Excess Ovarian Cancer Deaths Attributed to HRT Use

NEW YORK APR 18, 2007 (Reuters Health) - Since 1991, there have been roughly 1000 ovarian cancer deaths ascribed to the use of hormone replacement therapy (HRT) in the UK, according to a report in the April 19th issue of The Lancet. 

Previous reports have indicated that ovarian cancer is the fourth most common malignancy in women in the UK, but there are few data regarding the proportion of cases related to HRT use.

In the Million Women Study, Dr. Valerie Beral, from the Cancer Research UK Epidemiology Unit in Oxford, and colleagues addressed this issue by analyzing data from 948,576 postmenopausal women who were cancer-free at baseline.  They were followed for 5.3 years on average for incident ovarian cancer and 6.9 years for death. 

Thirty percent of the women were current HRT users and 20% of the women were past users, the report indicates.  During follow-up, 2273 women developed ovarian cancer and 1591 died from it.

Compared with never users, current HRT users were 20% more likely to develop ovarian cancer (p = 0.0002) and 23% more likely to die from it (p = 0.0006).  The risk of ovarian cancer was directly related to the duration of HRT use.  Past HRT users were not at increased risk for the malignancy.

HRT use was more strongly linked to serous type ovarian cancers than to those with mucinous, endometrioid, or clear cell histology.

Further analysis indicated that for every 2500 users, one extra case of ovarian cancer would occur, and for every 3300 users, an extra fatal case would arise. 

"Use of HRT has declined greatly 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," Dr. Steven A. Narod, from the Women"s College Research Institute in Toronto, Canada, notes in a related editorial.

SOURCE:

• Lancet 2007.