Is ascites CEA a risk factor for peritoneal carcinomatosis in colorectal cancer?: a long-term follow-up study

Our previous study reported that carcinoembryonic antigen (CEA) levels in peritoneal fluid were significantly correlated with the prevalence of peritoneal carcinomatosis (PC) in colorectal cancer (CRC). The purpose of this study was a long-term follow up of the author's previous study, as well as the identification of correlations with the known risk factors of PC and the comparison of the predictive power of PC in CRC.

A total of 495 patients without PC who underwent CRC operations at St. Mary's Hospital, The Catholic University of Korea, from January 2006 to November 2014 were included in this study. Tumor markers of peritoneal fluid sampled at the beginning of each operation were prospectively analyzed and compared with the known risk factors for PC in CRC.

Multivariate analysis of PC revealed that T4 cancer (OR 5.143, 95% CI 1.400-18.897, p = 0.014), T3 mucinous cancer (OR 17.480, 95% CI 1.577-193.714, p = 0.020), obstructed tumors (OR 6.030, 95% CI 1.627-22.343, p = 0.007), and peritoneal fluid CEA above 5 ng/dl (OR 4.073, 95% CI 1.315-12.615, p = 0.015) were significant risk factors. T4 cancer, obstructed tumors, and peritoneal fluid CEA above 5 ng/dl showed correlations with cancer-free survival. Generally, higher CEA levels in peritoneal fluid were correlated with previously known risk factors for PC in CRC.

Peritoneal fluid CEA has predictive value for PC and prognostic value in CRC. Therefore, we recommend routinely performing ascites CEA analysis in colorectal cancer surgery.