HRT and cancer of the ovary - balancing the risks and the benefits

The hot flushes of the menopause are never fun, and for some women hormone replacement therapy, or HRT offers welcome relief. Now a new review of 52 studies, involving 21,488 women, has suggested a 40% increase in the risk of getting ovarian cancer.

Forty per cent sounds like a huge increase, but because ovarian cancer is much less common than breast cancer, this translates into an extra one in 1,000 women getting ovarian cancer, and an extra one in 1,700 women dying, as a result of taking HRT for five years. Previous studies had suggested a possible small increase, but most individual studies had been too small to assess the size of the risk from taking HRT for just a few years.

Until just over a decade ago, about two million women in the UK were using HRT. In 2002, a study called the WHI suggested a link between taking HRT and having a heart attack or stroke. Shortly afterwards, a UK trial called the Million Women Study suggested that one in 200 extra women taking combined (oestrogen and progesterone) HRT for five years, and one in 50 women taking it for ten years, would develop breast cancer. The number of women taking HRT dropped by over half within a few years.

But recently the pendulum has swung back again, with further studies and review of the original research. The WHI trial largely involved women in their 60s given high-dose HRT, and in fact there was no increased risk of heart attack or stroke in women taking HRT under the age of 60. One more recent study showed no increased risk of breast cancer in women taking HRT around the menopause, and the worst case scenario estimate is now around one extra case of breast cancer per 1,000 women taking HRT for each year they take it (although the risk may rise more after about seven years on HRT). Since most women take HRT for three to five years in their early-mid 50s, when hot flushes are at their worst, confidence has slowly been growing again in the risk:benefit ratio of HRT.

The newly uncovered risk of ovarian cancer appears to apply to women taking oestrogen only or oestrogen and progestogen HRT, and does not appear to depend on other factors like past use of oral contraception, weight, smoking, alcohol intake or family history of cancer. The risk drops again after stopping HRT, and within 10 years is little higher than that of a women who has never taken it.

Where does that leave women taking HRT today? As with so many medical dilemmas, there isn't an easy answer. Some women's lives are ruled - and wrecked - by hot flushes. There are alternatives to HRT but none of them banish hot flushes as effectively.

For some women, a one in 1,000 risk of ovarian cancer might be a chance worth taking to get control of their lives again. For others, taking any medicine that might lead them to a diagnosis of ovarian cancer is a step too far. As a doctor, all I can do is advise of the risks and the benefits, and ask my patient to make an informed decision. I have no right to decide for you - I'm not the one living with hot flushes.

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