Froyman W, et al. - As ovarian tumors are usually surgically removed considering the presumed risk of complications, researchers here estimated the cumulative incidence of cyst complications and malignancy during the first 2 years of follow-up after adnexal masses have been classified as benign by use of ultrasonography. Results suggest a low risk of malignancy and acute complications if adnexal masses with benign ultrasound morphology are managed conservatively. This seems to have implication while counseling patients, and supports conservative management of adnexal masses classified as benign by use of ultrasound.

• The international, prospective, cohort International Ovarian Tumor Analysis Phase 5 (IOTA5) study was performed recruiting patients aged 18 years or older with at least one adnexal mass who had been selected for surgery or conservative management after ultrasound assessment from 36 cancer and non-cancer centres in 14 countries.
• At present, follow-up of patients managed conservatively is ongoing.
• Patients who were selected for conservative management of an adnexal mass judged to be benign on ultrasound on the basis of subjective assessment of ultrasound images were analyzed in this 2-year interim analysis.
• Under conservative management, ultrasound and clinical follow-up at intervals of 3 months and 6 months, and then every 12 months thereafter, were included.
• Cumulative incidence of spontaneous resolution of the mass, torsion or cyst rupture, or borderline or invasive malignancy confirmed surgically in patients with a newly diagnosed adnexal mass were the main outcomes of this 2-year interim analysis.

• In IOTA5, 8519 patients were recruited between Jan 1, 2012, and March 1, 2015.
• For inclusion in this analysis, 3144 (37%) patients selected for conservative management were eligible; of these, 221 (7%) had no follow-up data and 336 (11%) were operated on before a planned follow-up scan was done.
• Follow-up data was available for 2587 (82%) patients; of these, 668 (26%) had a mass that was already in follow-up at recruitment, and 1919 (74%) presented with a new mass at recruitment (ie, not already in follow-up in the centre before recruitment).
• Patients with new masses were followed-up for median period of 27 months (IQR 14–38).
• Within 2 years of follow-up among those with a new mass at recruitment (n=1919), the cumulative incidence of spontaneous resolution was 20·2% (95% CI 18·4–22·1), and of finding invasive malignancy at surgery was 0·4% (95% CI 0·1–0·6), 0·3% (<0·1–0·5) for a borderline tumour, 0·4% (0·1–0·7) for torsion, and 0·2% (<0·1–0·4) for cyst rupture.