Carcinoembryonic antigen: Clinical correlation with chemotherapy for metastatic gastrointestinal cancer

Abstract

Serial carcinoembryonic antigen (CEA) titers were measured in 38 patients receiving chemotherapy for metastatic carcinoma of the colon, pancreas, and stomach. CEA levels were initially elevated (over 2.5 ng/ml) in 26 patients (12/20 colonic, 8/10 pancreatic, 6/8 gastric). Seventeen patients had rising serial CEA values during therapy; 13 had evidence of tumor progression, 3 had stable disease, and 1 had no measurable disease. Nineteen patients had stable CEA levels which were either persistently elevated (11 patients) or normal (8 patients). Ten of 11 patients with elevated CEA levels developed tumor progression. In 8 patients with consistently normal CEA levels, 6 (colon) had no evidence of progressive tumor, and 2 (1 pancreatic and 1 gastric) eventually died of metastatic disease. CEA levels decreased in 2 patients with colon carcinoma during remission from chemotherapy. A rising CEA titer often presages clinical deterioration, although elevated CEA levels may remain stable despite progressive disease. Persistently normal CEA, however, is a favorable prognostic sign. The limited effectiveness of chemotherapy for gastrointestinal cancer in this series precludes any definitive conclusion regarding the effect of chemother-apeutically induced tumor regression on CEA levels, although there is suggestive evidence that CEA correlates with remission.