Screening for ovarian cancer.

Ovarian cancer is predominantly a disease of postmenopausal women which presents at a late stage and has an overall 5-year survival of less than 30%. If detected at stage I, survival is dramatically increased and this would suggest that screening for ovarian cancer may reduce mortality. However, the inaccessibility of the ovaries and the absence of a confirmed premalignant condition make screening for preclinical disease difficult. Recent advances in tumour marker interpretation and ultrasound technology have now allowed screening for ovarian cancer to become a real possibility. CA 125 is the most widely used tumour marker for ovarian cancer and it has been shown to be elevated several years before clinical presentation. A new approach to the interpretation of sequential CA 125 results, which uses a mathematical algorithm to determine an individual's risk of cancer, has improved the sensitivity of CA 125 in screening asymptomatic postmenopausal women. Screening using transvaginal ultrasound, Doppler and morphological indices gives encouraging results but, used alone, it currently lacks the specificity required of a screening test for the general population. Multimodal screening using tumour markers and ultrasound in combination gives high sensitivity and specificity and is also the most cost-effective potential screening strategy. The sensitivity and specificity of these techniques are sufficient to warrant large-scale clinical trials of ovarian cancer screening. Three such trials are currently underway and, in due course, will establish whether any screening strategy will ultimately reduce mortality from ovarian cancer.