Transabdominal ultrasound screening for early ovarian cancer.

OBJECTIVE: To assess the value of ultrasonography in a screening procedure for early ovarian cancer. DESIGN: Prospective study of at least 5000 self referred women without symptoms of ovarian cancer. Each woman was scheduled to undergo three annual screenings (consisting of one or more scans) to detect grossly abnormal ovaries or non-regressing masses. SETTING: The ovarian screening clinic at King's College Hospital, London. SUBJECTS: 5479 Self referred women without symptoms (aged 18-78, mean age 52). INTERVENTIONS: Women with a positive result on screening were referred for laparoscopy or laparotomy, or both. MAIN OUTCOME MEASURES: Findings at surgery and from histology of abnormal ovaries. RESULTS: A total of 14,594 screenings (15,977 scans) were performed. A positive result was obtained at 338 screens (2.3%) comprising 326 subjects (5.9%). Five patients with primary ovarian cancer (four stage Ia, one stage Ib; two at first screening three at second) were identified (prevalence 0.09%). An additional four patients had metastatic ovarian cancer (three at first screening, one at second). The apparent detection rate was 100%. It was not possible to differentiate between the ultrasonic appearance of early malignant and benign tumours. The rate of false positive results for primary ovarian cancer was 3.5% at the first screening, 1.8% at the second, and 1.2% at the third. Overall the rate of false positive results was 2.3%; the specificity was 97.7% and the predictive value of a positive result on screening was 1.5%. The odds that a positive result on screening indicated the presence of an ovarian tumour, any ovarian cancer, or primary ovarian cancer were about one to two, one to 37, and one to 67 respectively. CONCLUSION: Ultrasonography can be used to screen women without symptoms for persistent ovarian masses that will include early ovarian cancer.