Active monitoring of prostate cancer has the same high survival rates
after 15 years as radiotherapy or surgery, reports the largest study of
its kind today.
The latest findings from the ProtecT trial are presented today at the
European Association of Urology (EAU) Congress in Milan and published in
the New England Journal of Medicine.
Although men on active monitoring – which involves regular tests to check
on the cancer – were more likely to see it progress or spread than those
receiving radiotherapy or surgery, this didn’t reduce their likelihood of
survival.
The trial also found that the negative impacts of radiotherapy and
surgery on urinary and sexual function persist much longer than
previously thought – for up to 12 years.
The findings show that treatment decisions following diagnosis for low
and intermediate risk localised prostate cancer do not need to be rushed,
according to lead investigator, Professor Freddie Hamdy from the
University of Oxford.
“It’s clear that, unlike many other cancers, a diagnosis of prostate
cancer should not be a cause for panic or rushed decision making,” he
said. “Patients and clinicians can and should take their time to weigh up
the benefits and possible harms of different treatments in the knowledge
that this will not adversely affect their survival.”
The trial, funded by the National Institute for Health and Care Research,
was led by researchers at the Universities of Oxford and Bristol in nine
UK centres and is the longest running study of its kind. It is the first
to fully evaluate three major treatment options: active monitoring,
surgery (radical prostatectomy) and radiotherapy with hormones for men
with localised prostate cancer.
Between 1999 and 2009, 1,643 men aged 50-69 years across the UK, who were
diagnosed with localised prostate cancer after a PSA blood test, agreed
to be randomised to active monitoring (545), radical prostatectomy (553)
or radical radiotherapy (545). The research team followed the men over an
average of 15 years, to measure mortality rates, cancer progression and
spread, and the impact of treatments on quality of life.
They found that around 97% of the men diagnosed with prostate cancer
survived 15 years after diagnosis, irrespective of which treatment they
received. Around a quarter of the men on active monitoring had still not
had any invasive treatment for their cancer after 15 years.
Patients from all three groups reported similar overall quality of life,
in terms of their general mental and physical health. But the negative
effects of surgery or radiotherapy on urinary, bowel and sexual function
were found to persist much longer than previously thought.
In earlier findings released in 2016, the researchers found that, after
ten years follow up, men whose cancer was being actively monitored were
twice as likely to see it progress or metastasise than those in the other
groups. The assumption had been that this might lead to a lower survival
rate for men on active monitoring over a longer time period. However, the
results from the 15-year follow up show that this isn’t the case and that
survival rates remain similarly high across all groups.
Lead investigator, Professor Freddie Hamdy from the University of Oxford,
said: “This is very good news. Most men with localised prostate cancer
are likely to live for a long time, whether or not they receive invasive
treatment and whether or not their disease has spread, so a quick
decision for treatment is not necessary and could cause harm.”
“It’s also now clear that a small group of men with aggressive disease
are unable to benefit from any of the current treatments, however early
these are given. We need to both improve our ability to identify these
cases and our ability to treat them.”
Co-investigator, Professor Jenny Donovan, from the University of Bristol,
said: “Patients and doctors now have the necessary information on the
long-lasting side effects of treatments to better understand the
trade-offs between their benefits and harms. Survival no longer needs to
be considered when deciding on treatment – as that’s the same for all
three options. Now men diagnosed with localised prostate cancer can use
their own values and priorities when making the difficult decisions about
which treatment to choose.”
The trial has also highlighted flaws in current methods to predict which
prostate cancers are likely to grow quickly and spread. Initially, all
those recruited to the trial were diagnosed with localised cancer and 77%
of them were deemed low risk. A reassessment using more modern methods
showed that a far greater number would now be considered
intermediate-risk – and in around 30% of men, the disease had spread
beyond the prostate already. This means that the participants in the
study had higher grade and stage disease than was thought initially.
Despite this finding, mortality was still low, even when men with
intermediate disease delayed or did not have radical treatment. Some of
the men who subsequently died of their prostate cancer had been assessed
as low risk at diagnosis, which the researchers highlight as an issue of
concern.
Professor Peter Albers, chair of the EAU’s Scientific Congress Office and
a urologist at Düsseldorf University, said: “The fact that the greater
progression of disease seen under active monitoring didn’t translate into
higher mortality will be both surprising and encouraging to urologists
and patients. Active monitoring and biopsy protocols today are much more
advanced than at the time this trial was conducted, so it’s possible we
could improve on these outcomes still further. It’s an important message
for patients that delaying treatment is safe, especially as that means
delaying side effects as well.”
“But it’s also clear that we still don’t know enough about the biology of
this disease to determine which cancers will be the most aggressive and
more research on this is urgently needed.”
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