IOTA Simple Rules


The Simple Rules are a preoperative classification system for ovarian tumors, consisting of five features typical for benign tumors (“B” features) and five features typical for malignant tumors (“M” features). The Simple Rules can be used to diagnose ovarian cancer in women who have at least one persistent adnexal (ovarian, para-ovarian and tubal) tumor and are considered to require surgery. Based on which of the “B” and “M” features that apply, tumors are classified as Benign, Malignant or Inconclusive:

  • Benign – Only “B” features apply
  • Malignant – Only “M” features apply
  • Inconclusive – no features apply, or both “B” and “M” features apply

The Simple Rules were developed by clinicians and statisticians from the International Ovarian Tumor Analysis (IOTA) group, based on clinical and ultrasound data from 1.066 women recruited at 9 centers in 5 countries (Italy, Belgium, Sweden, France, and UK). All patients included required surgery as judged by a local clinician. All current diagnostic models for adnexal tumors (e.g. IOTA models, RMI, ROMA) have been created for patients undergoing surgery, i.e. patients selected for expectant management were excluded when creating the model.

The manuscript describing the Simple Rules was published in Ultrasound in Obstetrics and Gynecology (Timmerman et al., 2008). The Simple Rules have been successfully validated in several studies.

Please note the Simple Rules cannot replace training and experience in ultrasonography and cannot compensate for poor quality ultrasound equipment. The parameters used in the Simple Rules are based on the terms and definitions as published by the IOTA group.

Online Tool

BIOPROGNOS has implemented ―for training or educational purposes― the last versión of Simples Rules for Ovarian Cancer screening and detection. Use is free of charge and not limited.



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Final Report

Once entered the patient data, our Simple Rules Score Calculator for Ultrasound presents the results as a PDF document, that can be downloaded or sent by email.

Click here to open in PDF format.

The report includes all Patient Data as well as Score, calculated according last version of IOTA Simple Rules.

The Science Behind IOTA Simple Rules

Based on Publications

  1. IOTA 2017 International Ovarian Tumour Analysis. Website
  2. Timmerman, D., Calster, B. D., et al. (2016). Predicting the risk of malignancy in adnexal masses based on the Simple Rules from the International Ovarian Tumor Analysis group. American Journal of Obstetrics & Gynecology. DOI: 10.1016/j.ajog.2016.01.007

Related Publications

  1. Peces Rama, A., Llanos Llanos, M. C., et al. (2015). Simple descriptors and simple rules on the International Ovarian Tumor Analysis (IOTA) Group: a prospective study of combined use for the description of adnexal masses. European Journal of Obstetrics & Gynecology and Reproductive Biology. DOI: 10.1016/j.ejogrb.2015.07.010
  2. Timmerman, D., Testa, A.C., et al. (2008). Simple Ultrasound-based rules for the diagnosis of ovarian cancer. Ultrasound in Obstetrics and Gynecology, 31:681-690. DOI: 10.1002/uog.5365