The Health Ministry has issued stronger warnings on the dangers of hormone replacement therapy (HRT) after international studies showed it doubled the risk of dementia and increased cases of blood clots, strokes and breast cancer.
The first caution in September 2002, by the Medicines Adverse Reactions Committee (MARC), stated HRT should be reviewed at the time of the next prescription.
Today, however, the ministry issued a statement saying treatment should be reviewed six-monthly and HRT should be taken at the lowest dose for the shortest period of time.
Ministry adviser Dr Stewart Jessamine said the new advice had been prompted by two recent studies examining the safety of both combined HRT and oestrogen-only HRT, which are used to treat menopause symptoms.
The risk of developing breast cancer associated with HRT use was “relatively small”, causing an additional six breast cancers per 1000 women after five years use of HRT, he said.
“However, the studies all demonstrate that the risks of HRT treatment outweigh the benefits for everything other than for short-term use to relieve moderate to severe symptoms caused by the menopause.”
An extremely large research programme in Britain, The Million Women Study, showed:
the risk of breast cancer is seen within one to two years of commencing HRT and increases with duration of use,
all forms of HRT are associated with an increased risk of developing breast cancer,
the risk of breast cancer decreases after stopping HRT, and within five years the residual risk is not significantly different from that observed for women who have never used HRT.
Another large scale US based study of 16,000 women, The Women’s Health Initiative Memory Study (WHIMS), found combined HRT doubled the risk of developing dementia.
The study estimated that use of combined HRT in women aged 65 years and over would produce an extra 23 cases of dementia per 10,000 women per year, with the increased risk becoming noticeable after one year of combined HRT treatment.
Women should be advised of the risks associated with use of hormone replacement therapy (HRT) before treatment begins, and be carefully monitored during its duration, Dr Jessamine said.
HRT should no longer be used for the primary or secondary prevention of cardiovascular disease (heart attack or stroke).