It may be time to reassess the value of hormone replacement therapy, following evidence that it reduces the effectiveness of breast screening and causes breast cancer in women over the age of 50, says a leading breast surgeon in this week's BMJ. Increasing numbers of women in their 50s and 60s are using hormone replacement therapy to alleviate menopausal symptoms, yet the effect of long term use of these agents in women aged over 50 on the breast is only now becoming apparent.
In many women, hormone replacement therapy increases breast density. This affects both the sensitivity and specificity of breast screening because the effectiveness of breast screening depends on the decreasing breast density normally seen with age.
In countries where hormone replacement therapy is widely used, this reduction in the sensitivity of breast screening could undermine the capacity of national breast screening programmes to reduce deaths due to breast cancer, explains the author.
Studies of early hormone replacement therapy reported an increased risk of breast cancer for each year of use. More recent studies have reported significantly higher levels of risk in women taking combined hormone preparations compared with women taking oestrogen alone.
The evidence that hormone replacement therapy reduces the effectiveness of breast screening and causes breast cancer in women over the age of 50 is clear, says the author. The challenge for clinicians is to control menopausal symptoms while limiting these unwanted effects, he concludes.