Depth of tumor invasion and tumor-occupied portions of stomach are predictive factors of intra-abdominal metastasis

OBJECTIVE Diagnostic laparoscopy is recommended for the pretherapeutic staging of gastric cancer to detect any unexpected or unconfirmed intra-abdominal metastasis. The aim of this study was to evaluate the role and indications of diagnostic laparoscopy in the detection of intra-abdominal metastasis. METHODS Standard diagnostic laparoscopy with peritoneal cytology examination was performed prospectively on patients who were clinically diagnosed with primary local advanced gastric cancer (cT≥2M0). We calculated the rate of intra-abdominal metastases identified by diagnostic laparoscopy, and examined the relationship between peritoneal dissemination (P) and cytology results (CY). Split-sample method was applied to find clinical risk factors for intra-abdominal metastasis. Multivariate logistic regression analysis and receiver-operator characteristic (ROC) analysis were performed in training set to find out risk factors of intra-abdominal metastasis, and then validate it in testing set. RESULTS Out of 249 cM0 patients, 51 (20.5%) patients with intra-abdominal metastasis were identified by diagnostic laparoscopy, including 20 (8.0%) P1CY1, 17 (6.8%) P0CY1 and 14 (5.6%) P1CY0 patients. In the training set, multivariate logistic regression analysis and ROC analysis showed that the depth of tumor invasion on computer tomography (CT) scan ≥21 mm and tumor-occupied ≥2 portions of stomach are predictive factors of metastasis. In the testing set, when diagnostic laparoscopy was performed on patients who had one or two of these risk factors, the sensitivity and positive predictive value for detecting intra-abdominal metastasis were 90.0% and 32.1%, respectively. CONCLUSIONS According to our results, depth of tumor invasion and tumor-occupied portions of stomach are predictive factors of intra-abdominal metastasis.