Ovarian cancer screening and mortality in the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS)
Ovarian Cancer Australia – Organisational statement compiled by Dr Katherine Nielsen, Director, Research and Advocacy
Last May, an important study led by Prof. Ian Jacobs was published causing great excitement in the ovarian cancer community. The study revealed that a screening strategy utilising a known test, CA125, in a sophisticated protocol (multimodal screening using the ROCA® test and ultrasound scan) could identify cases of ovarian cancer, including the aggressive type, before symptoms were experienced. And it did so with acceptable sensitivity and specificity, being able to detect 85 out of every 100 women with ovarian cancer, and ruling it out over 99% of women without the disease. ROCA® uses serial CA125 measurements to measure change over time to obtain a better picture of the individual’s risk of developing ovarian cancer – personalised detection at work!
Prior to this study, the landscape was bleak for early detection and reputable organisations globally had made recommendations against screening for ovarian cancer. But the Jacobs study provided new hope that early detection was possible. It required a huge collaborative effort to show this – the UKCTOCS trial was conducted over 14 years with more than 200,000 participants – an impressive endeavour and a testament to the dedicated team who conducted the research.
However, there are many barriers to developing a population screen, and demonstrating early detection was not enough. The next crucial step was to demonstrate a survival benefit in the intended screening population (post-menopausal women over 50). In the research world, it was a well-planned moonshot. Today, the results of this analysis were published demonstrating, for the first time, evidence that this screening strategy can save lives. The researchers reported a 20% reduction in mortality rates using the screen. It wasn’t entirely clear cut – the primary analysis was less impressive, although the same trend was identified. When the researchers looked into the data, they saw a lag time in benefit, with survival better in the long term than the short term, suggesting that there were a number of prevalent cases at the start of the trial. Reanalysis of the data, excluding these cases, provided a more robust analysis. Overall, this study is a huge step forward in early detection.
However there are many more steps to take. Yes, there is a survival benefit, but is it large enough to warrant a population screen? Longer term follow up will be needed to establish this. Furthermore, for any government to establish a population screen, economic analyses need to be conducted to determine its cost effectiveness.
And we should not stop here. The ROCA® Test cannot detect all ovarian cancers and up to 15% of women with ovarian cancer may be missed by the ROCA® Test. The screening strategy itself is more complex than a simple test, so there may be a need not only to improve efficacy, but also simplify the process – and how this could be done is not yet clear. There have been numerous studies on other biomarkers, and even though none have come close to delivering these sort of results, this study paves the ways for biomarker research to expand the ROCA approach.
Whether ROCA becomes a population screen or not, there may be other groups that might benefit it now, such as women who are at higher risk of developing ovarian cancer than the general population. We would like this test to be made accessible and affordable in Australia, to provide more options for women at risk. In the meantime, while we wait for improved early detection, symptom awareness is ever important, and remains the key to achieving a timely diagnosis.
Read more on this research here.
Genetic research and gene patenting
Ovarian Cancer Australia recognises the importance of genetic research in the international effort to improve outcomes from ovarian cancer and other diseases. In addition, women need equitable access to gene testing to make decisions about their personal cancer risk and to inform decisions of their family members who may also carry the gene mutation. Advances in research that involve the identification of panels of gene mutations that may have potential for identifying targeted therapies, more efficacious treatment choices and ultimately improved outcomes for women are promising. We recognise that patent laws serve to promote the development of new drugs and tests to improve health outcomes, however it is also important that the patenting of genes does not reduce access to genetic testing or introduce barriers to the international research effort.