Prognostic significance of quantitative carcinoembryonic antigen and cytokeratin 20 mRNA detection in peritoneal washes of gastric cancer patients

Background/Aims: Peritoneal carcinomatosis is the most common recurrence type in gastric cancer. Disseminated tumor cells derived from serosal invasion may be indicators of early peritoneal seeding and subsequent peritoneal dissemination. Reverse-transcriptase polymerase chain reaction (RT-PCR) techniques have been introduced to aid in detection of disseminated tumor cells in peritoneal washes, however, use of a single molecular marker lacks adequate sensitivity. We sought to improve both sensitivity and specificity in detecting disseminated tumor cells in peritoneal washes by using two markers; carcinoembryonic antigen (CEA) and cytokeratin 20 mRNA (CK20 mRNA). Methodology: Between July 2007 and June 2010, peritoneal washing samples were collected from 131 patients who underwent surgery for histologically proven gastric cancer. CEA and CK20 mRNA levels were quantified using a Light Cycler. Results: Analysis using of the two markers had higher sensitivity (93.9%) and specificity (87.7%) than single marker detection (p<0.01, p<0.001 respectively). These analyses also correlated with various clinicopathological factors, and aided in predicting survival and peritoneal recurrence. Conclusions: Two-marker analysis has a significant correlation of survival or peritoneal recurrence in gastric cancer, and this analysis may be more useful as a prognostic predictor of peritoneal recurrence compared with RT-PCR mediated detection of CEA or CK20 alone.