Prospective Validation of the ADNEX Model for Discrimination Between Benign and Malignant Adnexal Masses in Pregnancy: International Ovarian Tumour Analysis in Pregnancy Study (p-IOTA)

1\. STUDY SUMMARY TITLE Prospective Validation of the ADNEX Model for discrimination between benign and malignant adnexal masses in pregnancy: the International Ovarian Tumour Analysis in pregnancy study (p-IOTA). DESIGN Multicentre, prospective cohort observational study. BACKGROUND Adnexal masses are a common incidental finding in pregnancy. Whilst the majority are benign and resolve spontaneously, a proportion can exhibit suspicious features during pregnancy raising concern about an underlying malignancy. Correct classification of adnexal masses is particularly important during pregnancy given the potential foetal and maternal risks associated with surgical intervention. International Ovarian Tumour Analysis (IOTA) group have developed robust, ultrasound-based tools, including the ADNEX model to support the classification of adnexal masses. Ultrasound-based tools such the Modified Benign Simple Descriptors and ADNEX have been externally validated to aid in the classification of adnexal masses in non-pregnant women, but their use as a robust diagnostic tool in pregnancy remains to be demonstrated. AIMS The principal objective of this study is to prospectively investigate the ability of the ADNEX Model and a 2-step strategy (i.e. Modified Benign Simple Descriptors followed by ADNEX) to correctly discriminate between benign and malignant adnexal masses diagnosed in pregnancy. PRIMARY OUTCOME MEASURE False discovery rate (number of benign masses / number of masses classified as malignant) when using the ADNEX Model to discriminate between benign and malignant adnexal masses at 11-14 gestational weeks in pregnancy. ELIGIBILITY All women 18 years old and above with an adnexal mass found on ultrasound scan during pregnancy - irrespective of whether the mass known before pregnancy OR diagnosed for the first time on ultrasound scan during pregnancy. DURATION This study will be conducted over a minimum period of three years. KEYWORDS IOTA, ovarian mass, benign, malignant, ultrasound, pregnancy, post-partum