[The value of tumor markers in colorectal cancer]

In 137 patients with colorectal carcinoma carcinoembryonic antigen (CEA) was preoperatively measured in serum. Sensitivity of CEA was dependant on the tumor stage. Patients in early tumor stages (TNM stages I + II) demonstrated only in 10% grossly elevated CEA levels compared with 43% of patients with progressive tumor stages (TNM III + IV). The main importance of tumor markers lies still in postoperative follow-up. In patients with a local recurrence of colorectal carcinoma we measured in 57% CEA levels greater than 10ng/ml, in patients with distant metastases even in 75%. CA 19-9 achieved a lower sensitivity in postoperative follow-up of colorectal carcinoma than CEA. Only 22% of patients with a recurrence of colorectal carcinoma had CA 19-9 levels beyond the normal range (37 U/ml) compared with 67% elevated CEA levels in the same group of patients. CEA is still the most important tumor marker in colorectal carcinoma. Measurement of CA 19-9 in postoperative follow-up is no substitute for CEA, it can only be a supplement.