Risk of malignancy index in ovarian tumors

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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.

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 :

  • 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