It is suspected that the lifestyle and the fewer pregnancies can provoke the disease, which strikes one out of every ten Danish women.

During the last century mamma cancer has become the most frequent type of cancer among women of the western industrial countries. In Denmark there are almost 3000 new cases every year, i.e. at least one in every ten Danish women will get cancer at one point in their lives.

During the last couple of years we have become more successful in our treatment of patients with mamma cancer via a systematic development of improved treatment and the use of new diagnostic methods. Consequently, fewer women die from mamma cancer even though the number of cases increases. But we are far away from curing the disease. It is still a mystery why the disease so often breaks out in the mammary gland. In the age group between 45 and 55 mamma cancer is the disease, which causes the largest number of deaths in Denmark (13%).

The prevention of a disease requires knowledge concerning the origin of the disease. Studies of immigrants moving from an area with a low prevalence to an area with a high prevalence of mamma cancer – e.g. Japanese moving to Hawaii and Poles moving to the US - show that the immigrant's risk of developing the disease increases gradually in correspondence with the new home country. This fact indicates that the risk for developing mamma cancer is connected to the conditions, lifestyle and environment of the population and not so much the genetic factors.


Menstruation and overweight
Unfortunately, we do not know that much about the causes of mamma cancer but it seems that the disposition for developing mamma cancer is developed quite early in life and is connected to the hormonal influences of the mammary gland tissue, i.e. particularly oestrogen (the female sex hormone). An early commencement of menstruation, a late termination of menstruation or the use of oestrogen during a longer period of time could cause an increased influence. Too much fat tissue, i.e. overweight, could also imply a larger production of the oestrogen hormone in the body and thereby present a larger risk.

On the other hand pregnancy seems to protect against mamma cancer: the more pregnancies the smaller the risk – maybe because the number of menstruation periods influence the development of the disease. Finally, the more recent examinations indicate that exercise to some extent can reduce the risk of mamma cancer – once again maybe via a changed production of oestrogen. All in all it is, however, quite limited what you can do to prevent cases of mamma cancer by use of the present knowledge.


Also hereditary conditions
Almost 10 % of the cases of mamma cancer have a hereditary component, i.e. it appears in families, which are particularly exposed to cancer.

By examining women with mothers, sisters and other relatives with mamma cancer for genetic changes, you can estimate the risk and offer guidance with greater certainty than before.

While recognising that to a large extent prevention is not possible, the effort is concentrated on early diagnostics and screening. All over the world large screening programs have been carried out by the use of mammography – a x-ray examination of the mammary gland tissue. There is still disagreement concerning the effect of this screening on mortality and we do not have any good examinations concerning the costs for the women, who show changes that, later on, prove to be insignificant – the so-called false positive examinations. All together it must be concluded that mammography on a regular basis can lower the mortality of mamma cancer with women over 50 years of age (with younger women the examination is not appropriate) – and imply that more women only have to undergo surgery where only the tumour itself is removed.


Surgery, medicine and radiation
The treatment of cancer patients consists of a combination of surgery, medicine and radiotherapy. Primarily, the mammary gland tissue including the tumour and the nearby lymph glands are removed (equivalent to the armpit). If the tumour is big, looks aggressive under a microscope or if there are any tumour cells in the removed lymph glands, the patient should be offered medical treatment and some times radiotherapy following the surgery. If the tumours are hormone sensitive, i.e. they contain so-called hormone receivers; the medical treatment will consist of substances, which influence the function or production of the female sex hormones. In other cases cytotoxic drugs are used to destroy the cancer cells left in the body. A cytotoxic treatment is given during 6 to 9 months after the operation while the hormonal treatment is usually given during 5 years.

With some of the patients the disease returns either "locally" in or near the breast or as distant metastasis in for example bones, liver or lungs and the treatment here will also consist of medicine. Consequently, you can achieve a reduction of the tumours and thereby a prolonged survival and less symptoms. Relapses typically appear within the first 10 years after the first diagnosis. Mamma cancer does, however, differ from most of the other types of cancer, as the relapses can appear very late, i.e. up to 20 to 30 years after the first operation.

In other words women treated for mamma cancer have a greater risk for relapses for the rest of their lives.