Peritoneal lavage cytology in gastric cancer: An independent predictor of outcome

Background: The prevalence and significance of free cancer cells in the peritoneal cavity of clinically M0 gastric cancer patients is unknown. We reviewed our results with peritoneal washings to determine (1) the prevalence of positive cytology in M0 and M1 disease and (2) the influence of positive cytology on the pattern of failure and survival. Methods: Laparoscopic washings were obtained from 127 patients with gastric cancer at Memorial Sloan-Kettering Cancer Center from December 1, 1990 to August 1, 1996. Cytology was performed by the Papanicolau technique. Results: The prevalence of positive cytology was as follows: 0% (0/45) in T1/T2 M0 disease; 10% (3/31) in T3/T4 M0 disease; and 59% in M1 disease. The three M0 patients with positive cytology recurred intra-abdominally (median follow up of 8.5 months). Survival was significantly less compared with stage-matched controls with negative cytology resected for cure (P <.03), and the same as those patients with stage IV disease. Conclusion: Patients with positive lavage cytology are stage IV, even in the absence of macroscopic peritoneal disease. Laparoscopic lavage cytology is a rapid technique for identifying the subset of M0 patients who are unlikely to benefit from resection alone. Such patients require additional treatment strategies to improve survival.