Introduction/Background To determine which would be the best second step approach for discriminating benign from malignant adnexal masses classified as inconclusive by IOTA Simple Rules (SR).

Methodology Single center prospective study performed (January 2018-Decembre 2021) comprising a consecutive series of patients diagnosed as having an adnexal mass classified as inconclusive according to IOTA SR by non-expert examiners. All women were underwent ROMA analysis, DC-MRI interpreted by an expert radiologist and ultrasound (US) examination by expert gynecological sonologist. Pregnant patients and patients with less than 12 months of follow-up were excluded. Cases were clinically managed according to the result of the US expert examination by either serial follow-up for at least one years or surgery. Reference standard was histology (patient was submitted to surgery if any of the tests was suspicious) or follow-up (Masses with > 12 months and no signs of malignancy were considered as benign). Diagnostic performance of all three approaches were calculated and compared. Direct cost analysis of the test used was also performed.

Results 80 women were included. Seventeen patients were managed expectantly and 63 patients underwent surgery. 23 masses were malignant. Diagnostic performance of all three approaches is shown in table. Both US expert examination and MRI had significantly better diagnostic performance that ROMA. There was no difference in terms of diagnostic performance between US and MRI. Direct costs were significantly lower for US than for MRI and similar to ROMA.

Conclusion US expert examination is the best second step approach in inconclusive adnexal masses as determined by IOTA Simple Rules.