[Application of laparoscopic exploration combined with abdominal exfoliative cytology in the diagnosis and treatment of locally advanced gastric cancer]

Objective: To explore the clinical significance of laparoscopic exploration combined with abdominal exfoliative cytology in the diagnosis and treatment of patients with locally advanced gastric cancer. Methods: Inclusion criteria: (1) cancer confirmed by gastroscopy and pathology without preoperative anti-tumor treatment; (2) no distant metastases found in preoperative imaging examinations; (3) patients without surgical contraindications and being tolerant to surgery; (4) patients were willing to undergo laparoscopic exploration and abdominal exfoliative cytology examination, and signed informed consent. A retrospective cohort study method was used to collect and analyze the clinicopathological data of 225 patients with advanced gastric cancer based on the above inclusion criteria from a prospective, multicenter, open, randomized controlled phase III clinical trial (registration No. NCT01516944) conducted between February 2012 and December 2018 in The Fourth Hospital of Hebei Medical University, including 162 males and 63 females with age ranged from 23 to 78 years old. Forty-five patients (20.0%) were classified as Borrmann type I to II, and 180 (80.0%) were classified as type III to IV. All the patients underwent laparoscopy and peritoneal lavage cytology under general anesthesia. Laparoscopic exploration sequence: left and right diaphragm→liver and spleen→parietal peritoneum→pelvic cavity→greater omentum, small intestine, mesentery→transverse colon mesentery →stomach. Contents of exploration: (1) with or without ascites; (2) whether metastatic lesions existed in the peritoneum, mesentery, omentum and Douglas pouch; (3) whether metastasis existed on the liver surface; (4) whether the gastric lymph nodes were swollen; (5) whether infiltration occurred on the gastric serosa surface; (6) whether gastric wall was stiff. The left and right subphrenic, the abdominal and pelvic peritoneum, and the mesentery were rinsed with 500 ml of sterilized normal saline. Position of the reverse Trendelenburg was used in the Douglas pouch. The peritoneal lavage fluid under the liver and spleen fossa was collected. Cytological examination was carried out for exfoliative tumor cells. Evaluation criteria: (1) peritoneal metastasis (P): P0 meant no peritoneal metastasis, P1 meant peritoneal metastasis; (2) free peritoneal cancer cells (CY): CY0 meant no cancer cells in peritoneal lavage fluid cytology, CY1 meant cancer cells in peritoneal lavage fluid cytology. The results of patients undergoing laparoscopic exploration combined with abdominal exfoliative cytology, treatment options and prognosis were analyzed. Kaplan-Meier method was used to calculate the survival rate and a survival curve was drawn. Log-rank test was used for survival analysis. Results: After laparoscopic exploration in 225 patients, clinical staging was corrected in 68 (30.2%) patients, of whom 7 (3.1%) downstaged and 61 (27.1%) increased in staging. Of 164 patients evaluated as P0CY0 after the first laparoscopy and peritoneal cytology examination, 126 underwent radical D2 surgery, and the other 38 patients were found to have later local lesions or extensive fusion of local lymph nodes, so then received neoadjuvant chemotherapy. Twenty-nine patients evaluated as P1CY0 or P1CY1 and 32 patients as P0CY1 underwent intraperitoneal hyperthermic chemotherapy+conversion therapy, and then a second laparoscopic exploration was performed to determine the treatment plan. In total, the original treatment regimens were changed after laparoscopic exploration in 99(44.0%) cases. The follow-up period ended in January 2019. The overall 2-year survival rate of 225 patients was 64.0%. As for those who were evaluated as P0CY0, P0CY1 and P1CY0-1 after the first laparoscopic exploration, the 2-year overall survival rate was 70.7%, 65.6% and 24.1%, respectively (P=0.002). The stratified analysis showed that among 180 patients with stage III tumor, after laparoscopic exploration combined with abdominal exfoliative cytology, 125 patients were found to be P0CY0, 28 were P0CY1, and 27 were P1CY0-1, whose 2-year overall survival rates were 70.4%, 64.3%, and 29.6% respectively, and the difference among these 3 groups was statistically significant (P=0.009). Conclusion: Laparoscopic exploration combined with abdominal exfoliative cytology in patients with locally advanced gastric cancer has important clinical guiding significance in improving accurate staging, treatment options and prognosis evaluation, and can avoid non-therapeutic open-close abdominal surgery.