Women were advised yesterday to think
“very carefully” about taking hormone
replacement therapy (HRT) after evidence was
published showing that it has killed 1,000
women in Britain since 1991 by increasing
their risk of ovarian cancer.
HRT increases the risk of the disease by
20 per cent, the biggest investigation of
links between HRT and cancer has found.
Although the absolute risk is low, millions
of women took HRT in the 1990s and so the
total impact is large: an extra 1,300 cases
of the disease and 1,000 deaths between 1991
and 2005, according to the Million Women
Previous results from the same study have
linked HRT with an increased risk of breast
and womb cancer. The latest findings suggest
that HRT raises the combined risk of all
three diseases by more than 60 per cent, the
Despite a sharp decline in recent years
in HRT use, there are believed to be about
one million women in Britain still on it.
Valerie Beral, director of the Cancer
Research UK epidemiology unit at the
University of Oxford, said: “The results of
this study show that not only does HRT
increase the risk of getting ovarian cancer,
it also increases a woman’s risk of dying of
Ovarian cancer is the fourth most common
cancer in women in Britain. Each year about
6,700 women develop the disease and 4,600
die from it.
The findings come from a study of 948,576
post-menopausal women, or a quarter of all
women aged 50 to 64 in the country. It was
largely funded by Cancer Research UK. About
a third of those in the study were taking
HRT, and another fifth had taken it in the
The women were followed for an average of
more than five years for signs of ovarian
cancer, and seven years for death. During
the follow-up period a total of 2,273 women
developed ovarian cancer and 1,591 died from
These results imply that the use of HRT —
of whatever sort — increased the risk of
developing and dying from ovarian cancer by
20 per cent, the team reports in the online
version of The Lancet.
To put the findings in perspective, they
mean that over a period of five years there
is likely to be one extra case of ovarian
cancer among every 2,500 women receiving HRT,
and one additional death for every 3,300
women on the therapy.
HRT is used to combat unpleasant symptoms
of the menopause, including hot flushes,
vaginal dryness and night sweats. It was
promoted strongly by doctors in the 1970s,
and many women claimed that it had
transformed their lives.
But in recent years numbers have
plummeted after a series of health scares.
According to the GP Research Database, the
number of women in Britain on HRT fell from
two million in 2002 to one million in 2005.
John Toy, the medical director of Cancer
Research UK, said: “Considering this
alongside the increases in risk for breast
and endometrial cancer, women should think
very carefully about taking HRT. Women who
choose to take HRT should aim do so for
clear medical need and for the shortest
The findings were challenged by John
Stevenson, of the Royal Brompton Hospital in
London and the chairman of the charity
Women’s Health Concern.
“The study grossly overestimates the
breast cancer risk, and now we have findings
from a five-year study that have to be
extended to a 14-year time frame to make
them more sensational,” he said. “This is
not science, and the findings themselves fly
in the face of cancer biology.”
Breast, ovarian and endo- metrial cancer,
which affects the womb lining, account for
almost 40 per cent of cancers in women in
Britain, and a quarter of female cancer
HRT appears to raise the combined risk of
all three diseases by 63 per cent, according
to the Million Women Study.
“When ovarian, endometrial and breast
cancer are taken together, use of HRT
results in a material increase in these
common cancers,” the study authors wrote.