Factors influencing serum CA125II levels in healthy postmenopausal women.

Our objective was to identify factors that correlate with CA125 concentrations in healthy postmenopausal women and to introduce recommendations for reporting and interpreting individual CA125 assay results. We analyzed repeated serum CA125 levels, as measured by the CA125II assay, in 18,748 postmenopausal women who participated in the ST: Bartholomew's/Royal London Hospital Ovarian Cancer screening trial from 1986 to 1994 and were not diagnosed with ovarian cancer during the 12-year follow-up period. We found that race is a substantial predictor of normal levels of CA125, with average CA125II concentration from African (median, 9.0; 95% range, 4.0-26.0 units/ml) and Asian women (median, 13.0; range, 5.9-33.3 units/ml) lower than that in Caucasian women (median, 14.2; range, 6.0-41.0 units/ml; P < 0.001). Women with a hysterectomy have lower CA125II values (median, 13.6; range 5.5-39.0 units/ml; P < 0.001), and women with a prior cancer diagnosis other than ovarian cancer have higher levels of CA125 II (median, 16.0; range, 6.0-49.0 units/ml; P < 0.003). Regular smoking and caffeine consumption decrease CA125 levels (P < 0.001). A woman's age, age at menarche, age at menopause, and history of a previous ovarian cyst (P < 0.05) are also predictive of baseline CA125 levels. Parity, history of hormone replacement therapy or unilateral oopherectomy, and previous use of oral contraceptives or talcum powder are not significant predictors of CA125 concentrations (P > 0.05). We concluded that clinically significant differences in individual patient characteristics need to be reflected in the screening algorithms that use CA125II so that designed performance characteristics (sensitivity and specificity) are maintained in practice.