Evaluation of metastatic cancer to the eye. Carcinoembryonic antigen and gamma glutamyl transpeptidase.

Plasma carcinoembryonic antigen (CEA) and gamma glutamyl transpeptidase (GTP) were studied in 24 patients with cancer metastatic to the uveal tract. Eighty-three percent demonstrated elevated CEA levels, while only 36% (49 of 135 patients) with primary uveal melanoma showed elevated levels. While none of the uveal melanoma patients had a CEA value greater than 10 ng/ml, 58% (14) of the patients with metastatic tumors to the uvea had values greater than 10 ng/ml. Forty-six percent (11) of patients with metastatic tumors to the uvea demonstrated elevated GTP levels that correlated with documentation of liver metastases. Ninety-two percent of the patients with metastatic cancer to the uvea had either an elevated CEA or GTP level. When used together, plasma CEA and GTP levels appear to be helpful in differentiating metastatic tumors to the uvea from primary uveal melanomas. These assays also appear to be useful in determining tumor burden and concurrent hepatic involvement in patients with metastatic tumors to the uvea.