemihepatic flow blockade can effectively reduce the incidence of early pulmonary metastases after hepatectomy and improve patients’ immediate tumor-free survival after surgery, which has positive significance for preventing intraoperative tumor dissemination and improving patients’ prognosis. The application of complete hepatic flow blockade for hepatectomy significantly reduces intraoperative bleeding and liver function impairment. This method completely blocks the unilateral inflow and outflow of hepatic blood as well as the interhemihepatic traffic vessels, completely isolating the hepatocellular carcinoma located in the hepatocellular region, and theoretically reducing the chance of intra- and extra-hepatic dissemination of medical origin during liver cancer surgery. The follow-up data of hepatocellular carcinoma resection under complete hemihepatic flow block from February 2006 to April 2010 in our department were compared with hepatocellular carcinoma resection under hepatic flow block by Pringle method without more than half liver, and the postoperative tumor-free survival and recurrence and extrahepatic metastasis of hepatocellular carcinoma were analyzed and reported as follows. 1. Data and methods 1.1 Case selection criteria (1) single hepatic tumor and confined to one half of the liver; (2) no concomitant carcinoma embolus of sarcoid vessels or bile ducts; (3) regular resection of liver segments, lobes or half of the liver with resection not exceeding half of the liver and no exposed tumor at the incisional margin; (4) complete hepatic flow blocking method or Pringle method; (5) postoperative pathology of hepatocellular carcinoma; (6) (7) no distant metastasis; (8) no death within 30 days after surgery; 1.2 General data From February 2006 to April 2010, there were 281 cases meeting the screening criteria in our department, of which 89 cases (31.7%) were resected by hemihepatic flow complete blocking method (group A) and the remaining 192 cases (68.3%) were resected by Pringle hepatic flow blocking method (group B). All patients in both groups had preoperative liver function of Child-pugh class A. All procedures were performed by the same operator. There was no significant difference between the two groups in terms of general information and hepatectomy style; 1.3 Hepatic flow blocking method (1) Complete hepatic flow blocking method [1]: 2 blocking strips were prepositioned in the posterior hepatic tunnel, one for blocking the traffic vessels between the right and left hepatic halves along the median fissure plane forward around the liver parenchyma, and the other one around the hepatic vein and short hepatic vein on one side to block the hepatic outflow. The Glisson sheath was placed at the transverse sulcus of the hepatoportal to block the inflow of blood into the liver on one side. The blocking sequence was as follows: left and right hemihepatic traffic branch vessels → affected side inflow → affected side outflow; (2) Pringle method: blocking the whole hepatic inflow with latex tubes tied to the hepatoduodenal ligament; 1.4 Statistical methods PASW18.0 software was used for data analysis. Differences in count data were tested by chi-square test, survival rate was calculated by the life table method, and the Wilcoxon (Gehan) test was used to compare the survival rates of the two groups. 2. results 2.1 The postoperative tumor-free survival curves of patients in both groups are shown in Figure 1. the median tumor-free survival time was 25.9 months in group A and 21.7 months in group B. The overall tumor-free survival rate was significantly higher than that in group B (P = 0.035). 2.2 The intrahepatic recurrence rates at 1, 2 and 3 years after surgery were 20.2%, 51.7% and 68.5% in group A and 31.8%, 63.0% and 2.3 The incidence of pulmonary metastases at 1, 2 and 3 years after surgery was 6.7%, 15.7% and 32.6% in group A and 15.1%, 25.0% and 30.7% in group B. Only the incidence of pulmonary metastases at 1 year after surgery was significantly lower in group A than in group B (P=0.048). The rest were not significantly different (P=0.081, 0.755); 2.4 25 cases of pulmonary metastases occurred in both groups within 1 year after surgery, of which 18 cases were multiple, accounting for 72.0%. There were 27 cases of pulmonary metastasis occurred after 1 year postoperatively in both groups, and only 10 cases were multiple, accounting for 37.0%. There was a significant difference between the two (χ2=6.385, P=0.012). 3., Discussion Tumor recurrence and metastasis are the main reasons affecting the efficacy of hepatocellular carcinoma surgery. Recent literature reported that the overall survival rate and tumor-free survival rate of hepatocellular carcinoma at 1, 3 and 5 years after surgery were 78%, 56%, 54.8% and 66%, 55%, 34.8%, respectively. Within 2 years after surgery is a high risk period for recurrence of hepatocellular carcinoma . Tumor size, number, vascular invasion, clonal origin and biological characteristics of the tumor are recognized prognostic factors for postoperative hepatocellular carcinoma. In addition to this, intraoperative compression of the tumor often results in the dissemination of tumor cells in the intra- and extra-hepatic bloodstream, leading to early postoperative recurrence and metastasis. Currently, the anterior approach hepatectomy combined with liver suspension technique has been successfully applied to hemihepatectomy for large hepatocellular carcinoma with extensive adhesions to the diaphragm. This method avoids the shortcomings of traditional large hepatocellular carcinoma resection with limited field exposure, easy to split the tumor leading to hemorrhage, and squeezing the tumor during the liver moving process, which can promote tumor cell dissemination . A multicenter prospective randomized controlled study evaluating whether this method can reduce intraoperative tumor cell dissemination by blood and bone marrow is ongoing and inconclusive. Minimizing compression of the tumor is a tumor-free principle to prevent intraoperative tumor dissemination, but tumors suitable for the anterior approach to hepatic resection are, after all, in the minority, and most require freeing the liver, often increasing the risk of intra- and extra-hepatic tumor metastasis. Besides the common intrahepatic metastasis, lung is the organ most prone to distant metastasis of hepatocellular carcinoma. Therefore, we used the early intrahepatic recurrence rate and the incidence of pulmonary metastasis after hepatectomy to evaluate the effectiveness of the hemihepatic blood flow complete blockade method to prevent intraoperative tumor dissemination. The complete hemihepatic blood flow blocking method isolates the blood pathway of the hemihepatic side of the tumor from the surrounding blood pathway, so that no blood flow passes through the tumor vessels and prevents tumor dissemination caused by shedding tumor cells entering the circulation. The results of the study showed that there was no significant difference between the intrahepatic recurrence rate of hepatocellular carcinoma in group A and group B at 1, 2 and 3 years after surgery. Compared with the rate of intrahepatic recurrence in the early postoperative period, the incidence of pulmonary metastasis could more accurately reflect the intraoperative tumor dissemination. The lower incidence of early intrahepatic metastases in group A suggested that the complete hemihepatic flow blocking method could reduce the intraoperative tumor dissemination through the hepatic vein and early postoperative pulmonary metastases, but whether this flow blocking method could control intraoperative tumor intrahepatic metastases or not. The rate of complete hepatic flow blockade suggests that it can reduce intraoperative tumor dissemination through the hepatic vein to reduce early postoperative pulmonary metastasis. Early lung metastases after hepatectomy are often multiple in both lungs, and our data showed that the proportion of multiple metastases was significantly higher among those who developed lung metastases within 1 year after surgery than those who recurred afterwards (P=0.012). This may be due to the fact that early postoperative lung metastases are mainly caused by the dissemination of a large number of tumor cells due to intraoperative compression of the tumor, while distant lung metastases are mostly caused by the proliferation and expansion of tumor cells due to intrahepatic recurrence of hepatocellular carcinoma. Some studies have shown that in addition to intrahepatic recurrence of hepatocellular carcinoma after surgery, the number of lung metastases is also an independent prognostic factor for hepatocellular carcinoma. Therefore, reducing the incidence of early pulmonary metastases, especially multiple pulmonary metastases, after hepatocellular carcinoma surgery has positive significance in improving the prognosis of patients with hepatocellular carcinoma, and the hemihepatic blood flow complete blockade method does play such a role. The overall tumor-free survival rate in the hemihepatic flow complete blockade group was significantly higher than that in the control group, while the survival curves showed that the tumor-free survival rates in both groups were essentially the same from 3 years after surgery. This indicates that the effect of surgical operation on the long-term postoperative outcome of patients with hepatocellular carcinoma is gradually diminishing and may be more related to the biological characteristics of the tumor itself and the immune status of the patient, while the hemihepatic flow blockade method can improve the tumor-free survival rate in the near future after hepatectomy, i.e., reduce the recurrence and metastasis of tumor in the near future after surgery.