Background: This study was undertaken to assess the correlation between CA125 elevation, a past history of cancer, and future risk of a diagnosis of cancer among asymptomatic postmenopausal women.
Methods: The subjects consisted of a study group of 771 women with elevated CA125 (> or =30 U/mL) and a control group of 771 women with CA125 <30 U/mL. They were selected from a prospective ovarian carcinoma screening trial of 22,000 postmenopausal women followed for a mean of 2269 days.
Results: Subjects in the study group were more likely to have a past history of cancer than subjects in the control group (odds ratio [OR] 2.31, 95% confidence interval [CI] 1.49-3.58). Much of the difference in cancer risk prior to CA125 testing was attributable to a past history of breast carcinoma (OR 2.53, 95% CI 1.45-4.42), but CA125 elevation did not predict recurrence of breast carcinoma. Subjects in the study group were also more likely to develop cancer in the future (OR 2.53, 95% CI 1.61-3.97). This difference was due to an increased risk of gynecologic cancer (OR 30.09, 95% CI 4.09-221.59). CA125 elevation was not associated with an increase in the future risk of developing breast carcinoma (OR 1.19, 95% CI 0.53-2.66) or nongynecologic cancer (OR 1.43, 95% CI 0.86-2.36).
Conclusions: Elevated CA125 in asymptomatic postmenopausal women is not a predictor of nongynecologic cancer or recurrence of cancer, and further investigation should be limited to the detection of gynecologic cancers.