Authors' objectives:

To evaluate the performance of current screening tests for ovarian cancer.

To assess the adverse effects of screening, including morbidity associated with surgical intervention and psychological morbidity associated with false-positive diagnosis.

To report on the stage of development of newer methods of screening.

To investigate the potential cost-effectiveness of screening in different risk groups.

Authors' results and conclusions: The effectiveness of screening Although three large RCTs are in progress, no RCTs of screening for ovarian cancer have been completed. In the absence of evidence of effectiveness, it would be premature to establish any kind of screening programme. Screening test performance The evidence suggests that both CA 125-based screening and ultrasound screening can detect a higher proportion of ovarian cancers at Stage I than that currently observed in the UK. About 50% (95% CI; 23-77) are diagnosed at Stage I in CA 125-based screening studies, and about 75% (95% CI; 35-97) in ultrasound screening studies. These data should be interpreted cautiously, however, as they are based on small numbers of cancers detected in diverse studies carried out mainly on self-selected women. From the limited data available, annual screening with ultrasound appears to have a sensitivity or detection rate close to 100%. The reported sensitivity of annual CA 125-based screening is about 80%. The precision of these estimates is low, however, as they are based on small numbers of cancers. The false-positive result rate is about 1.2-2.5% for women screened by ultrasound scanning and 0.1-0.6%. for CA 125-based screening. About 0.5-1% of women will suffer a significant complication due to surgery and most of those who do not have ovarian cancer will have a benign gynaecological condition. There is a risk that detection of benign and borderline tumours may become a target of ovarian screening, even though they would not have been associated with any morbidity during a patient's lifetime. Intervals for ultrasound scanning of between 1 year and 3 years are under investigation in the RCTs. CA 125-based screening has been carried out annually. The effect of different screening intervals on the detection rate and false-positive rate has not been formally investigated. About 3-12% of screened women are recalled for further testing and assessment, resulting in potential distress and anxiety to otherwise healthy women. The potential impact of screening for ovarian cancer The low positive predictive value of ovarian screening (3% for surgery and 0.6% for initial recall for annual ultrasound screening; 15% for surgery and 1% for initial recall for annual CA 125-based screening) is due mainly to the relatively low prevalence of ovarian cancer, which limits the potential cost-effectiveness of general population screening. Evidence suggests that ultrasound screening is more sensitive than CA 125-based screening but that the latter may result in fewer false-positives and, hence, a higher positive predictive value. However, a less sensitive test must be repeated more frequently to achieve the same overall detection rate of ovarian cancers, which may reduce the apparent advantages of CA 125-based screening. The most efficient screening method and interval is unknown, but modelling studies suggest that annual CA 125-based screening may provide lower overall benefits but be more cost-effective at detecting early stage cancers than annual ultrasound screening. It is suggested that the addition of colour Doppler imaging (CDI) to ultrasound screening may reduce the false-positive rate but reported results are mixed. Screening a higher-risk population A family history of ovarian cancer is one of the strongest risk factors for developing the disease and some UK centres currently offer screening to women with a strong family history. Until RCTs have been completed, there is no evidence as to whether, or by how much, screening women at higher risk reduces mortality. For some women with an extensive family history of ovarian and/or certain other cancers, the increased risk is associated with an inherited genetic mutation. Carriers of some specific mutations may have a lifetime risk of developing ovarian cancer as high as 50-60%. The identification of some of these mutations raises the possibility of testing individuals in these families to determine whether they are carriers, potentially enabling more accurate assessment of risk.

Authors' recommendations: Further evidence is required before a decision can be made about the potential benefits, harms and costs of screening for ovarian cancer. While awaiting the results of the current trials, demand for screening is likely to increase, and a strong national lead will be required. The relatively low prevalence of ovarian cancer means that the positive predictive value of screening tests is low. Since the consequence of a false-positive result is a surgical procedure, consideration of the overall impact of ovarian cancer screening is important. The low prevalence also limits the potential cost-effectiveness of population screening. Screening women who are at risk because of a strong family history may be more cost-effective but this has not been established. No RCTs are planned in this group, but a screening study has been established. This will provide some evaluation using intermediate outcomes of screening but may also increase demand for screening services.

Authors' methods: Systematic review.

Project Status: Completed

URL for project: http://www.hta.ac.uk/972

Year Published: 1998

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: England, United Kingdom

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk

Copyright: 2009 Queen's Printer and Controller of HMSO