Preoperative serum levels of the carcinoembryonic antigen in hereditary non-polyposis colorectal cancer compared to levels in sporadic colorectal cancer

Background: Carcinoembryonic antigen (CEA) serves as the most widely used and most cost-effective tumor marker in colorectal cancer for almost 30 years. Recent publications about serum CEA levels are based on patient groups without definite differentiation between hereditary and non-hereditary forms of colorectal cancer. Patients and methods: We compared preoperative CEA serum levels from 105 patients with hereditary non-polyposis colorectal cancer (HNPCC) and 107 patients with sporadic colorectal cancer including influences of age and Dukes stage. CEA values in cases of HNPCC were correlated to the findings of microsatellite analyses, mutation analyses of the MMR genes (MLH1, MSH2) and respective immunohistochemistries. Results: Thirty-three HNPCC patients (31%) and 37 patients with sporadic CRC (34%) revealed elevated CEA levels higher than 5 ng/ml. The mean preoperative CEA level in all Dukes stages of HNPCC patients was lower with 31.7 ± 180 ng/ml than in sporadic colorectal cancer with 68.3 ± 424 ng/ml, but without significance (p = 0.72). HNPCC tumors with signs of de-differentiation (G3 and G4) revealed significantly higher CEA values with 62.2 ± 262 ng/ml in comparison to well-differentiated tumors (G1 and G2) with 5.0 ± 9.6 ng/ml (p = 0.02). HNPCC patients with “classical characteristics” (high microsatellite instability (MSI), MMR gene mutation, loss of MMR protein expression) had lower preoperative CEA serum levels than those without equivalent genetic alterations, but without reaching statistical significance. CEA levels of HNPCC tumors increased significantly under occurrence of metastases with mean values of 170.3 ± 343 (p < 0.02). Conclusions: Normal preoperative serum CEA levels do not have the same validity for all colorectal cancer patients. Low CEA levels in HNPCC patients could occur due to well-differentiated tumors and should be considered more critically than in sporadic CRC patients. Further studies including comparison of postoperative CEA development are necessary to elucidate the importance of these results.