Decline of serum CA724 as a probable predictive factor for tumor response during chemotherapy of advanced gastric carcinoma.

OBJECTIVE To evaluate the predictive value of decline in the serum level of carbohydrate antigen 724 (CA724) on tumor response during the chemotherapy in patients with advanced gastric carcinoma (GC). METHODS The serum CA724 level was determined by electrochemiluminescence immunoassay, while the objective response rate (ORR) was assessed according to response evaluation criteria in solid tumors (RECIST). The association of the changes of serum concentration of CA724 with ORR was analyzed. RESULTS The ORR in CA724 (pretreatment serum level) high and low groups was 32.3% (20/62) and 52.8% (19/36), respectively (P=0.045). The relationship between the reduction of CA724 and the ORR was statistically significant (P=0.044). Receiver operating characteristic (ROC) curve established the best cutoff value of the decrease ratio of CA724 as 20.5%. CONCLUSIONS CA724 decline seems to indicate chemotherapy efficacy in patients with advanced GC, and an average drop of 20.5% in serum CA724 appears to predict the sensitivity to chemotherapy.