Background: The use of serum tumor markers for the early detection of ovarian cancer has been limited because of their low sensitivity and low positive predictive value. CA 125 levels are elevated in only about one half of women with Stage I ovarian cancer, thus researchers have focused on using the serial measurement of complementary markers to improve the sensitivity, specificity, and positive predictive value of this approach for screening.
Methods: Multiple serum markers have been analyzed in women with early stage epithelial ovarian cancer. CA 125, CA 15-3, C19-9, CA 54-61, CA 72-4, CEA, HMFG2, IL-6, IL-10, LSA, M-CSF, NB70K, OVX1, PLAP, TAG72, TNF, TPA, and UGTF have been studied alone and in combination in this setting. Complementarity and logistic regression analyses have been performed to assess those markers with the highest likelihood of improving sensitivity and specificity for early detection. Serial analysis of a second-generation CA 125 measuring the intercept (initial level) and slope (change of levels over time) can be used to discriminate malignant cases from benign and normal cases.
Results: Analyses have shown that the serial measurement of the new, more sensitive CA 125 has a high sensitivity (83%), specificity (99.7%), and positive predictive value (16%) for the early detection of ovarian cancer. OVX1 used in combination with CA 125 provides the best complementarity. Serial measurements of the two markers have sensitivities in the range of that for transvaginal ultrasonography.
Conclusion: The serial measurement of complementary serum markers can improve the use of marker screening for epithelial ovarian cancer. With the use of several different methods of analysis, it has been shown that this approach improves the sensitivity, specificity, and positive predictive value of serum markers CA 125 and OVX1. A procedure that measures complementary serum markers over time can be used as a primary screening technique followed by transvaginal ultrasonography. This could provide a cost-effective means of early detection and could significantly decrease the probability of surgical intervention for false-positive test results.