The adnexal mass: benign or malignant? Evaluation of a risk of malignancy index

Objective To validate a risk of malignancy index incorporating menopausal status, serum CA 125 level and pelvic ultrasound features in the pre-operative diagnosis of ovarian cancer. Design A retrospective observational study. Setting Department of Obstetrics and Gynaecology, The Royal London Hospital. Subjects One hundred and twenty-four women admitted consecutively to the gynaecology department for surgical exploration of an adnexal mass. Main outcome measures The sensitivities and specificities of menopausal status, serum CA 125 level and ultrasound features, in isolation and combined (the risk of malignancy index (RMI)), for diagnosing ovarian cancer. Results Tested on a new population of women, the RMI retained the high sensitivity for diagnosing ovarian cancer seen in the original report describing its derivation. The specificity, however, was lower. The study confirmed that the RMI is more accurate than the individual criteria in diagnosing ovarian cancer, and was comparable with other scoring systems. Conclusions The risk of malignancy index is a simple scoring system for ovarian cancer. Application of the risk of malignancy index in clinical practice may provide a rational basis for specialist referral of patients with ovarian cancer before diagnostic surgery. © 1993.