HORMONE REPLACEMENT THERAPY: BREAST CANCER
As a general guideline, the chances of developing breast cancer increase with the length of time you take HRT, and also the higher the dose of oestrogen. There appears to be no significant risk to women in the population at large who take it for less than five years, but the risk increases slightly between 5 and 10 years, and taking it for more than 15 years gives a higher risk still. (It is this long-term risk that has attracted media attention, though often the scare-mongering headlines are quite unjustified medically.) This can cause problems, because long-term oestrogen use is important for preventing osteoporosis, heart attack and stroke; and many women also feel so good on it that they would be very reluctant to give it up after just a few years.
Cancer is a very real fear for doctors and patients alike. Nobody wants to get it, but the risk needs to be put into perspective. Under the age of 50, deaths in women from breast cancer out-number deaths from coronary heart disease and stroke combined. However, after the age of 50,
this ratio is reversed, and far more women die from a heart attack or stroke than from breast cancer. Oestrogen reduces by 50 per cent your chances of having a heart attack or stroke.
The risks of developing breast cancer as a direct result of taking HRT are small when set against the protection it confers against osteoporosis and arterial disease, although it is important to say here that if you take progestogen in the therapy, then some of the protection against heart attack may be reduced. Progestogen’s effect on breast cancer is not clearly known; some researchers have concluded that it offers some protective effect, others that it may have a negative effect, and others still that it has no effect at all. More research is clearly needed here.
It is thought that oestrogens neither increase nor decrease the risk of cancer of the ovaries in post-menopausal women compared with those who do not take it; and oestrogen and progestogen appear to have no effect on the incidence of cancer of the cervix.
One important thing that has been noted is that, although there is a higher rate of breast cancer among women who take HRT than among those who don’t, their survival rate is also higher. In other words, if you develop breast cancer and are on HRT, you have a better chance of surviving than if you develop breast cancer and are not on HRT. This is possibly because regular screening of women on HRT picks up any breast problems in the very early stages, when treatment is more likely to be effective. Some studies have also suggested that tumours linked to oestrogen therapy might be less virulent and invasive than other types of tumours, and that these particular tumours respond to treatment better than tumours not linked to oestrogen therapy.
A tremendous amount of research is being carried out into all aspects of HRT and the menopause. Hopefully, the time will come when doctors will know more clearly which particular sub-group of women would be more at risk of developing breast cancer if they took HRT, so that they can leave it well alone, and the rest can take it with confidence and safety.
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