Does Leptin Cause Proximal Gastric Cancer in the Obese? The role of Serum Leptin in the Etiology of Proximal Gastric Cancer

Background: The aim of the present study was to determine the correlation between obesity, serum levels of leptin and proximal gastric cancer. Methods: Sixty-four gastric cancer patients operated on with curative intent were included in the study. We determined the correlation between the preoperative serum levels of leptin and the tumor`s location. Results: Serum leptin levels were correlated significantly with the proximal third location (p = 0.04), gastric outlet obstructing tumors (p < 0.0001), CRP levels (p = 0.03) and BMI (p < 0.0001). Patients with high serum levels of leptin had significantly more intestinal types of gastric cancer (p = 0.033) and better differentiation compared to patients with low serum leptin levels (p = 0.009). The linear regression model determined the proximal tumor location (beta: 0.467; p = 0.045), BMI (beta: 0.657; p = 0.001), high preoperative serum albumin (beta: 0.563; p = 0.016) and the presence of pyloric stenosis (beta: 0.525; p = 0.006) as related significantly to serum leptin levels. The Cox proportional hazard model identified age (HR: 0.003; 95%CI: 0-0.794; p = 0.041), preoperative serum levels of leptin (HR: 0.125; 95%CI: 0.018-0.887; p = 0.037) and the number of extracted LNs (HR: 0.001; 95%CI: 0-0.677; p = 0.038) as independent prognostic factors. Conclusions: Serum levels of leptin were significantly elevated in patients with proximal gastric cancer, suggesting that the leptin`s effect might be due to its systemic secretion. This might explain the higher incidence of proximal gastric cancer in obese patients. Elevated serum leptin levels were an independent prognostic factor.