Value of serial carcinoembryonic antigen levels in evaluating the response to chemotherapy in patients with advanced digestive cancers.

The main objective of this study was to evaluate the correlation between the carcinoembryonic antigen (CEA) and clinical response to chemotherapy. Sixty-five patients with gastrointestinal cancers treated by chemotherapy were studied. All patients had serial measurements of CEA and an evaluation of tumour response by CT scan. Responses based on CEA were defined in the same way as WHO clinical response based on CT scan. The sensitivity and specificity of CEA was respectively 85% and 90% for objective response, 52% and 76% for stable disease, 71% and 80% for progression. Among 19 patients in stable disease with stable or progressive evolution of their CEA level, 14 (74%) were in progression at a second evaluation, after 2 or 3 more courses of the same chemotherapy. The monitoring of chemotherapy by CEA in patients with metastatic gastrointestinal cancers could be helpful for patients stable at the first evaluation by CT scan or patients with non-measurable disease and having an elevated baseline level of CEA.