A comprehensive new report on hormone replacement therapy (HRT) and the development of breast cancer was published in 1997. This leaflet explains what that research showed and what it means for you.

The benefits of HRT

HRT is effective in relieving unpleasant symptoms of the menopause and, when taken for several years, prevents fractures which are caused by thinning of the bones (osteoporosis). It may also reduce heart disease.

HRT and breast cancer

For some time it has been thought possible that more cases of breast cancer are diagnosed in women who use HRT than in those who do not. Research confirms this, and also finds that those breast cancers found in women on HRT are easier to treat than those in women not on HRT. The chances of developing breast cancer are higher for those who use HRT for many years. Those who use it for a short period around the menopause are hardly affected.

For women aged 50 not using HRT, about 45 in every 1000 will have cancer diagnosed over the next 20 years, that is up to age 70. For those who use HRT for long periods of time, the estimated number of extra cancers is shown below.

Length of time on HRT Extra Breast cancers in HRT users, above the 45 occurring in non-users, over 20 years
5 years use 2 per 1000
10 years use 6 per 1000
15 years use 12 per 1000

The extra chance of developing breast cancer on HRT does not persist beyond about 5 years after stopping treatment.

What to do if you are concerned

If you are on HRT this research does not mean that you need to stop taking it. If you are concerned and want to know more, you should make a routine non-urgent appointment with your doctor.

All women, and especially those on HRT, should be aware of any changes that occur in their breasts, and report them to their doctor. All women aged between 50 and 64 are invited to have regular, three yearly, mammograms, and those 65 and over may have them on request.

Source: MCA 1997