• E-mail
• Print
• Comment
• Font Size
• Digg
• del.icio.us
• Discuss article

HRT Use Results in Small but Real Rise in Ovarian Cancer Cases, Deaths: Study

Posted on: Wednesday, 18 April 2007, 21:00 CDT

By HELEN BRANSWELL

TORONTO (CP) - A massive British study has uncovered another risk associated with taking hormone replacement therapy - the once ubiquitous menopause treatment appears to increase a woman's chances of developing ovarian cancer.

The study, released online Thursday by the journal The Lancet, coincides with the publication of even further evidence of a link between breast cancer and hormone replacement therapy, published Thursday in the New England of Medicine.

Combined, they underscore the message the Canadian Cancer Society and others have been preaching about HRT since a large U.S. trial was stopped in mid-2002 when researchers found hormone therapy increased the risk of heart attack, stroke and breast cancer in post-menopausal women.

"It's just adding more concern about the role of hormone replacement therapy in the development of certain cancers," Heather Logan, the cancer society's director of cancer control policy, said of the new studies.

"And in the absence of particular health benefits, when women have other options (for the relief of menopausal symptoms) I think they very strongly should consider them."

And women who do choose to use hormone replacement therapy should follow a simple rule, said Dr. Valerie Beral, the lead author of the ovarian cancer study in the Lancet.

"I think the general 'If you have to take it, take it for a short time' is still the right message," she said in an interview Wednesday.

The increased risk of ovarian cancer is small, but statistically significant, according to the Lancet study, led by researchers at Oxford University. It suggests that over a period of five years, one additional woman out of 2,500 HRT users would be diagnosed with the often fatal disease, and one in 3,300 would die.

"It's not a big effect, but it's a fatal effect," said Beral, a professor of epidemiology at Oxford.

"And so it's sort of that balance between saying 'No it's not huge, but people are more likely to die and die in a rather awful way."'

The article is based on data drawn from the Million Women Study, the largest study of its kind in the world.

British women aged 50 and older who went for breast cancer screening between 1996 and 2001 were invited to enrol in the study. Those who agreed were asked to provide information about their lifestyle - for instance, how much exercise they got and how much alcohol they drank - and whether they took hormone replacement therapy.

The study is meant to answer a number of questions about the possible impact of HRT use on breast and ovarian cancer rates.

For the purpose of this particular analysis, study researchers compared ovarian cancer rates and deaths among three groups of women: those currently taking HRT, women who had taken it but had stopped, and those who had never taken the hormone therapy.

They found that on average, current HRT users were 20 per cent more likely to develop ovarian cancer and die from it than women who never used hormone therapy. Put another way, for every 1,000 women using HRT, 2.6 would develop ovarian cancer over five years, compared to 2.2 per 1,000 women who never used it.

Women who had taken HRT but stopped were at no greater risk of developing ovarian cancer or dying from it than women who'd never taken it - a perplexing finding that Beral admitted she could not explain.

In total, the study estimated that HRT use had resulted in 1,300 additional cases of ovarian cancer in Britain since 1991 and 1,000 additional deaths in that time period.

HRT use in many countries dropped off dramatically after the 2002 report from the Women's Health Initiative. In Canada, prescription data amassed by IMS Health show that the number of prescriptions filled annually dropped from 12.6 million in 2001 to 5.5 million in 2006. The numbers declined in each year of that period.

The trend suggests researchers ought to start to see a drop in ovarian cancer rates, similar to what American researchers have shown about a decline in breast cancer rates in the U.S., Dr. Steven Narod, a breast and ovarian cancer expert at Toronto's Women's College Research Institute, said in a commentary published in the Lancet.

Researchers from The University of Texas M. D. Anderson Cancer Center reported at a scientific meeting last December that they'd seen a sharp drop off in breast cancer cases that closely echoed the decline in HRT use. The rate of new cases declined 6.7 per cent in 2003 - an extraordinary development.

That preliminary finding was fleshed out in this week's New England Journal article, with the researchers - Dr. Peter Ravdin, a professor of biostatistics and Donald Berry, head of the division of quantitative sciences - reporting that the trend levelled off but remained low in 2004.

That suggests the 2003 decline wasn't merely a blip, or as Ravdin put it in a press release, it was "not a one-year wonder, a short-lived anomaly."

"This kind of study can't prove causality, but the data present a very compelling link between hormone replacement therapy and breast cancer," added Berry.

Further strengthening their argument was the fact that the decline was predominantly seen in what's known as estrogen-receptor(ER)-positive cancer - the type of breast cancer fuelled by estrogen, the major component of HRT. ER-positive cancers declined 14.7 per cent compared to a 1.7 per cent decline in ER-negative cancers.

A similar study looking at what happened to breast cancer rates in Canada after the drop in use of HRT has not yet been conducted.

Source: Canadian Press

More News in this Category