Hormone Replacement Therapy

HRT is supplementary oestrogen in the form of oestradiol. The preparations provide maintenance of the natural oestrogen levels when the ovaries fail around the menopause, in doses of only 10-20% of that of the contraceptive pill but with fewer of the pill's risks. HRT can be initiated before the periods cease and continue for as long as is appropriate for the woman. It is recommended that HRT is generally only given for five years after the menopause.

Benefits

1. Prevention of hot flushes, mood swings, dry vagina and altered libido.

2. Prevention of osteoporosis. HRT is an effective method of preventing osteoporosis, however advice from December 2003, is that is should not be used just for this purpose. HRT leads to an increase in bone mineral density for the duration of use which on stopping declines at the previous rate. At 5 years of use a 70 year old lady would therefore have the bones of a 65 year old and be less likely to sustain a fracture of the spine, hip or wrist.

3. There is a slight reduction in the risks of Bowel Cancer.

4. There is thought also to be a slight reduction in the risk of Alzheimer’s disease.

Disadvantages

1. Breast Cancer.

It is well known there is a link between oestrogens and breast cancer, there is a slightly increased risk in women who start their periods early, and continue for longer. Additionally there is a slight risk of uterine and ovarian cancer.

The recent UK Million Women Study has again shown a link with breast cancer. See the chart below which summarises the increased risks.

2. Ovarian Cancer

In April 2007 the Million Women Study reported once again and found an increased risk of ovarian cancer in women taking HRT. These are only small increases but should be taken into account when considering whether HRT should be commenced or continued. See the chart below for details of this increased risk.

3. Uterus

There is a small increase in this cancer but the progestogen in combined HRT largely protects against this.

Risks of developing cancer on HRT: Number of Cancers/1000 patients

	Non Users	HRT for 5 years	HRT for 10 years
Breast (50-65yrs)	32	+1.5 Oestrogen	+5 Oestrogen
		+6 Combined	+19 Combined
Ovary (50-69yrs)	2.2	+ Oestrogen or Combined	+3 Oestrogen of Combined
Uterus (50-69yrs)	9	+4 Oestrogen	+10 Oestrogen

4. Thrombosis

It has now been clearly shown that there is a doubling of the risks of thrombosis or blood clot; but this is only really relevant with patients either having had a previous clotting episode or those with a very strong family history of such. More concerning is that there is also an increase in heart attacks which was previously thought to be reduced.

5. Stroke

There is a small increase in the risk of having a stroke in women in their 50’s on HRT; this goes up when women reach their 60’s.

6. Heart Attack

It used to be thought that HRT protected women from heart attacks; we now know this is not true.

Risk of thrombo-embolic events on HRT. No. of events per 1000 women

	In Non-Users	On HRT
Blood Clot	3	7
Stroke (in 50's)	3	4
Stroke (in 60's)	11	15
Heart Attack	...	Just under 1/year

HRT is therefore appropriate for the management of menopausal symptoms, but it should be used for the shortest duration, ideally not longer than 5 years. It is appropriate in women who experience a premature menopause up to the age of 50. HRT should now not be used solely for osteoporosis prevention. Further information is available from http://www.mhra.gov.uk.

References

-Risk and Benefits of Estrogen plus progestin in healthy post menopausal women JAMA 2002 www.jama.com

-Breast cancer and hormone replacement therapy in the Million Women Study. Lancet 2002; 362:419
-Risk of ovarian cancer in the Million Women Study, Lancet April 2007 www.thelancet.com