title: Comparison of risk of malignancy indices in evaluating ovarian masses in a Southeast Asian population.
abstract: BACKGROUND
  The risk of malignancy index (RMI) is a scoring system used to triage benign from malignant ovarian masses. We compared the specificity and sensitivity of the four indices (RMI 1, RMI 2, RMI 3 and RMI 4) to discriminate a benign ovarian mass from a malignant one in a Southeast Asian population.
  
  
  METHODS
  This was a five-year retrospective study of women who were admitted for surgery due to ovarian masses. RMI scores were calculated based on standardised preoperative cancer antigen (CA)-125 levels, ultrasonography findings, menopausal status and tumour size based on ultrasonography. Postoperative histopathologic diagnosis was regarded as the definite outcome. Data were analysed using the Statistical Package for the Social Sciences, and Mann-Whitney U test was used to compare the individual RMI scores between the benign and malignant cases.
  
  
  RESULTS
  Out of the 480 patients reviewed, 228 women aged 10-65 years were included in the study. Of these, 17 (7.5%) had malignant disease and 211 (92.5%) had benign pathology. There was no statistical difference in the RMI 1, 2, 3 and 4 scores between the benign and malignant cases. Individual variables that were analysed showed significant differences in median CA-125 level and tumour size (p = 0.044 and p < 0.0005, respectively) between the benign and malignant cases.
  
  
  CONCLUSIONS
  Our study shows that RMI is not a valuable triage tool for our Southeast Asian population. Further prospective validation, with regard to standardising results in different patient populations and centres, is required.
authors.affiliation: Department of Obstetrics and Gynaecology, National University Hospital, 5 Lower Kent Ridge Road, Singapore.
authors.forename: Clara
authors.initials: C
authors.lastname: Ong
authors.forename: Arijit
authors.initials: A
authors.lastname: Biswas
authors.forename: Mahesh
authors.initials: M
authors.lastname: Choolani
authors.forename: Jeffrey Jen Hui
authors.initials: JJ
authors.lastname: Low
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D018394:CA-125 Antigen / Q000378:metabolism; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008875:Middle Aged; D015233:Models, Statistical; D010048:Ovarian Cysts / Q000175:diagnosis* / Q000473:pathology; D010051:Ovarian Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012372:ROC Curve; D012189:Retrospective Studies; D012306:Risk; D012680:Sensitivity and Specificity; D012846:Singapore; D055815:Young Adult
chemical_list: D018394:CA-125 Antigen