The value of peritoneal cytology as a preoperative predictor in patients with gastric carcinoma undergoing a curative resection

Background: Although positive peritoneal cytology is associated with poor prognosis, it has not been found to be independently predictive of outcome when evaluated in context of post-resection pathologic T and N stage. This study was undertaken to evaluate the predictive value of positive cytology in context of other prognostic factors available prior to surgery in patients undergoing R0 resection for gastric cancer, to assess its role in selecting patients for appropriate treatment prior to surgical resection. Methods: Clinical variables for all patients undergoing R0 resection for gastric adenocarcinoma at Memorial Sloan-Kettering Cancer Center from 1993-2002 were reviewed from a prospective database. Patients underwent preoperative assessment of T and N stage with CT scan, laparoscopy, and endoscopic and/or laparoscopic ultrasound. Peritoneal cytology was obtained in all patients. Results: Patients with gastric cancer (n = 371) underwent R0 resection and staging laparoscopy with peritoneal washings; 24 patients (6.5%) had positive peritoneal cytology. Positive cytology was associated with advanced T stage (P = 0.02) but not with nodal positivity (P = 0.11). Median survival of patients with positive cytology was 14.8 months vs. 98.5 months for patients with negative cytology (P < 0.001). Multivariate analysis identified preoperative T stage, preoperative N stage, site, and cytology as significant predictors of outcome. Positive cytology was the preoperative factor most predictive of death from gastric cancer (RR 2.7, P < 0.001). Conclusions: Positive cytology is information potentially available preoperatively that identifies a patient population at very high risk for early recurrence and death after curative resection of gastric cancer.