D2 lymphadenectomy can disseminate tumor cells into peritoneal cavity in patients with advanced gastric cancer.

We sought to determine the dissemination of gastric cancer cells before and after radical D2 surgery and to determine the effectiveness of EIPL in preventing post-operative peritoneal metastasis. 64 patients were recruited with advanced gastric cancer for our final analysis. Complete curative gastrectomy with D2 lymphadenectomy was performed on the 64 patients. Before surgery, peritoneal lavage fluid was collected for cytological analysis by cell smearing and immunohistochemistry to detect disseminated cancer cells (S1). Following tumor and lymph node resection, peritoneal lavage fluid was collected for cytological examination (S2). The patients were treated by extensive intra-operative peritoneal lavage (EIPL) with normal saline (n = 31) or distilled water (n = 33). The peritoneal lavage fluid was collected for cytological examination (S3). At S1 stage, 18 patients (28.1%) were positive for disseminated cancer cells in their abdominal fluid. After D2 lymphadenectomy, 34 patients (53.1%) had disseminated cancer cells in their abdominal fluid at stage S2, which indicated that the D2 lymphadenectomy caused in an additional 16 (16/46, 34.8%) patients positive for disseminated cancer cells. After EIPL with either normal saline or distilled water at the S3 stage), all the patients were negative for disseminated cancer cells in their abdominal fluid. A total of six patients died, and four patients had recurrencent cancer. These findings indicate that D2 lymphadenectomy can disseminate gastric cancer cells, and post-operative lavage of the abdominal cavity can eliminate cancer cell dissemination and decrease the risk of peritoneal metastasis.