OBJECTIVETo investigate the predictive value of serum CA125 in peritoneal metastasis, and to examine the association of CA125 with the prognosis.

METHODSClinical data of 1285 gastric cancer patients admitted to the Qilu Hospital from March 2003 to September 2008 were retrospectively reviewed. The sensitivity, specificity and accuracy of serum CA125 for peritoneal metastasis were analyzed. Clinicopathological characteristics and survival were compared between patients with normal serum CA125 level(≤35 μg/L) and patients with elevated serum CA125 level(>35 μg/L).

RESULTSThe specificity, sensitivity and accuracy of serum CA125 for peritoneal metastasis were 96.0%, 13.8% and 81.2%, respectively. A significantly higher incidence of peritoneal metastasis was observed in the patients with elevated serum CA125 level as compared to those with normal serum CA125 level(43.2% vs. 16.5%). CA125 was an independent predictor of peritoneal metastasis(RR=3.475, 95% CI:2.124-5.685). The 5-year overall survival rate in patients with elevated serum CA125 level was 13.5%, which was significantly lower than that of patients with normal serum CA125 level (49.8%, P<0.01). CA125 was an independent prognostic factor of gastric cancers(HR=2.049, 95%CI:1.355-2.873).

CONCLUSIONSerum CA125 is useful in predicting peritoneal metastasis and prognosis of gastric cancer, which should be used as a routine examination of gastric cancer patients.