Two-Year Interim Analysis of Conservatively Managed Ovarian Tumors


Key Points

  • The 2-year cumulative incidence of invasive malignancy was 0.4%.
  • Spontaneous resolution was observed in 20.2% of patients.

In an interim analysis of a prospective cohort study (IOTA5) reported in The Lancet Oncology, Froyman et al found that the risk of malignancy and acute complications is low when adnexal masses with benign ultrasound findings are managed conservatively.

In the study, patients with at least 1 adnexal mass who had been selected for surgery or conservative management after ultrasound assessment were consecutively recruited from 36 sites in 14 countries. In the 2-year interim analysis, outcomes were analyzed among patients who were selected for conservative management of an adnexal mass considered to be benign on ultrasound assessment. Conservative management included ultrasound and clinical follow-up at intervals of 3 months and 6 months, and then every 12 months thereafter.

The primary objective was to determine the cumulative incidence of mass complications and malignancy.

Two-Year Outcomes

Between January 2012 and March 2015, 8,519 patients were recruited to the study. Of these, 3,144 (37%) were selected for conservative management; 221 (7%) had no follow-up data and 336 (11%) underwent surgery prior to planned follow-up scan. Among 2,587 patients (82%) with follow-up data, 668 (26%) were already in follow-up at recruitment and 1,919 (74%) presented with a new mass at recruitment.

Median follow-up of the 1,919 patients with new masses at recruitment was 27 months. At 2 years, 20.2% of patients had spontaneous resolution. Overall, 16.1% underwent surgery, with surgical intervention due to suspected malignancy in 2.0%. Findings at surgery consisted of invasive malignancy in 0.4%, borderline tumor in 0.3%, torsion in 0.4%, cyst rupture in 0.2%, minor mass complications in 2.7%, and no mass complications in 12.1%. Death from any cause occurred in 1.2% of patients.

The investigators concluded, “Our results suggest that the risk of malignancy and acute complications is low if adnexal masses with benign ultrasound morphology are managed conservatively, which could be of value when counselling patients, and supports conservative management of adnexal masses classified as benign by use of ultrasound.”

Dirk Timmerman, PhD, of the Department of Development and Regeneration, KU Leuven, is the corresponding author for The Lancet Oncology article.

Disclosure: The study was funded by the Research Foundation Flanders, KU Leuven, and the Swedish Research Council. The study authors' full disclosures can be found at

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