Carcinoembryonic antigen (CEA) measurements as an aid to management of patients with lung cancer treated by radiotherapy.

Serial CEA measurements performed in 102 lung cancer patients during and after radiotherapy and chemotherapy correlated well with the course of disease. CEA levels above 10 ng CEA/ml prior to radiotherapy signaled metastatic spread even when this was not evident from clinical staging of the patient (TNM). This finding contributed to the early adoption of radiotherapy in favor of palliative treatment. Alterations of the CEA concentration during therapy could be used for monitoring the efficiency of treatment. Increasing CEA levels always signaled disease progression, decreasing CEA levels were found to be associated with improvement. In the posttreatment follow-up, increasing CEA levels were always reliable predictors of recurrent disease. Slope analysis of the posttreatment CEA time courses discriminated bone and/or liver metastases with a slope greater than 0.5 ng/ml/10 days from local recurrences, lymph node, lung and brain metastases with slope values less than 0.5 ng/ml/10 days.