Peritoneal cytology in the surgical evaluation of gastric carcinoma

Many patients undergoing surgery for gastric carcinoma will develop periton eal metastases, A method to identify those patients at risk of peritoneal r ecurrence would help in the selection of patients for adjuvant therapy. Per itoneal cytology has received little attention in the West? but may prove a useful additional means of evaluating patients with gastric cancer, The ai ms of this study were to evaluate sampling techniques for peritoneal cytolo gy in patients with gastric cancer, to assess the prognostic significance o f free peritoneal malignant cells and to discover the effect of the operati ve procedure on dissemination of malignant cells. The study is based on 85 consecutive patients undergoing surgical treatment of gastric cancer and fo llowed up for 2 years or until death. Peritoneal cytology samples were coll ected at laparoscopy, and at operation prior to resection by intraperitonea l lavage and serosal brushings. After resection, samples were taken by peri toneal lavage, imprint cytology of the resected specimen and post-operative ly by peritoneal irrigation via a percutaneous catheter. Malignant cells we re diagnosed by two independent microscopists. Preoperative peritoneal lava ge yielded malignant cells in 16 out of 85 cases (19%). The yield of free m alignant cells was increased by using serosal brushings (by four cases) and imprint cytology (by two cases); all of the cases had evidence of serosal penetration. One serosa-negative case exhibited positive cytology in the po st-resection peritoneal specimen in which the preresection cytology specime n was negative. Survival was worse in the cytology-positive group (chi(2) = 25.1; P < 0.0001). Among serosa-positive patients, survival was significan tly reduced if cytology was positive, if cases yielded by brushings and imp rint cytology were included (log-rank test = 8.44; 1 df, P = 0.004). In con clusion, free peritoneal malignant cells can be identified in patients with gastric cancer who have a poor prognosis; the yield can be increased with brushings and imprint cytology in addition to conventional peritoneal lavag e. Evaluation of peritoneal cytology by these methods may have a role in th e selection of patients with the poorest prognosis who may benefit most fro m adjuvant therapy.