The value of serial carcinoembryonic antigen (CEA) in predicting response rate and survival of patients with gastrointestinal cancer treated with chemotherapy.

Elevated serum levels of carcinoembryonic antigen (CEA) were found in 70% of 141 patients with advanced gastrointestinal (GI) cancers. Serial CEA measurements were performed on 70 patients before and during chemotherapy. The majority were treated with 5-FU and Methyl-CCNU (33 patients), 5-FU (19 patients), or 5-FU and mitomycin-C (8 patients). In 49 patients with colorectal carcinoma who had elevated serum CEA prior to chemotherapy, 18 had objective partial tumor remission, 16/18 (89%) showed definite decrease in CEA level, one had no change, and one had an increase CEA titer. Thirty-one patients had either stable disease (10 patients) or increasing disease (21 patients) while on chemotherapy. Of these patients four showed decrease in CEA, eight had no change, and 19 had increase in CEA levels as compared to pretreatment value. The survival of patients with a decrease in CEA during chemotherapy was statistically significant (p = .03) as compared to survival of those with no change or increasing CEA levels. In 21 patients with other GI cancers, the correlation between the clinical response and change in CEA level observed was not as definite as in patients with colorectal carcinoma.