Evaluation of Peritoneal Lavage for Gastric Cancer Staging in Patients Without Ascites Based on Cytology and Carcinoembryonic Antigen

Background: Imaging, cytological examination of ascites (if present), laparosco- py, and peritoneal lavage are performed before surgery for gastric cancer staging. Peritoneal lavage aims to diagnose the microscopic presence of tumor cells on the peritoneal surface. Positive cytology may have a prognostic value that classifies the disorder as stage IV, in which the patient is no longer an elective surgical candidate. Thus, our study was designed to assess the ability of peritoneal lavage to stage gastric cancer in non-ascitic patients based on cytological evaluation and carcinoembryonic antigen (CEA) level measurement. Methods: In our prospective study, we examined gastric cancer patients who were candidates for elective surgery. Upon entering the abdominal cavity and before tu- mor manipulation, normal saline (500 ml) was applied, and the abdominal cavity was thoroughly dispersed. After three minutes, the fluid was drained and addressed to cytological analysis and CEA measurement by radioimmunoassay (RIA). Study var- iables including age, sex, family history, tumor position, pathology, staging, grading, the original tumor size, regional lymph node involvement, and distant metastases were recorded during the pre- and postoperative staging. The association between positive peritoneal lavage cytology and various patients’ characteristics was investigated. Results: In this study, 94 patients were screened. Due to lymphoma and gastrointes- tinal stromal tumor (GIST), two patients were excluded. We examined 92 patients, including 63 males (68.5 %) and 29 females (31.5 %). The mean age of patients was 58.52 ± 11.87 years. The most common tumor location was the esophagogastric junction. Moderately differentiated adenocarcinoma was the most frequent micro- scopic diagnosis. T3 was the most prevalent primary tumor size in 51 patients. Sev- enty-two patients (78.26%) were operable, of whom 18 (19.6 %) were positive for peritoneal lavage cytology. Positive cytology of peritoneal lavage was significantly related to tumor size, tumor grade, serosa/adjacent organ invasion (T4), laparoscopic staging findings, locally advanced disease (R0), and stage of the disease (P < 0.05). In the peritoneal lavage fluid, elevated CEA titers were significantly related to the high-grade tumor (P = 0.012).  Conclusion: Our study demonstrated that positive cytology and high CEA titers in peritoneal lavage fluid of gastric cancer patients without ascites are significantly correlated to the advanced stages.