Screening for ovarian cancer did not reduce deaths
13 May 2021
A large-scale randomised trial of annual screening for ovarian cancer did not succeed in reducing deaths from the disease, despite one of the screening methods tested detecting cancers earlier.
Results from the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) were published yesterday in the medical journal The Lancet.
In the UK, 4,000 women die from ovarian cancer each year. It is not usually diagnosed until it is at a late stage and hard to treat.
In UKCTOCS, two screening methods were compared to no screening, to see if they could pick up ovarian cancer earlier, when treatments are more likely to be effective, and save lives.
The latest analysis looked at data from more than 200,000 women aged 50-74 at recruitment between 2001 and 2005, who were followed up for an average of 16 years. The women were randomly allocated to one of three groups: about 100,000 to no screening, and just over 50,000 each to annual screening using an ultrasound scan, and annual multimodal screening involving a blood test followed by an ultrasound scan as a second line test. Screening lasted until 2011.
The researchers found that, while the approach using multimodal testing succeeded in picking up cancers at an early stage, neither screening method led to a reduction in deaths.
Earlier detection in UKCTOCS did not translate into saving lives. Researchers said this highlighted the importance of requiring evidence that any potential screening test for ovarian cancer actually reduced deaths, as well as detecting cancers earlier.
Professor Usha Menon (MRC Clinical Trials Unit at UCL), lead investigator of UKTOCS, said: “UKCTOCS is the first trial to show that screening can definitely detect ovarian cancer earlier. However, this very large, rigorous trial shows clearly that screening using either of the approaches we tested did not save lives. We therefore cannot recommend ovarian cancer screening for the general population using these methods.
“We are disappointed as this is not the outcome we and everyone involved in the trial had hoped and worked for over so many years. To save lives, we will require a better screening test that detects ovarian cancer earlier and in more women than the multimodal screening strategy we used.”
Blood test screening picked up 39% more cancers at an early stage (Stage I/II), while detecting 10% fewer late-stage cancers (Stage III/IV) compared to the no screening group. There was no difference in the stage of cancers detected in the ultrasound group compared to the no screening group.
The initial analysis of deaths in the trial occurred in 2015, but there was not enough data at that time to conclude whether or not screening reduced deaths. By looking at five more years of follow up data from the women involved, researchers are now able to conclude that the screening did not save lives.
Professor Mahesh Parmar, Director of the MRC Clinical Trials Unit at UCL and a senior author on the paper, said: “There have been significant improvements in the treatment of advanced disease in the last 10 years, since screening in our trial ended. Our trial showed that screening was not effective in women who do not have any symptoms of ovarian cancer; in women who do have symptoms early diagnosis, combined with this better treatment, can still make a difference to quality of life and, potentially, improve outcomes. On top of this, getting a diagnosis quickly, whatever the stage of the cancer, is profoundly important to women and their families.”
Professor Ian Jacobs, from the University of New South Wales (UNSW Sydney), a co-investigator who has led the ovarian cancer screening research programme since 1985 and who was lead investigator of UKCTOCS from 2001-2014, said: “Population screening for ovarian cancer can only be supported if a test is shown to reduce deaths in a future randomised controlled trial. I remain hopeful that a new effective screening test will be found eventually, but it will take many years to conduct a large trial of the test. Realistically, this means we have to reluctantly accept that population screening for ovarian cancer is more than a decade away.”
A huge wealth of samples and data from the trial has been donated by the participants for future research. This resource, referred to as the UKCTOCS Longitudinal Women’s Cohort (UKLWC), is now being used by researchers worldwide, helping to improve understanding of ovarian cancer as well as other cancers and other diseases such as cardiovascular disease.
The current follow-up of UKCTOCS was funded by the NIHR HTA Programme, and the charities Cancer Research UK and The Eve Appeal. The initial trial was funded by the EME Programme, an MRC and NIHR partnership and the Cancer Research UK and The Eve Appeal charities.