In post-menopausal women, various hormone combinations have been used to treat conditions such as hot flushes, urogenital disorders. Relief from these disorders is sometimes obtained as well as a benefit in the short-term prevention of osteoporotic fractures, but numerous adverse effects have been observed, some of them severe: cardiovascular risks, especially that of thromboembolism, and an increase in the frequency of some cancers, especially breast cancer.

In 2002, the publication of a high-quality and large-scale trial (the WHI trial) showed that hormone replacement therapy (combining oestrogen and progesterone) leads to an increased number of breast cancers of 8 cases a year for 10,000 post-menopausal women treated, linked to the duration of exposure to the treatment.

In the USA, where the use of HRT decreased in 2002 then even more in 2003, the number of breast cancer cases is down 8.6%, more significantly in women aged 50 to 69. This fall has also been noted in France, Germany and Canada.

This example is a reminder that drugs must be thoroughly evaluated before using them to avoid severe adverse effects, instead of assessing them after the event. Otherwise it is the patients who pay the price.

©Prescrire January 2009

Source: "Traitement hormonal de la menopause et cancers du sein (suite)" Rev Prescrire 2008; 28 (302) 908-909.

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