First evidence to suggest that screening for ovarian cancer may save lives
17 Dec 2015
New results from the world’s biggest ovarian cancer screening trial suggest that screening based on an annual blood test may help reduce the number of women dying from the disease by around 20 per cent.
The research, published in the Lancet, also cautions that longer follow up is needed to establish more certain estimates of how many deaths from ovarian cancer could be prevented by screening. Estimates from the results so far are promising, but the exact figures remain uncertain.
The UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) is an international ovarian cancer screening trial, led by UCL and funded by the MRC, Cancer Research UK, Department of Health and The Eve Appeal.
Ovarian cancer was diagnosed in 1,282 women during the 14-year study of more than 200,000 post-menopausal women aged 50 to 74, of whom 649 had died of the disease by the trial end in December 2014.
The study showed a delayed effect on mortality between the screening and control arms, which became significant after the first seven years of the trial. The research team are now following up the study for three more years to establish the full impact of ovarian cancer screening.
The early results suggested that approximately 15 ovarian cancer deaths could be prevented for every 10,000 women who attend a screening programme that involves annual blood tests for between seven to 11 years.
The trial also confirmed previous findings that on average, for every three women who had surgery as a result of an abnormal screen, one woman had ovarian cancer while two women did not. For those who had surgery, around three per cent had major complications, which is the standard complication rate for this type of surgery in the NHS.
The screening blood test, called ROCA uses a statistical calculation to interpret changing levels over time of a blood protein called CA125, which is linked to ovarian cancer. This gives a more accurate calculation of a woman’s individual risk of having ovarian cancer, compared with an alternative method which uses a one-off blood test measuring a fixed ‘cut-off’ point for CA125. The ROCA is licensed to Abcodia Ltd, a UCL spin out company.
Study author Professor Ian Jacobs, President and Vice-Chancellor of UNSW Australia and Honorary Professor at UCL, who co-invented the ROCA in 1996 and is also a non-executive director of Abcodia Ltd. said: "I am delighted that the UKCTOCS results suggest that early detection by screening can save lives. Longer follow up is needed but this brings hope in the fight against a disease for which the outlook for women is poor and has not improved much during the last three decades."
Professor Usha Menon, UCL Women’s Health, who co-led the trial and receives research funding from Abcodia, said: “UKCTOCS has been an immense research effort spanning 14 years, over 200,000 women and 700,000 annual screens. Finally we have data which suggests that screening may prevent ovarian cancer deaths. This is welcome news and provides fresh impetus for renewed efforts in this area.”
How the results were found
The trial involved 202,638 post-menopausal women aged 50 to 74 who were randomly assigned to annual multimodal screening using the Risk of Ovarian Cancer Algorithm (ROCA), annual transvaginal ultrasound, or no test.
Initial analysis of the results across the 14 years of the trial found a reduction in ovarian cancer mortality due to screening that did not reach statistical significance. However, after further analysis that allowed for the delay between entry into the trial and developing the disease, and excluding women with evidence of already having ovarian cancer at entry, the statistically significant results suggest that screening reduces the number of women dying of ovarian cancer by around 20% over the 14 years of the study. The study allows us to be almost certain that screening reduces the number of women dying from ovarian cancer by somewhere between 0% and 40%, so further follow up is required to narrow this estimate.
Based on the ROCA test score, a woman’s risk is categorised as either normal – where she should continue with annual screening; intermediate – requiring a repeat blood test in 3 months or elevated – where a repeat blood test is required along with and a transvaginal ultrasound in 6 weeks.
To read about the grant(s) that funded this research, please see Gateway to Research reference G9901012.