The risk of malignancy index (RMI) in ovarian tumors is a validated clinical tool used for risk stratification of ovarian lesions, to guide further management 1-3.
Classification
The score incorporates the patient's menopausal status (M), ultrasound features of the lesion (U), and the serum CA-125 level.
RMI = U x M x CA-125 (U/ml)
U score
- 0 = no features of malignancy on ultrasound
- 1 = one feature of malignancy on ultrasound
- 3 = two or more features of malignancy on ultrasound
Features of malignancy on ultrasound include 1,2:
- irregular solid or multiloculated cystic mass
- solid components on cyst wall
- high Doppler flow in solid components
- ascites, peritoneal nodules, or other evidence of metastases
M score
- 1 = premenopausal
- 3 = postmenopausal
Interpretation
- RMI score greater than 200: high risk, with referral to specialist gynecological cancer service, and staging CT advised
- RMI score 25-200: intermediate risk, with MRI recommended to further evaluate the lesion
- RMI score less than 25: low risk, with repeat clinical assessment advised, with MRI if ultrasound features are borderline 1