1000 Extra Ovarian Cancer Deaths Due To HRT In UK Since 1991

Main Category: Ovarian Cancer
Also Included In: Women's Health / Gynecology;  Endocrinology
Article Date: 19 Apr 2007 - 1:00 PDT

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A suspected 1000 extra women in the UK have died from ovarian cancer between 1991 and 2005 because they were using Hormone Replacement Therapy (HRT), according to an Article published Online and in an upcoming edition of The Lancet.

There were also around 1300 extra cases of ovarian cancer diagnosed in the same period. The figures are reported in the "Million Women Study" by Professor Valerie Beral and colleagues, of the Cancer Research UK Epidemiology Unit, Oxford, UK.

Ovarian cancer is the fourth most common cancer in UK women, with about 6700 developing the condition and 4600 dying from it every year.

The researchers assessed data from 948 576 postmenopausal women who did not have previous cancer or bilateral oophorectomy (removal of the ovaries) for five years. Around 30% were current HRT users and 20% had previously received HRT. 2273 women developed ovarian cancer and 1591 died from it.

They found that current HRT users were on average 20% more likely to develop and die from ovarian cancer than those who had never received HRT. For every 1000 women using HRT, 2•6 developed ovarian cancer over five years, compared to 2•2 per 1000 in women who did not use HRT - one extra ovarian cancer diagnosed in every 2500 HRT users, and one extra death from ovarian cancer in every 3300 users. But risk did not differ significantly by type of HRT preparation used, its constituents, or mode of administration.

The women's socioeconomic status, reproductive history, previous use of oral contraceptives, body-mass index, alcohol and tobacco consumption did not appreciably alter the effect of HRT on their risk of developing ovarian cancer.

The researchers also reported that after women stop taking HRT, their risk of ovarian cancer returns to that found in never-users of HRT.

In total, ovarian, endometrial and breast cancer account for around 40% of all cancers diagnosed in UK women.

The authors conclude: "The effect of HRT on ovarian cancer should not be viewed in isolation, especially since use of HRT also affects the risk of breast and endometrial cancer."

They add: "The total incidence of these three cancers in the study population is 63% higher in current users of HRT than never users. Thus when ovarian, endometrial and breast cancer are taken together, use of HRT results in a material increase in these common cancers."

In an accompanying Comment, Dr Steven Narod, of the Women's College Research Institute, University of Toronto, Canada, said: "Use of hormone replacement has declined dramatically in the UK and elsewhere since the report of the Women's Health Initiative, and is thought to be responsible for a recent reduction in breast cancer rates recorded in the USA.

"With these new data on ovarian cancer, we expect the use of HRT to fall further. We hope that the number of women dying of ovarian cancer will decline as well."

www.lancet.com

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