Prognostic Significance of Preoperative and Postoperative Complement C3 Depletion in Gastric Cancer: A Three-Year Survival Investigation

OBJECTIVES: The role of complement system in predicting prognosis of gastric cancer (GC) remains obscured. This study aims to explore the incidence of complement C3 depletion and associated outcomes in GC patients. METHODS: between August 2013 and December 2013, 106 patients with gastric adenocarcinoma were prospectively analyzed. Plasma levels of complement C3 and C4 were detected at baseline, one day before surgery, and postoperative day 3, respectively. Patients with low C3 levels (<0.75 mg/mL) were considered as having complement depletion (CD), while others with normal C3 levels were included as control. The 3-year overall survival (OS), disease-free survival (DFS), and other outcomes were compared between both groups, with the CD incidence explored meanwhile. RESULTS: The CD incidence was 28.3% before surgery but increased to 37.7% after surgery. Preoperative CD was related to prolonged hospital stay (22.7 versus 19.2 day, P = 0.032) and increased postoperative complications (33.3% versus 14.5%, P = 0.030) and hospital costs (P = 0.013). Besides, postoperative C3 depletion was significantly associated with decreased 3-year OS (P = 0.022) and DFS (P = 0.003). Moreover, postoperative C3 depletion and advanced tumor stage were independent predictive factors of poor prognosis. CONCLUSIONS: Complement C3 depletion occurring in gastric cancer was associated with poor short-term and long-term outcomes.