Risk factors and a risk scoring system for the prediction of malignancy in ovarian cysts

A retrospective study was carried out on 396 patients who presented with ovarian masses. Sixty five (16%) patients were found to have ovarian malignancy while the rest either had benign ovarian tumours (n = 159), endometriotic cysts (n = 130), physiological cysts (n = 20) or inflammatory masses (n = 7). The relative risk for ovarian malignancy among these patients increased significantly (p < 0.001) after the age of 40 years. The presence of ascites, abdominal distension, urinary complaints and loss of appetite and weight were significant individual risk factors for malignancy. Ultrasound image of a complex cyst is also associated with increased risk of malignancy in an ovarian mass. None of the individual risk factors was discriminatory between a benign and malignant cyst. However, these factors can be combined to form a 20-point risk scoring system. The risk of malignancy in an ovarian cyst increased with increasing scores. In this study, the median scores were 3 for benign cyst, 7 for borderline malignancy and 12 for malignant cysts. Using a total score of 7 as a cut off point, one can detect 75% of malignant cysts with a specificity of 84.1%, a positive predictive value of 47.5% and a negative predictive value of 94.6%. It is concluded that the majority of malignant ovarian cysts can be identified preoperatively to allow arrangement and planning of an optimal surgery.