Unexpected increase of the CA 19-9 tumour marker in patients with endometriosis

The purpose of this study was to investigate whether the ovarian function o f women with endometriosis could be identified by serologic concentration o f the oncofetal antigen CA 19-9 before, during and after treatment fur 6 mo nths with danazol. A total of 15 women with endometriosis, 20-40 years old, were studied. The serum CA 19-9 antigen was measured by immunoradiometric assay. The measurement of CA 19-9 was repeated during the last 15 days of a 6-month therapy period with danazol and after 3 months from the end of the therapy in only seven women. It was found that: 1) Eight out of 15 women ( 53.3%) showed higher CA 19-9 values than the upper normal limit. 3) Danazol caused a significant decrease in the antigen values which remained stable after the cessation of therapy. This data suggests that endometriosis shoul d be classified among other diseases which cause an increase in the serum l evels of CA 19-9 and that ovarian function is related to antigen levels.