To evaluate the clinical efficacy of laparoscopic-assisted D2 lymphadenectomy combined with proximal complete mesocolic excision (CME) in the treatment of advanced gastric cancer, and to explore the influence of this combined operation on perioperative clinical outcome, tumor biological behavior and long-term survival and prognosis.

This study was a single-center retrospective cohort study. The samples were 172 patients with advanced gastric cancer admitted to Department of General Surgery, Changzhou Hospital of Traditional Chinese Medicine from January 2022 to December 2023. They were divided into the control group and the observation group based on different surgical methods. The control group underwent laparoscopic D2 radical gastrectomy, while the observation group received laparoscopic D2 radical gastrectomy combined with CME. Surgical-related indices and postoperative recovery were statistically analyzed, and the levels of tumor markers before surgery and 5 days after surgery, as well as postoperative complications were compared between the two groups of patients. All patients were followed up for one year, and the recurrence rate, metastasis rate and survival rate, progression-free survival and overall survival were recorded one year after operation.

Compared with the control group, the operation time of the patients in the observation group was significantly shorter, the blood loss during operation was significantly less, the distance near the incision margin was significantly shorter, and the number of lymph node dissection was significantly more (P<0.05). Compared with the control group, the first exhaust time, the first defecation time and the time of getting out of bed in the observation group were significantly earlier, and the hospitalization time was significantly shorter (P<0.05). The levels of carcino-embryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9) and neuronspecific enolase (NSE) in the two groups decreased significantly after operation compared with those before operation. The levels of tumor markers in the observation group were significantly lower than those in the control group at the same period, and the decrease in the observation group was even greater (P<0.05). There was no statistical difference in the incidence of overall complications between the two groups (P>0.05). The recurrence rate (19.77%) and metastasis rate (8.14%) in the observation group were significantly lower than those in the control group (36.05% and 19.77%) (P<0.05). The survival rate of the observation group (73.26%) was significantly higher than that of the control group (48.84%), and the progression-free survival and overall survival were significantly longer than those of the control group (P<0.05).

Laparoscopic D2 radical resection combined with CME can completely remove the mesangial unit where the tumor is located by following the theory of membrane anatomy, and realize accurate separation of anatomical plane and thorough cleaning of lymphatic drainage system. This operation not only significantly optimizes the perioperative indicators, but also provides a new treatment strategy for advanced gastric cancer with both radical and functional preservation by blocking the potential metastasis pathway in mesangium and remodeling the tumor microenvironment.