Screening might help to detect ovarian cancer before symptoms develop. The first analysis of screening for ovarian cancer currently being investigated in the UKCTOCS (UK Collaborative Trial of Ovarian Cancer Screening) trial is published in Lancet Oncology today (11th March 2009).

Preliminary results from UKCTOCS show that in the first screen of the 100,000 women participating in the screening arms of the trial, screening detected ovarian cancer or borderline tumours in 87 women and missed picking up 13 women who went on to develop the disease within a year of screening. Almost half (48%) of the 58 cancers detected were at an early stage. The Lancet Oncology paper does not report on cancers in the 100,000 women included in the control arm of the trial who are not being screened; this is in accordance with current NHS guidelines as there is no ovarian cancer screening programme. Cancers that developed in women in the screening arms in the subsequent years of the study are not reported in this first analysis.

Speaking about the early results, lead investigator Professor Ian Jacobs, director of the UCL (University College London) Institute for Women’s Health, stressed: ‘‘There is a long way to go before we have firm evidence as to whether or not screening is able to detect cancer early enough to save lives. It will also be essential to balance any benefits offered by screening with the downside, as it is recognised that screening can cause anxiety and lead to some unnecessary operations.’’

‘‘The UKCTOCS trial is the largest trial of its kind ever run to investigate ovarian cancer and we are enormously grateful to the women who have taken part. It will conclude in just over 5 years and if the findings are positive my hope is that what we learn will pave the way for a national ovarian cancer screening programme.”
Ovarian cancer is most common in women who have gone through menopause and diagnosis is usually when cancer is already in the advanced stages. Women from 27 Primary Care Trusts in England, Wales and Northern Ireland were asked to join the study. All of the 200,000 women recruited to the trial between 2001 and 2005 through the 13 participating NHS Trusts were postmenopausal and aged between 50 and 74 years old. Following the initial screen, reported in this Lancet paper, women are continuing to be invited for further screening until 2011. Everyone will be followed up until December 2014.

Two screening methods are being used in the UKCTOCS trial: a blood test or an ultrasound scan. The blood test measures levels of a protein called CA125 that is often elevated in the blood of women who have ovarian cancer. The research team used statistics to determine risk of ovarian cancer based on the woman’s age, how much CA125 was present and how the level changed with time. The ultrasound scan is used to look for abnormalities in the ovaries. Approximately 50,000 women were allocated to screening using the blood test and a further 50,000 to ultrasound to measure the efficacy of these screening methods.

If a volunteer’s blood test result suggested risk of ovarian cancer, the woman was recalled for additional screening and follow up; 97 had surgery to remove the ovaries and 42 women with ovarian cancer were identified in this group.

Women in the ultrasound group who were found to have persistent abnormalities were referred for a specialist opinion; 845 had surgery to remove the ovaries and 45 women with ovarian cancer were identified in this group. The research team found both methods of screening were encouragingly sensitive. Almost half the cancers detected were at an early stage (I or II).

The research team suggest that the higher number of repeat tests and surgical procedures in the ultrasound group could be attributed to the number of older women who have benign ovarian cysts which are detected by ultrasound. A proportion of these women have to undergo surgery and examination of the ovarian tissue before diagnosis of ovarian cancer can be ruled out.

The study is being run from the Gynaecological Cancer Research Centre, UCL Institute for Women’s Health. As the trial progresses, researchers will continue to monitor how many of the 202, 638 women develop ovarian cancer. In the 101,000 undergoing screening the team will monitor how many of cases of cancers are detected and at what stage. They will also record how many women have surgery.

Dr Usha Menon, UKCTOCS trial co-ordinator and one of the principal investigators said: “These results are extremely encouraging. We’d like to thank all of the women involved in the trial and to encourage them to continue helping us by attending for screening until the end of the trial. The early results suggest that both types of screening can be used on a large scale and both successfully identify ovarian cancers. However, we must wait till 2015 before we can conclude whether or not a wider screening programme could lead to a fall in deaths due to ovarian cancer.”

The UKCTOCS trial has been funded by the Medical Research Council, Cancer Research UK and the National Institute for Health Research and is supported by gynaecological cancer research charity The Eve Appeal.

Professor Ian Jacobs concluded: “I believe the UKCTOCS trial is an example of UK healthcare at its best. It is a combination of a huge research effort, involving charity, research council and Government funders, hospital staff, university researchers and GPs around the UK and crucially more than 200,000 women. The first results are an important step forward and the trial itself is a powerful demonstration of how our best scientists, clinical researchers and healthcare workers in the UK collaborate in research and involve volunteers nationwide to improve health.’’

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Notes to editors

Original research paper: Sensitivity and specificity of multimodal and ultrasound screening for ovarian cancer, and stage distribution of detected cancers: results of prevalence screen of the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) is published in Lancet Oncology.
UKCTOCS trial website: http://www.ukctocs.org.uk/