CA 125: a clinically useful tumor marker in the management of colorectal carcinoma metastatic to the liver in patients with normal carcinoembryonic antigen.

Two patients with colon carcinoma metastatic to the liver had normal plasma carcinoembryonic antigen (CEA) levels (<1.0 ng/ml) but elevated CA 125 levels. Treatment of the metastatic disease with chemotherapy, plus surgery in one case, led to declines in the CA 125 levels. These decreases were associated with tumor regression, as confirmed by clinical and radiologic evidence. These findings lead us to conclude that the measurement of CA 125 for patients with normal CEA levels is useful in the management of colorectal carcinoma.