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

Abstract

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). 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. 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. 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.