OBJECTIVE: To evaluate the ability of CA 125, Rrisk of malignancy indices (RMI 1 and RMI 2) to discriminate between benign, borderline or malignant ovarian tumors.

METHODS: This is a retrospective study conducted in tertiary care centre between May 2015 to April 2017. A total of 100 women with adnexal lesions were included in the study. The inclusion criteria included women who underwent surgical intervention and who had preoperative CA–125 testing and pelvic ultrasound in the work–up plan of their management. The surgical intervention was usually followed by a histopathological diagnosis, for  the nature of the lesion, which was used as the gold standard for the evaluation of both CA–125 and RMI. The sensitivity, specificity and positive predictive (PPV) and negative predictive (NPV) values of CA 125 and two RMI were calculated.

RESULTS: This study included 100 women who had serum CA–125 and pelvic ultrasound prior to the surgical intervention of the adnexal lesion. Of these women, 35% had malignant ovarian lesions. Using the proposed cut–off 35 U/ml for CA–125 and 200 for RMI 1 and RMI 2, the CA–125 test was more sensitive for detecting the majority of malignant ovarian tumors compared to the RMI 1 and RMI 2 (73% vs 64% and 67%). However, specificity was better with RMI 1 and RMI 2 than CA 125(98% and 97% vs 95%).Using a cut–off level of 200 to indicate malignancy, the RMI 1 gave sensitivity of 64.7%, specificity of 98.5 %, PPV of 69.2%, and NPV of 98% . The RMI 2 gave sensitivity of 67.6%, specificity of 97.1% %, PPV of 54%, and NPV of 98.3 %. The RMI 2 had better sensitivity in predicting malignancy than RMI 1.

CONCLUSION: Both CA–125 and RMI have good validity in the diagnosis of ovarian tumors.CA–125 has higher sensitivity; however, RMI has higher specificity. RMI 2 is more accurate in discriminating between malignant, borderline and benign ovarian masses. Differential use of these two tools will improve the triage of women with suspected ovarian tumors since both are measured in their work–up.