Serum Alkaline Phosphatase Predicts Poor Disease-Free Survival in Patients Receiving Radical Gastrectomy

BACKGROUND: Serum alkaline phosphatase (ALP) has been proved to be a negative prognostic factor for several malignancies, but its clinical significance in gastric cancer (GC) patients has not been sufficiently studied. In the present retrospective study, we investigated the effect of serum ALP on disease-free survival (DFS) after radical gastrectomy. MATERIAL/METHODS: We included 491 GC patients receiving radical gastrectomy at the Chinese People’s Liberation Army 309(th) Hospital. Univariate and multivariate analyses were performed to determine factors influencing serum ALP and DFS. The changes in serum ALP and its clinical relevance were also analyzed using the log-rank test and Cox proportional hazards model. RESULTS: There were 491 patients who met our inclusion and exclusion criteria. Pre-treatment serum ALP was elevated in 87 of these patients and was normal in the other 404 patients. Elevation of pre-treatment serum ALP was correlated with the tumor diameter (OR=2.642, P=0.017), TNM stage (OR=4.592, P=0.005), and T classification (OR=1.746, P=0.043). DFS was significantly different between patients with normal or elevated pre-treatment serum ALP (median 42.1 vs. 32.8 months, P=0.001) and multivariate analysis suggested pre-treatment serum ALP is an independent risk factor for poor DFS after radical gastrectomy (HR=2.035, P=0.021). In addition, removal of the primary tumor lesion led to an obvious decline in serum ALP activity (median 262 U/L vs. 152 U/L, P<0.001), and monitoring changes in serum ALP can help evaluate the risk of tumor relapse in GC patients (χ(2)=17.814, P<0.001). CONCLUSIONS: Serum ALP is a good predictor of GC patient DFS after radical gastrectomy, and patients with elevated serum ALP have shorter relapse times.