title: External validation of the adapted Risk of Malignancy Index incorporating tumor size in the preoperative evaluation of adnexal masses.
abstract: OBJECTIVE
  The Risk of Malignancy Index (RMI) is a simple scoring system to standardize and improve the preoperative evaluation of adnexal masses. Since 1990, three versions of the RMI have been validated in different clinical studies. Recently, a fourth version of the RMI (RMI-4) was introduced that includes tumor size as an additional parameter. The aim of this study was to validate the ability of RMI-4 to discriminate between non-invasive lesions and invasive malignant adnexal masses, and to compare its performance with RMI-3.
  
  
  METHODS
  Women scheduled for surgery for an adnexal mass between 2005 and 2009 in 11 hospitals were included. Ultrasonographic characteristics, menopausal status and serum CA 125 level were registered preoperatively, and combined into the RMI. The performances of RMI-3 and RMI-4 were assessed and statistically tested for differences.
  
  
  RESULTS
  A total of 643 patients were included: 469 benign, 73 borderline and 101 malignant tumors. The RMI-3 had a sensitivity of 76%, specificity of 82%, positive and negative predictive values (PPV and NPV) of 45% and 95%, and an accuracy of 81%. The RMI-4 had a sensitivity of 74%, specificity of 79%, PPV of 40%, NPV of 94%, and an accuracy of 78%. The accuracy of RMI-3 was significantly higher than the accuracy of RMI-4 (p=.001). Both models had an area under the curve of 0.86.
  
  
  CONCLUSIONS
  Both RMI-3 and RMI-4 were able to discriminate between non-invasive lesions and invasive malignant adnexal masses, with similar performances. Including tumor size in the RMI does not improve its performance.
authors.affiliation: Radboud University Nijmegen Medical Centre, Department of Obstetrics and Gynecology, Nijmegen, The Netherlands. S.vandenAkker@obgyn.umcn.nl
authors.forename: Petronella A J
authors.initials: PA
authors.lastname: van den Akker
authors.forename: Petra L M
authors.initials: PL
authors.lastname: Zusterzeel
authors.forename: Anette L
authors.initials: AL
authors.lastname: Aalders
authors.forename: Marc P L M
authors.initials: MP
authors.lastname: Snijders
authors.forename: Rahul A K
authors.initials: RA
authors.lastname: Samlal
authors.forename: Jos H A
authors.initials: JH
authors.lastname: Vollebergh
authors.forename: Kirsten B
authors.initials: KB
authors.lastname: Kluivers
authors.forename: Leon F A G
authors.initials: LF
authors.lastname: Massuger
mesh_terms: D000291:Adnexal Diseases / Q000097:blood / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018394:CA-125 Antigen / Q000097:blood; D005260:Female; D005833:Genital Neoplasms, Female / Q000097:blood / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008565:Membrane Proteins / Q000097:blood; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009426:Netherlands; D017698:Postmenopause; D011237:Predictive Value of Tests; D017697:Premenopause; D057234:Preoperative Period; D012189:Retrospective Studies; D012306:Risk; D012680:Sensitivity and Specificity; D047368:Tumor Burden; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D018394:CA-125 Antigen; C451759:MUC16 protein, human; D008565:Membrane Proteins