In the Journal of the American Medical Association on July 17, 2002 Lacey and co-workers studied participants in the US Breast Cancer Detection Demonstration Project, a nationwide breast screening program. 

Of the total number of 44,241 participants, all postmenopausal, 329 women were identified who developed ovarian cancer. 

• Among those who had never used hormone therapy the chance of developing ovarian cancer was 4.5 cases per 1000 women per 10 years of observation. 
• Among those who used estrogen alone that rate was 7 cases per 1000 over ten years. 

This is equivalent to an extra risk of 2.5 cases per 1000 over ten years ie. 1 in 400 chance of developing an ovarian cancer because of long-term use of estrogen alone. 

The use of combined hormone therapy (as occurred in the Women's Health Initiative Report, in the same issue of the Journal) was not associated with any increase in risk.

The lifetime risk of developing ovarian cancer is normally approximately 1 in 100. 

It should be noted that this study is not strong from a statistical point of view, but does add to some others suggesting that there may be a small increase in absolute risk of developing ovarian cancer in long-term users of postmenopausal estrogen. 

A number of other studies have not confirmed this observation.

August 7, 2002
Professor Henry Burger 
Chairman, Research Committee, 
The Jean Hailes Foundation

Article

Menopausal Hormone Replacement Therapy and Risk of Ovarian Cancer
Lacey JV Jr, Mink PJ, Lubin JH, Sherman ME, Troisi R, Hartge P, Schatzkin A, Schairer C.
(JAMA. 2002 Jul 17;288(3):334-41)

Content updated August 07, 2002