Prognostic significance of peritoneal washing cytology in patients with gastric cancer

Abstract Background: Positive peritoneal washing cytology is a poor prognostic factor in patients with gastric cancer. The right therapeutic approach for this condition has not been well documented. Methods: Patients who underwent surgery for gastric cancer with suspected serosal invasion and peritoneal washing cytology at the Korean National Cancer Centre between May 2001 and December 2009 were included in this retrospective study. Clinicopathological factors and overall survival were analysed with respect to the cytological results and presence of peritoneal metastases. Prognostic factors were analysed in patients with positive cytology but without overt peritoneal metastases. Results: A total of 1072 patients were included in the analysis, of whom 900 had negative cytology (C0 group) and 172 had positive cytology (C1 group). No peritoneal metastases (P0) were found in 830 patients (92·2 per cent) in the C0 group. Peritoneal metastases (P1) were found in 76 patients (44·2 per cent) in the C1 group. Median overall survival times in the P0 C1, P1 C0 and P1 C1 subgroups were 20·0, 14·0 and 10·0 months respectively. Multivariable analysis of the P0 C1 subgroup revealed that clinical N0–2 category and gastric resection were significantly associated with better prognosis (median survival 24·0 versus 13·0 months for N0–2 versus N3, and 21·0 versus 4·0 months for resected versus non‐resected). Conclusion: Positive washing cytology in patients with gastric cancer is a negative prognostic factor for patients with, as well as those without, overt peritoneal metastases. Resection is an option in patients with clinical stage N0–2 disease without peritoneal metastases but with a positive washing cytology finding. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.