Background Previous studies have suggested that patients with occult peritoneal metastases not seen on preoperative imaging have poor prognosis. In this study, we aim to evaluate the utility and impact of staging laparoscopy and peritoneal cytology in patients with gastric adenocarcinoma. Methods A retrospective analysis of patients with gastric adenocarcinoma managed at two major metropolitan hospitals in Melbourne, Australia, between January 1999 and July 2010 was undertaken. The main outcome measures were the number of patients in whom laparoscopy and/or peritoneal cytology changed treatment intent, and the overall survival of patients with occult metastases detected by laparoscopy/cytology. Results Staging laparoscopy as an independent procedure was performed in 74.3% (148/199) of patients who had neither unequivocal metastases (M1) on preoperative imaging nor early T1 disease on endoscopic ultrasound. Laparoscopy/cytology detected occult metastases in 38 (25.6%) patients (27 macroscopic M1 and 11 microscopic M1 with positive peritoneal cytology only), leading to change in the treatment intent in 37 cases. The median overall survivals of patients with metastatic disease detected at staging laparoscopy (8.3 months, 95% confidence interval (CI) 5.4–16.5) or on peritoneal cytology (4.9 months, 95% CI 4.2–48) were as poor as those with M1 disease seen on preoperative imaging (6.7 months, 95% CI 4.2–8.9), P = 0.97. Conclusions Laparoscopy and peritoneal cytology add incremental value to modern imaging in the staging of gastric adenocarcinomas by detecting occult metastatic disease. Their utility needs to be optimized to allow better treatment selection for gastric cancer patients.
