Serum CA 125 concentrations in patients with benign ovarian tumours

Serum CA 125 concentrations have been measured in 115 patients with histologically confirmed nonmalignant pelvic disease, that is, serous cystadenoma (n = 56), mucinous cystadenoma (n = 14), fibroma (n = 33), thecoma (n = 8), and Brenner tumour (n = 4). Increased CA 125 concentrations (> 35 KU/L) were found in 14 patients, with a range of 46-891 KU/L, a mean of 205 KU/L, and a median of 97 KU/L. The highest values were found in patients with ascites. Serial measurements in one patient showed a fall in the 2 days immediately after surgery, over the next 3 days showing a two- to three-fold increase, followed by a slow return to normal over the next 7 weeks. Elevated CA 125 levels may not indicate ovarian malignancy and do not differentiate between benign and malignant pelvic masses.