Serum carbohydrate antigen 125 is a significant prognostic marker in patients with unresectable advanced or recurrent gastric cancer.

PURPOSE: We evaluated the diagnostic and prognostic value of three tumor markers: carcino-embryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and carbohydrate antigen 125 (CA125), in the pretreatment serum of patients with unresectable advanced or recurrent gastric cancer.

METHODS: The subjects of this retrospective analysis were 245 patients with unresectable advanced or recurrent gastric cancer diagnosed at Kochi Medical School between 2007 and 2015. We ascertained the sensitivity of CEA, CA19-9, and CA125 to identify a certain survival time and then evaluated the relative prognosis of the patients.

RESULTS: The overall positive rates for each tumor marker in the study group were as follows: 57.6% (141/245) for CEA, 38.4% (94/245) for CA19-9, and 34.3% (84/245) for CA125; the sensitivity of these three biomarkers in combination was 73.1% (179/245). The median survival time of the CA125-positive patients was 4.5 months, which was significantly shorter than that of a normal range group (18.3 months, P < 0.001). Multivariate survival analysis identified that high CA125 was independently associated with a worse prognosis (HR 3.941; 95% CI 2.544-6.106; P < 0.001).

CONCLUSIONS: Pretreatment serum CA125 is a useful prognostic biomarker in patients with unresectable advanced or recurrent gastric cancer. Evaluating a panel of serum tumor biomarkers is a useful diagnostic tool as elevated values might be associated with poor survival.