The carcinoembryonic antigen and its prognostic impact on immunocytologically detected intraperitoneal colorectal cancer cells.

BACKGROUND: Carcinoembryonic antigen (CEA) has been suggested to promote colon cancer progression. In this study we analyzed the prognostic impact of CEA expression on intraperitoneally detected single colon cancer cells. METHODS: Peritoneal lavage samples of 135 colorectal cancer patients were immunocytologically analyzed, including a staining of cellular CEA; serum CEA levels were measured; and 5-year survival rates were calculated according to immunocytological findings and CEA expression. RESULTS: The worst survival rate of 20% was found in patients suffering from CEA-expressing intraperitoneal tumor cells (P = 0.0006). The prognostic impact of an intraperitoneal tumor cell finding significantly increased when serum CEA levels were elevated: only 23% survived 5 years in contrast to a 85% 5-year survival rate of patients who neither had signs of dissemination nor showed elevated serum CEA values (P = 0.0010). CONCLUSIONS: This study shows that the determination of CEA expression improves the prognostic impact of an intraperitoneal tumor cell finding.