Screening for ovarian cancer did not reduce early deaths
From: University College, London
May 13, 2021 -- The latest analysis
looked at data from more than 200,000 women aged 50-74 at recruitment who were
followed up for an average of 16 years. The women were randomly allocated to
one of three groups: no screening, annual screening using an ultrasound scan, and
annual multimodal screening involving a blood test followed by an ultrasound
scan as a second line test.
A large-scale randomised trial of annual screening for ovarian cancer,
led by UCL researchers, 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) have been published in a report 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. UKCTOCS was designed to test the hypothesis that a reliable
screening method that picks up ovarian cancer earlier, when treatments are more
likely to be effective, could save lives.
The latest analysis looked at data from
more than 200,000 women aged 50-74 at recruitment who were followed up for an
average of 16 years. The women were randomly allocated to one of three groups:
no screening, annual screening using an ultrasound scan, and annual multimodal
screening involving a blood test followed by an ultrasound scan as a second
line test.
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."
Women aged between 50 and 74 were
enrolled in the trial between 2001 and 2005. Screening lasted until 2011 and
was either an annual blood test, monitoring changes in the level of the protein
CA125, or a yearly vaginal ultrasound scan. About 100,000 women were assigned
to the no screening group, and more than 50,000 women to each of the screening
groups.
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: "My thanks to the thousands
of women, healthcare professionals and researchers who made this trial
possible. The multimodal screening strategy did succeed in detection of ovarian
cancer at an earlier stage, but sadly that did not save lives. This is deeply
disappointing and frustrating given the hope of all involved that we would save
the lives of thousands of women who are affected by ovarian cancer each
year."
Professor Jacobs noted: "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.
Researchers say that the study has also
generated insights into how best to design, conduct and analyse a large-scale
randomised clinical trial particularly in individuals who have no signs of
disease. These insights will be helpful to future trials in all areas of
health. It has also contributed to advances in risk assessment, prevention and
diagnosis of ovarian cancer.
The UKCTOCS trial was funded by the NIHR
Health Technology Assessment (HTA) Programme and the charities Cancer Research
UK and The Eve Appeal.
Michelle Mitchell, Cancer Research UK's
Chief Executive, said: "Trials don't always find the result we had hoped
for, but we need long-term studies like this to know whether new tests save
lives. Cancer Research UK will continue to fund vital research into aggressive
forms of ovarian cancer so we can reduce the impact of this disease.
"Screening is for people without
symptoms, so it's still important that if you notice unusual or persistent
changes to talk to your doctor. Symptoms of ovarian cancer can be quite vague
and similar to symptoms caused by less serious conditions, which can make
spotting the disease tricky. Whether it's needing to go to the toilet more
often, pain, bloating, or something else, raise it with your GP -- in most
cases it won't be cancer but it's best to get it checked out."
Professor Nick Lemoine, Medical
Director, NIHR Clinical Research Network, said: "These important findings
from a large-scale trial, involving 200,000 participants, show that annual
screening did not succeed in reducing deaths from ovarian cancer.
"However, it's important to note
that negative results can be as important as positive. The study has provided
important new evidence and insights into how to conduct and analyse future
large-scale randomised clinical trials into ovarian cancer, in the hope that
this will prevent and diagnose this disease more effectively in the future.
"We thank every single person who
took part."
Athena Lamnisos, CEO, The Eve Appeal,
said: "The threshold for introducing a national cancer screening programme
is a mortality benefit. Of course this is key -- saving lives. It's
disappointing that this research programme did not show a reduction in
mortality from ovarian cancer and so can't be recommended as a national
screening programme. However, the impact it had on earlier diagnosis is
impressive and important.
"Ovarian cancer is so often
diagnosed at stage 3 or 4 and shifting diagnosis one stage earlier makes a huge
difference to both treatment options and quality of life. Earlier diagnosis
will often reduce the amount and intensity of treatment, and this makes all the
difference to women and their families who are living with cancer. It may have
also given them more precious time with their loved ones."
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