Abstract
The serum levels of CA 19-9 and carcinoembryonic antigen (CEA) were determined in 37 patients with benign colorectal diseases and in 111 patients with newly discovered colorectal carcinomas or clinically verified relapses. In cancer patients, the CA 19-9 level ranged from normal (0-37 U ml-1) to 77,500 U ml-1 whereas all samples but one from patients with benign colorectal diseases had a normal value. CA 19-9 was increased in 46% and 45% of patients with an advanced (Dukes C or D) carcinoma or a verified recidive, respectively. Only one out of 26 patients (4%) with a localized (Dukes A or B) carcinoma displayed an elevated CA 19-9 level (greater than 37 U ml-1). No clear correlation was found between the CA 19-9 and CEA levels. The sensitivity of the CA 19-9 test (36%) was poorer than that of the CEA assay (69%), but the new test was markedly more specific (97% vs 70%) than the CEA assay.