Value of Visceral Fat Area in the Preoperative Discrimination of Peritoneal Metastasis from Gastric Cancer in Patients with Different Body Mass Index: A Prospective Study

PURPOSE: Although peritoneal metastasis (PM) is associated with poor prognosis in gastric cancer (GC) patients, it is difficult to discriminate preoperatively. Our previous study has demonstrated visceral fat area (VFA) is a better obesity index than body mass index (BMI) in predicting abdominal metastasis. This study aimed to further explore the relationship between obesity and PM. PATIENTS AND METHODS: VFA was retrieved for 859 consecutive patients undergoing radical gastrectomy between January 1, 2009, and December 31, 2013. A receiver operating characteristic curve analysis was used to determine the BMI-specific cutoff values for VFA. Univariate and multivariate analyses evaluating the risk factors for PM at different BMI levels were performed. RESULTS: The optimal cutoff values for VFA were 67.28, 88.03, and 175.32 cm(2) for low, normal, and high BMI patients, respectively, and 18 (15.52%), 220 (40.15%), and 61 (31.28%) patients were classified as having high VFA in each group. Univariate logistic regression revealed that the association between high VFA and PM was not dependent on BMI (odds ratio [OR]=9.048, P=0.007 for low BMI, OR=3.827, P<0.001 for normal BMI, and OR=2.460, P=0.049 for high BMI). In multivariate logistic regression analysis, high VFA (OR=3.816, P<0.001) and vascular invasion (OR=1.951, P=0.039) were independent risk factors for PM only in the normal BMI group. CONCLUSION: VFA only effectively predicted PM for GC patients with normal BMI, rather than those with low and high BMI. More attentions should be paid to those GC patients with high VFA and normal BMI.