Clinicopathological analysis and prognostic significance of peritoneal cytology in Chinese patients with advanced gastric cancer

Background: The influence of peritoneal cytology on survival of patients with gastric cancer has not been consistent. This study was to identify risk factors for positive peritoneal cytology and to evaluate the predictive value of positive cytology among Chinese patients with advanced gastric cancer. Methods: The study included 139 patients with gastric cancer macroscopically invading the serosa, who underwent gastrectomy and intra-operative peritoneal cytological examination. In these patients, the relationship between cytological positivity and various clinicopathological features was analysed, and survival analysis was performed to identify independent prognostic factors of significance. Results: Thirty-eight (27.3%) of 139 patients had positive peritoneal cytology. Although tumour size, lymphovascular invasion, depth of tumour invasion, lymph node metastasis and peritoneal metastasis were correlated with positive cytology, multivariate analysis revealed the depth of tumour invasion and peritoneal metastasis as the independent features affecting the cytology. Patients with a positive cytology result were confirmed to have a greater risk for recurrence in the pattern of peritoneal carcinomatosis and a significant inferior prognosis. Multivariate analysis indicated that positive peritoneal cytology was an independent prognostic factor among the curatively resected patients with advanced gastric cancer and was the prognostic factor most predictive of death for these patients (risk ratio = 2.74). Conclusions: Positive peritoneal cytology correlated with advanced features of gastric cancer. It is an independent poor prognostic factor, and it may serve as a guide for adjuvant therapeutic options to improve the survival of gastric cancer.