Objective: To evaluate the diagnostic values of four risk of malignancy indices (RMI) for malignant adnexal masses.
Methods: The data of 223 women with adnexal masses admitted to the Department of Obstetrics and Gynecology of Peking Union Medical College Hospital for surgical exploration between June 2008 and December 2008 were retrospectively analyzed. The sensitivity, specificity, positive predictive value and negative predictive value of RMI1, RMI2, RMI3, and RMI4 in the diagnosis of malignant adnexal masses were calculated.
Results: When the cutoff levels of RMI1, RMI2, RMI3 were set at 200 and RMI4 at 450, the sensitivities for diagnosing malignant adnexal masses ranged 59.0%-67.2%, the specificities ranged 94.4%-96.9 %, the positive predictive values ranged 82.0%-87.8%, and the negative predictive values ranged 90.9%-92.6%. The Youdens indexes (YI) of RMI1, RMI2, RMI3, and RMI4 were 0.559,0.606,0.576, and 0.559, respectively. RMI2 was significantly different from RMI1 (P=0.000), RMI3 (P=0.008), and RMI4 (P=0.000) in terms of diagnostic efficiency. RMI1, RMI2, RMI3, and RMI4 at a cutoff level of 75.688.679.1, 177.2 respectively, according to ROC curves, yielded sensitivities of 77.8%-82.5%, specificities of 84.6%-90.1%, positive predictive values of 69.0%-75.4%, and negative predictive values of 90.9%-92.6%; the relevant YI of RMI1, RMI2, RMI3, and RMI4 were 0.635, 0.665, 0.651 and 0.705, respectively. Under this cutoff level, the difference between RMI1, RMI2, RMI3, and RMI4 in diagnosing malignancy had no statistic significant. The primary histological types arising false negative were early stage epithelial ovarian cancer and non-epithelial ovarian cancer. The primary histological types arising false positive were endometriosis masses and degenerative sex cord-stromal tumor.
Conclusions: RMIs are useful indices for the differentiation between benign and malignant pelvic diseases. Meanwhile, their cutoff levels for Chinese populations need further study.