Hormone replacement therapy (HRT), a contested treatment for
post-menopausal women that has already been linked to breast
cancer, is also associated with ovarian cancer, a study in The
Women who take HRT are on average 20 percent likelier to develop
and die from ovarian cancer compared to women who have never been
on this treatment, according to the research.
The evidence comes from a major British investigation into
female health, the Million Women Study, covering 1.3 million
British women from 1996-2001.
HRT entails taking substitutes for oestrogen or progesterone
after natural levels of these key female hormones diminish after
The idea behind it is to reduce symptoms such as hot flushes and
vaginal dryness and boost protection against osteoporosis and heart
How the study was conducted
The British researchers assessed data from 948 000
post-menopausal women, who had been questioned and later given a
follow-up exam some three years later.
Around 30 percent were current HRT users; 20 percent had
previously received HRT; and the remaining 50 percent had never
Across all three groups, a total of 2 273 women developed
cancer, and 1 591 died from it.
The increased risk of cancer, though, was shouldered by current
HRT users, especially those who had been taking the hormones for at
least five years. The risk was largely unchanged by such factors as
a smoking habit or past use of oral contraceptives.
Women who had stopped HRT had the same risk level as
counterparts who had never taken the treatment.
Enormous numbers exposed
In a commentary, Steven Narod of the Women's College Research
Institute in Toronto, Canada, said the relative risk of 20 percent
might be thought of as small, "but enormous numbers of women have
In the Million Women Study alone, nearly 500,000 had taken HRT,
he pointed out.
Extrapolated across the British population, around 1 000 extra
women died from ovarian cancer between 1991 and 2005 because of
The HRT link with breast cancer surfaced in 2002, prompting many
women in the United States to drop the treatment - a trend that
notably coincided with a sharp fall in new breast cancer cases in
The authors of the new study are led by Valerie Beral of the
Cancer Research UK Epidemiology Unit in Oxford, Britain. The paper
appears in next Saturday's issue of The Lancet.
Beral says HRT's effect should be seen in the context of breast
and endometrial (uterine wall) cancer, as well as ovarian cancers. These three types of tumour account for 40 percent of all cancers
diagnosed in British women.
"The total incidence of these three cancers in the [Million
Women Study] population is 63 percent higher in current users of
HRT than never-users," the study notes. – (Sapa-AFP)