Studies - Breast Cancer

Hormone Replacement Therapy (HRT) Increases Cancer Risk

Women who take hormone replacement therapy are at a greater risk of developing ovarian cancer and dying from the disease, say scientists.

Researchers at Oxford University concluded that 1,000 British women may have died from ovarian cancer since 1991 because they took the drug to relieve the unpleasant symptoms of menopause and prevent brittle bone disease.

The new findings emerged from the Million Women Study, the largest examination of HRT and cancer, which questioned almost 950,000 women aged 50 to 64.

Previous results from the same study showed that using combined HRT doubled a woman’s risk of developing breast cancer compared with not taking HRT.

In the latest paper, published in The Lancet, scientists at Cancer Research UK’s Epidemiology Unit in Oxford found that the rate of ovarian cancer among those who took HRT was 2.6 per 1,000 women over five years.

For women who did not take the drug, the incidence dropped to 2.2 per 1,000 over the same period.

This meant that over a five-year period there was likely to be one additional case of ovarian cancer among 2,500 women receiving HRT, the team said.

For every 3,300 women on HRT there was also likely to be one additional death from the disease.

It thus has, since 1991, been responsible for some 1,300 additional ovarian cancers and 1,000 additional deaths. [20Apr07, Telegraph]

The researchers said that a woman’s risk of developing ovarian cancer returned to a normal level within a few years of stopping HRT.

Ovarian cancer is the fourth most common cancer in women in the UK with almost 7,000 new cases every year. The five-year survival rate for the disease is less than 30 per cent.

Prof Valerie Beral, director of Cancer Research UK’s epidemiology unit, said: “The results of this study are worrying because they 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.”

Prof John Toy, the charity’s medical director, said: “Considering [the risk of ovarian cancer] alongside the increase in risk for breast and endometrial cancer, women should think very carefully about whether to take HRT. And women who choose to take HRT should aim to do so for clear medical need and for the shortest possible time.”

However, critics accused the researchers of “replacing science with sensationalism” and urged women not to stop taking the treatment.

The number of women taking HRT dropped from two million in 2002 to one million in 2005 after a number of health scares.

A proportion of women has since returned to the drug because they were desperate to find relief from menopausal symptoms.

“There is no doubting the results of this well-conducted research, though, which followed nearly a million women from 1991, when HRT was given for much longer periods and to far more women.

“In the past five years, the number taking the treatment has more than halved, and current recommendations are to use it for only two to three years. So although the dramatic report of 1,000 extra deaths may be correct (and it is the very top estimate), they occurred over 15 years: that’s far fewer than 100 women a year.

“Much of medicine is about managing risk, and doctors are used to this. There’s an upside and a downside to every intervention: just like in everyday life, driving a car, crossing the road or going skiing all have their risks. And while this study adds ovarian to breast and endometrial cancers as being firmly associated with HRT, the risk is still relatively small and, for most people, HRT is worth taking if the benefits are great.

“There are alternatives, of course – non-oestrogen drugs, herbal remedies, special diets, psychological techniques – but when the symptoms are severe, none is as effective as HRT. So-called natural oestrogens from plants (phyto-oestrogens) are claimed to be safer and some women swear by them, but no large-scale research has been conducted.” [HRT: kill or cure?, 20April, Telegraph.co.uk, Karol Sikora]

The women in the study were invited to join when they received their invitation to attend breast screening. None had a previous record of cancer.

They were monitored for up to seven years. During the follow-up period a total of 2,273 women developed ovarian cancer and 1,591 died from the disease.

[19April2007, http://www.telegraph.co.uk/portal/main.jhtml?xml=/portal/2007/04/20/nosplit/fthrt20.xml, Telegraph.co.uk, By Nicole Martin]