Menopause therapy cancer risk

MENOPAUSAL hormone therapy (MHT) has been linked to an increased risk of breast cancer which can persist for more than a decade after usage stops.

For every 100 women using oestrogen plus daily progestogen MHT, two extra cases of breast cancer were identified between age 50 and 69, according to researchers from the University of Oxford.

After stopping use, some excess

risk was found to persist for more than 10 years – with the size of the risk linked to the duration of previous use.

The researchers said that if the associations are causal, this means MHT use has already caused around one million breast cancers in western countries – one-twentieth of the total since 1990.

The global analysis used data from more than 100,000 women with breast cancer from 58 epidemiological studies worldwide.

The researchers found that all types of MHT, except topical vaginal oestrogens, were linked to an increased risk of breast cancer.

The risks were greater for users of oestrogen-progestogen hormone therapy than for oestrogen-only hormone therapy.

Women tend to begin MHT at around the time of the menopause, when ovarian function ceases, causing symptoms including hot flushes and discomfort. There are about 12 million users in Western countries – about six million in North America and six million in Europe, including one million in the UK.

Although regulatory bodies in Europe and the USA recommend MHT be used for the shortest time that is needed, some clinical guidelines recommended less restrictive prescribing. About five years of use is now common.

Co-author Professor Valerie Beral, from the Nuffield Department of Population Health, University of Oxford, said: “Our new findings indicate that some increased risk persists even after stopping use of menopausal hormone therapy.

“Previous estimates of risks are approximately doubled by the inclusion of the persistent risk after use of the hormones ceases.”