Hormone replacement therapy and risk of malignancy

The fact that today our concern is oriented towards the risks rather than the benefits of hormone replacement therapy could be the clearest message about our current position. The safety of hormone replacement therapy, an estrogen-progestin combination which has been sympathetic to and supportive of disturbing menopausal symptoms of women, is seriously challenged.

Four randomized trials have now reported on the results of hormone replacement therapy in major potentially fatal conditions, in more than 20,000 women studied for about 5 years. The main concern regarding the increased risk of malignancy in healthy postmenopausal women in western countries has been breast cancer. It is estimated to cause an extra case in about six per 1000 users aged 50-59 and 12 per 1000 aged 60-69. Over the same period the estimated risk of endometrial cancer rates are not increased, with a relative risk of 0.76 per 1000 users aged 50-59. Overall, however, the increased incidence of malignancies is greater than any reduction, one per 230 users aged 50-59 and one per 150 aged 60-69. Randomized trials examining other important but rarer malignancies, like ovarian, gall bladder and urinary bladder cancer, are either nonexistent or too small to reliably describe any effects of hormone replacement therapy.

Conclusively epidemiological evidence suggests that hormone replacement therapy is associated with a small but substantial increase in breast cancer risk and combined estrogen-progesterone regimens further increase this hazard. Additionally, the evidence from the recent double blind placebo controlled randomized trial on the slight increase in the incidence of adverse cardiovascular events, has turned our orientation away from hormone replacement therapy as a long term therapy in postmenopausal women. In this review, the effort is to approach comprehensively and globally the information on the risks of hormone replacement therapy on several cancer sites.