A nomogram for estimating the probability of ovarian cancer.
OBJECTIVE
Accurate preoperative estimates of the probability of malignancy in women with adnexal masses are essential for ensuring optimal care. This study presents a new statistical model for combining predictive information and a graphic decision support tool for calculating risk of malignancy.


METHODS
The study included 153 women treated with definitive surgery for adnexal mass between 2001 and 2007 with preoperative ultrasound testing and a serum CA125. Multivariable logistic regression was used to develop a statistical model for estimating the probability of ovarian cancer as a function of age, ultrasound score, and CA125 value, with adjustments for nonlinear and interactive relationships.


RESULTS
A total of 20 cases of pathologically confirmed cancer (13 invasive malignancies, and 7 tumors of low malignant potential) were identified (20/153=13%). The model obtained excellent discrimination (ROC area=0.87), explained nearly half of the observed variation in the risk of malignancy (R²=0.43), and was well calibrated across the full range of malignancy probabilities. The model equation is represented in the form of a nomogram, which can be used to calculate preoperative probability of malignancy. At a 5% risk of malignancy threshold, the model has a sensitivity of 90% and a specificity of 73%.


CONCLUSIONS
Statistical models for estimating the probability of adnexal mass malignancy are substantially improved by including adjustments for non-linear relationships among key variables. A clinically relevant nomogram provides an objective tool to further aid clinicians in counseling patients and ensuring proper referral to surgical sub-specialists when indicated.
Department of Obstetrics/Gynecology, Division of Gynecologic Oncology, University of Virginia Health System, USA.
Jason A
JA
Lachance
Asim F
AF
Choudhri
Marc
M
Sarti
Susan C
SC
Modesitt
Amir A
AA
Jazaeri
George J
GJ
Stukenborg
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D018394:CA-125 Antigen / Q000097:blood; D002648:Child; D005260:Female; D006801:Humans; D016015:Logistic Models; D008565:Membrane Proteins / Q000097:blood; D008875:Middle Aged; D049451:Nomograms; D010051:Ovarian Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000601:surgery; D010052:Ovariectomy; D011336:Probability; D012042:Registries; D014463:Ultrasonography; D014768:Virginia / Q000453:epidemiology; D055815:Young Adult
D018394:CA-125 Antigen; C451759:MUC16 protein, human; D008565:Membrane Proteins