[The relation between serum carcinoembryonic antigen (CEA) and response to chemotherapy in patients with advanced colorectal cancer].

Prognostic factors from 22 cases of advanced colorectal carcinoma were examined with respect to age, the degree of cellular differentiation, pretreatment serum CEA and doubling time of circulating CEA. The prognoses were very poor for patients of younger age and poorly differentiated tumor. No correlations were observed between survival time and pretreatment serum CEA. A significant correlation of survival time and CEA doubling time was observed. The serial serum CEA levels were examined in the 11 colorectal cancer patients with unresectable multiple liver metastasis, who were treated with intraarterial selective chemotherapy. There were no significant differences between pretreatment serum CEA and survival time on response to chemotherapy. In 9 cases showing over 40 ng/ml of CEA before treatment, however, the serial change in CEA levels correlated well with response to chemotherapy. In four cases with recurrent liver metastasis, prolongation time could be predicted from the CEA induces with respect to the forward time earning and the alternation of the CEA doubling time. Furthermore, the two cases without any measurable lesions also showed the same trend. These results suggested that serial measurement of serum CEA were useful for monitoring the response to chemotherapy against advanced colorectal cancer when the pretreatment serum CEA was high (over 40 ng/ml).