title: Triaging women with ovarian masses for surgery: observational diagnostic study to compare RCOG guidelines with an International Ovarian Tumour Analysis (IOTA) group protocol.
abstract: OBJECTIVE
  To compare guidelines from the Royal College of Obstetricians and Gynaecologists (RCOG) based on the Risk of Malignancy Index (RMI) with a protocol based on logistic regression model LR2 developed by the International Ovarian Tumour Analysis (IOTA) group for triaging women with an ovarian mass as low, moderate, or high risk of malignancy.
  
  
  METHODS
  Observational diagnostic study conducted between 2005 and 2007 at 21 oncology referral centres, referral centres for ultrasonography and general hospitals.
  
  
  METHODS
  In all, 1938 women undergoing surgery for an ovarian mass.
  
  
  METHODS
  RCOG guidelines use the RMI to triage women as low (RMI < 25), moderate (25-250), or high (above >250) risk. The IOTA protocol uses LR2s estimated probability of malignancy (<0.05 indicates low risk, ≥ 0.05 but <0.25 moderate risk, and ≥ 0.25 high risk).
  
  
  METHODS
  Percentages of benign, borderline and invasive tumours classified as low, moderate or high risk.
  
  
  RESULTS
  The IOTA and RCOG protocols classified 71.1% and 62.1% of benign tumours as low risk, respectively (difference 9.0; 95% CI 6.2-11.9, P < 0.0001). Of invasive tumours, 88.6% and 73.6% were labelled high risk (difference 15.0; 10.6-19.4, P < 0.0001), and 3.0% and 5.2% were labelled low risk (difference -2.2; -4.6 to 0.2, P = 0.07) respectively by each protocol. Similar results were found after stratification for menopausal status.
  
  
  CONCLUSIONS
  The IOTA protocol was more accurate for triage than the RCOG protocol. The IOTA protocol would avoid major surgery for more women with benign tumours while still appropriately referring more women with an invasive tumour to a gynaecological oncologist.
authors.affiliation: Department of Development and Regeneration, KU Leuven - University of Leuven, Leuven, Belgium. ben.vancalster@med.kuleuven.be
authors.forename: B
authors.initials: B
authors.lastname: Van Calster
authors.forename: D
authors.initials: D
authors.lastname: Timmerman
authors.forename: L
authors.initials: L
authors.lastname: Valentin
authors.forename: A
authors.initials: A
authors.lastname: McIndoe
authors.forename: S
authors.initials: S
authors.lastname: Ghaem-Maghami
authors.forename: A C
authors.initials: AC
authors.lastname: Testa
authors.forename: I
authors.initials: I
authors.lastname: Vergote
authors.forename: T
authors.initials: T
authors.lastname: Bourne
mesh_terms: D000328:Adult; D000368:Aged; D018394:CA-125 Antigen / Q000097:blood; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000175:diagnosis* / Q000601:surgery; D017410:Practice Guidelines as Topic / Q000592:standards*; D018570:Risk Assessment / Q000592:standards; D014218:Triage / Q000592:standards*
chemical_list: D018394:CA-125 Antigen