title: A comparative study of the risk of malignancy index and the ovarian crescent sign for the diagnosis of invasive ovarian cancer.
abstract: OBJECTIVE
  To compare the value of the risk of malignancy index (RMI) and the ovarian crescent sign (OCS) in the diagnosis of ovarian malignancy.
  
  
  METHODS
  This was a prospective observational study of women with ultrasonographic diagnosis of an ovarian cyst. The RMI was calculated in all cases using a previously published formula (RMI = U (ultrasound score) x M (menopausal status) x serum CA125 (kU/L)). A value > 200 was considered to be diagnostic of ovarian cancer. The OCS was defined as a rim of visible healthy ovarian tissue in the ipsilateral ovary. Its absence was taken as being diagnostic of invasive cancer.
  
  
  RESULTS
  A total of 106 consecutive women were included in the study, of whom 92 (86.8%) had a benign ovarian tumor, five (4.7%) had borderline lesions and nine (8.5%) had an invasive ovarian cancer. The absence of an OCS diagnosed invasive ovarian cancer with a sensitivity of 100% (95% CI, 70-100%), specificity of 93% (95% CI, 86-96%), positive predictive value (PPV) of 56%, negative predictive value (NPV) of 100% and positive likelihood ratio (LR+) of 13.86 (95% CI, 6.79-28.29). This compared favorably with a sensitivity of 89% (95% CI, 57-98%), specificity of 92% (95% CI, 85-96%), PPV of 50%, NPV of 99% and LR+ of 10.78 (95% CI, 5.34-21.77), which were achieved using RMI > 200 (P < 0.01).
  
  
  CONCLUSIONS
  The RMI and the OCS are useful tests for discriminating between invasive and non-invasive ovarian tumors. The application of these tests in a sequential manner might improve the overall accuracy of ovarian cancer diagnosis.
authors.affiliation: Early Pregnancy and Gynaecology Assessment Unit, King's College Hospital, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Yazbek
authors.forename: N
authors.initials: N
authors.lastname: Aslam
authors.forename: A
authors.initials: A
authors.lastname: Tailor
authors.forename: K
authors.initials: K
authors.lastname: Hillaby
authors.forename: K S
authors.initials: KS
authors.lastname: Raju
authors.forename: D
authors.initials: D
authors.lastname: Jurkovic
mesh_terms: D000465:Algorithms; D018394:CA-125 Antigen / Q000097:blood; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008875:Middle Aged; D010048:Ovarian Cysts / Q000000981:diagnostic imaging / Q000601:surgery; D010051:Ovarian Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D010053:Ovary / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014463:Ultrasonography
chemical_list: D018394:CA-125 Antigen