Objective To test the accuracy of the risk of malignancy index, the revised risk of malignancy index and Tailor's regression model to diagnose malignancy in women with known adnexal masses.
Design Prospective collaborative study.
Setting Gynaecology Assessment Unit, Department of Obstetrics and Gynaecology, King's College Hospital, London.
Sample Sixty-one women with known adnexal masses were examined pre-operatively. Women were recruited from three South London hospitals.
Methods The demographic, biochemical and sonographic data recorded for each patient included: age; menopausal status; CA125 levels; tumour volume; ultrasound characteristics; and Doppler blood flow analysis (peak and mean blood velocities, the pulsatility and resistance indices). The diagnosis of malignancy was made for each woman using all three models and the results compared with the final histopathological diagnosis.
Results Thirty-eight women had benign tumours and 23 had ovarian cancer. Women with malignant tumours were significantly older than those with benign masses. There were also significant differences in CA125 levels, locularity, presence of papillary proliferations and ascites between the two groups. Tailor's regression model achieved a 43% sensitivity and 92% specificity in the diagnosis of malignancy. This compared with a 74% sensitivity and 92% specificity with the risk of malignancy model, and a 74% sensitivity and 89% specificity with the revised risk of malignancy model.
Conclusion When applied prospectively all three diagnostic models performed less accurately than originally reported, despite clinical signs of malignancy being present in many cases. It is likely that their accuracy would be even less in a population of women in whom there was a substantial clinical uncertainty. Intra-tumoral blood velocity and CA125 levels were the best individual parameters for discrimination between benign and malignant tumours.