[Specificity of CA 125 tumor marker. A study of 328 cases of internal medicine].

The sensitivity and specificity of CA 125 were evaluated retrospectively in 328 patients, some of them with several diseases, seen between January, 1985 and December, 1986. High levels of CA 125 were found in 110 assays performed in patients with solid tumour (43 cases), peritoneal, pleural or pericardial effusion (39 cases), infection (34 cases), malignant blood disease (3 cases) and various non-malignant and non-infective diseases (45 cases). High CA 125 levels were most frequently observed in patients with effusion. The frequency of cancer increased with the CA 125 titre. CA 125 levels were particularly high in ovarian, peritoneal and uterine carcinomas. It was higher in ovarian cancer than in other types of cancer and further elevated in the presence of effusion, irrespective of the primary cancer. All patients with ovarian carcinoma had ascites. The sensitivity of CA 125 was 59 per cent and its specificity 74 per cent in solid tumours and malignant blood diseases. The corresponding figures in solid tumours alone were 72 per cent and 75 per cent respectively. While there can be no doubt that CA 125 is valuable in the follow-up of patients with ovarian carcinoma, the clinical context and notably the presence of an effusion must be taken into account when asking for a CA 125 assay to evaluate the cause of an inflammatory syndrome or of an alteration of the general condition, since CA 125 levels may be raised in a wide variety of non-malignant diseases, and especially in effusions and infections. In this study, a CA 125 titre higher than 1,000 U/ml was always due to the presence of cancer; lower titres must be interpreted according to the clinical context and sometimes the course of the disease.