Thirty-three healthy women (group 1), 20 patients with a history of ovarian carcinoma but no manifest disease at the time of the study (group 2), and 45 patients with surgically demonstrable ovarian cancer (group 3) were studied to establish guidelines for the use of the ovarian cancer antigen Ca 125 in monitoring the course of ovarian carcinoma. Ninety-nine percent of all Ca 125 titers of patients in groups 1 and 2 were less than or equal to 25 U/mL. By contrast, 96% of patients with manifest ovarian cancer had Ca 125 levels greater than 25 U/mL. Ca 125 values rising from the normal range to greater than 25 U/mL predicted recurrent disease in/all of ten patients, provided benign causes (four cases) for titer elevations such as bowel obstruction could be ruled out. Seven of ten patients with recurrent cancer had elevated antigen levels two to five months before the diagnosis could be made clinically. In patients with Ca 125 values greater than 25 U/mL, titer changes of greater than or equal to 50% compared with reference values predicted tumor response or progression in 41 of 43 patients (95%) with antigen positive tumors. Antigen levels less than or equal to 25 U/mL did not exclude the presence of tumor at second look operation in six of 13 patients (46%). It is concluded that the Ca 125 is useful for the detection of persistent and recurrent disease, and for the evaluation of treatment responses. The high false negative rate of 46% in the presence of small amounts of tumor precludes use of the assay in lieu of a second-look operation.
© 1986 The American College of Obstetricians and Gynecologists