O varian cancer is generally detected at an advanced stage and is associated with a 5-year survival rate of about 30%. However, survival rates of greater than 90% have been reported with stage I disease, thus fuelling efforts to determine the role of population screening for the detection of early disease. Recent research has focused on two screening strategies: one using ultrasound alone, the other using the serum tumour marker CA125 for primary screening followed by ultrasound as a second-line test (multimodal screening).Transvaginal or pelvic ultrasonography is used to visualize the adnexae. Benign and malignant tumours are distinguished from one another on the basis of morphology. Complex ovarian cysts with wall abnormalities or solid areas are associated with significant risk for malignant disease, 1,2 whereas unilocular ovarian cysts are associated with a less than 1% risk for ovarian cancer in asymptomatic premenopausal women.3,4 The low specificity of ultrasonography for malignant ovarian lesions, combined with recent findings of a high prevalence of benign ovarian lesions in older asymptomatic women, 5 results in many women requiring further investigations and undergoing potentially unnecessary surgery when ultrasonography alone is used for screening.Serum tumour markers for ovarian cancer exist, of which CA125 has been the most extensively studied. It is expressed by about 80% of epithelial cancers (the most common type of malignant tumour) but has limited specificity when used alone, in that it may also be increased in the presence of other cancers (pancreatic, breast, bladder, liver, lung) as well as benign disease (diverticulitis, leiomyoma, endometriosis, benign ovarian cyst, tubo-ovarian abscess, renal disease) and physiologic conditions (pregnancy and menstruation). Specificity of CA125 screening is improved by the addition of pelvic ultrasonography as a second-line test to assess ovarian lesions (multimodal strategy). The sensitivity of CA125 testing has been further refined by using sophisticated computerized calculations to aid in the interpretation of serial serum levels. 6 Overall, the data from prospective studies of screening for ovarian cancer in the general population 7 suggest that sequential multimodal screening has superior specificity and positive predictive value compared with strategies based on transvaginal ultrasonography alone. However, ultrasonography as a firstline test may offer greater sensitivity for early stage disease.Perhaps the best evidence to date on the use of screening for ovarian cancer comes from a randomized controlled trial of ovarian cancer screening using the multimodal strategy. Although the authors did not find a difference in the number of deaths from ovarian or fallopian cancer in the group that was screened (relative risk 2.0 [95% confidence interval 0.78-5.13]), they did find a significant difference in the median rate of survival in the screened group compared with the control group (72.9 months v. 41.8 months, p = 0.011). 8 Other data from prospective ...
