ESTIMATED TREATMENT RESPONSES IN METASTATIC COLORECTAL-CARCINOMA BASED ON LONGITUDINAL CARCINOEMBRYONIC ANTIGEN SERIES

Patients presenting with advanced or metastatic colorectal carcinoma w ere randomized to treatment with either 5-Fluoro-Uracil+leucovorin or 5-Fluoro-Uracil+interferon alpha-2-a. Longitudinal series of Carcino-e mbryonic-antigen were obtained and analyzed with a dynamic model in se ven of 16 patients had CEA levels above 10 ng ml(-1). Clinical evaluat ion based on X-ray, ultrasound and CT-scans showed a partial response to the given treatment in three of the seven patients. The dynamic mod el consistinly estimated the maximal accumulated cell kill (approximat ely three logs) in the patients experiencing a clinical response. The remaining four patients with CEA levels above 10 ng ml(-1) showed some reduction in CEA as a consequence of the treatment cycles, although n o clinical response could be established. No response was seen among t he remaining nine patients with CEA levels below 10 ng ml(-1).