Whether or not HRT increases the risk of breast cancer is still unresolved. Studies suggest that five years of treatment is associated with minimal risks but there may be a small risk if HRT is continued for more than 10 years. Numerous studies are under way to evaluate the risk more clearly.
The possible effect of HRT on breast cancer should be considered against the background of a one in 12 lifetime risk of developing this disease, compared with a one in four risk of having a heart attack. A woman’s risk of hip fracture has been estimated to be about one in six – equivalent to the combined lifetime risk of developing breast, womb and ovarian cancer.
Other factors such as family history and benign breast disease may also influence the risk of breast cancer, although these need not be a contraindication to HRT. Current medical research suggests that there may be a link between inherited genes and breast cancer. Therefore a positive history of breast cancer in a close relative may be an important indicator of your own increased risk of breast cancer.
An interesting point is that women who develop breast cancer while taking HRT appear to be more likely to survive than women who are not on HRT. This may reflect a difference in the type of cancer that evolves or could arise from increased detection of early cancers which would not normally develop. Only further research will reveal the true answer.
However, it is important to be aware of your individual risk; the more risk factors you have from the list, the greater your risk. If you are at high risk of breast cancer, have minimal risk of heart disease or osteoporosis, then you may decide against HRT. If you have severe menopausal symptoms you might choose to take HRT for just a few years. The choice is very much an individual one, depending on your personal circumstances.
HRT for women treated for breast cancer
There are increasing moves to offer HRT to women who have been treated for breast cancer. The decision to start treatment is based on the individual merits of each case, but may be recommended if symptoms of oestrogen deficiency are particularly severe. HRT does not appear to interfere with tamoxifen, a drug used in the treatment of breast cancer and which has some properties similar to those of oestrogen.