Wilhelm Braendle, professor in the Department of Gynaecologic Endocrinology and Reproductive Medicine at the University Hospital in Hamburg-Eppendorf, and colleagues examined the data of 10,000 women. MEDICA.de spoke with the physician about the results of his study, the influence of estrogen and gestagen and the sensitive handling of it.
MEDICA.de: Mr Braendle, some years ago two studies conducted in Great Britain and the USA received a lot of attention: it was found that breast cancer risk was significantly raised by hormone replacement therapies. However, in Germany the study was criticised: gynaecologists in this country would prescribe other amounts and hormones and, hence, the results would therefore not apply to Germany. You have again conducted a study that mirrors the German situation. Can you give an all-clear for Germany?
Wilhelm Braendle: No, I cannot give the all-clear. We too observed that the incidence of breast cancer rises with the intake of hormones. Regarding the long-term intake the risk is clearly increased. Women must be informed about that because around half of all women in the menopause take additional hormones.
MEDICA.de: You claim that the breast cancer risk increases only if the hormone replacement therapy lasts five years or longer.
Braendle: After five years the risk is significantly higher, before it is not. However, the risk continues to rise the longer the hormones are taken. We have calculated the increase per year: for estrogen alone, the risk rises by one percent per year; for the continuously combined estrogen-gestagen therapy, in contrast, it increases about five percent per year.
MEDICA.de: You have also observed that five years after stopping the hormone replacement therapy breast cancer risk drops again to a base level. Why?
Braendle: We believe that the hormones influence tumour growth. That means that latent tumours which are basically cancer cells that already exist in the body but are not visible yet are stimulated by the hormones to grow quicker. If the hormone therapy is interrupted or finished the tumour growth slows down again.
MEDICA.de: That means that the hormones are not to blame for the occurrence of tumours?
Braendle: Exactly. The cancer cells are already present in the breast tissue. Without hormones the tumour would just start to grow later. It is not possible to define when exactly, though.
MEDICA.de: Each hormone replacement therapies must be tailored to individual patient’s needs which also affects the duration of taking the hormones. Does taking hormones for the course of five years reflect reality?
Braendle: Yes, definitely. Most women suffer from meonpausal side effects over a period of four to five years. Taking hormones for only a few weeks, on the contrary, almost never happens.
MEDICA.de: Why does an estrogen monotherapy - which raises breast cancer risk less - works differently than a combined estrogen-gestagen therapy?
Braendle: We are not sure about that yet. We know that differences exist in general. Gestagens, for example, do affect the breast differently than the endometrium: in the latter, gestagen prevents cancer. We are still analysing this, however.
MEDICA.de: In the aftermath of the studies from the USA and Great Britain it had come to a strong decline in hormone replacement therapies in the USA and simultaneously to a decline of breast cancer.
Braendle: This happened all over the world, not only in the States! It also occurred in Germany. However, regarding our results, we think that the rate of breast cancer will rise again: the occurrence has been postponed because tumours keep growing, also without hormones, only a lot slower. By taking a close look over a long time period it will show that the number of people developing breast cancer does not change. This means that not more women fall ill with breast cancer through hormone replacement therapy, the affected persons fall ill in younger age.
MEDICA.de: Well, what do you advise women with a lot of discomfort during menopause?
Braendle: I would inform them about the advantages and risks of hormone replacement therapy. After that, the woman must decide herself whether she wants to accept the existing relatively low, but definitely significant risk. It also has to be pointed out that it is not possible to just prescribe an estrogen monotherapy for every woman because with that therapy the risk for developing breast cancer is lower. The type of therapy depends on individual considerations.
MEDICA.de: You did not give an all-clear for Germany. Does that mean no more hormone replacement therapies?
Braendle: No, the result of our study should certainly not be interpreted this way. Women should take the hormones they have opted for but should check in regular intervals whether they still need them and stop as soon as possible. Principally, taking the hormones for shorter time periods such as two years, for example, the women should be on the safe side.
The interview was conducted by Anke Barth.