Risk factor analysis of positive peritoneal cytology in gastric carcinoma

Abstract

Background: Positive peritoneal cytology, despite lack of visible peritoneal metastases, was regarded as an M1 class in the TNM classification (7th edition) in 2010.

Objectives: To analyze factors associated with positive peritoneal cytology and identify groups of patients in whom peritoneal lavage in the diagnostic process could affect therapeutic decisions.

Methods: During the laparotomy, after the opening of the peritoneal cavity, 200 ml of physiological saline at 37°C was administered in the tumor region. After this fluid was mixed and agitated, about 100 mL fluid was recovered from several regions of the abdominal cavity, such as the left subphrenic area, the area between the lesser omentum and the hepatobiliary ligament, and the pouch of Douglas. Immediately after collection, the sample was sent to the Department of Pathology, where the samples were processed by liquid-based cytology technique.

Results. Analysis of the peritoneal fluid for the presence of free cancer cells was done in 52 patients. Positive peritoneal cytology was found in 9 (17.3%) patients. In the group of patients with positive cytology, all patients had T4 tumors, and all were found to have lymph node metastases, while G3 cancer was found in 55.5% of patients. In patients with positive cytology, diffuse gastric cancer, according to Lauren, predominated (7 of 9 patients, 77.7%) , while in patients with negative cytology – intestinal type (41 of 43 patients, 95.3%) . Among the 9 patients with positive peritoneal cytology, 7 (77.7%) patients had tumour located in the lower part, 1 (11.1%) patient had tumour located in the upper part, while the lone patient with diffuse involvement of the stomach was also positive for malignant peritoneal cells.

Conclusions. Based on this study, we can conclude that determinants of positive peritoneal cytology include: tumor stage T4, N+, G3, diffuse histological type, according to Lauren.

Implication: Improvement in the management of patients with gastric cancer.