Barcelona, Spain: Women who have been treated for breast cancer can choose to become pregnant and have babies, without fears that pregnancy could put them at higher risk of dying from their cancer, according to a major, new study.

In a meta-analysis of 14 trials, presented today (Friday) at the seventh European Breast Cancer Conference, researchers from Belgium and Italy found that, not only was pregnancy safe for breast cancer survivors, but, in fact, it could improve their chances of survival.

The researches are now refining the results by analysing subgroups to examine the effect of the timing of pregnancy - for instance how soon after a breast cancer diagnosis is it safe to become pregnant - and differences in survival according to the patient's age, lymph node status and so on.

Dr Hatem A. Azim, Jr., a Fellow at the Department of Medical Oncology at the Institute Jules Bordet (Brussels, Belgium) said there might be a number of explanations related to hormones or the immune system as to why pregnancy seemed to confer a protective effect on breast cancer survivors.

It was explained by Dr. Azim that although oestrogen is associated with breast cancer development but beyond a certain level, the oestrogen exerts inhibitory effects on breast cancer cells. Furthermore, prolactin is elevated in pregnancy and there is evidence suggesting that women with high levels of prolactin have a reduced risk of breast cancer relapse.

Immunological theories could partially explain the possible protective value of pregnancy as well. It has been shown that foetal antigens* are expressed on the tumour cells of the mother. Thus, antibodies produced by the mother in response to these antigens, may act as a kind of tumour vaccination.

Dr Azim said that they had contacted all the authors of trials published after 1995 to get extra information on subgroups, and this would inform their further research.

He concluded: Nowadays, fertility after cancer has become a top issue not only for patients, but also physicians. In 2006, the American Society of Clinical Oncology published guidelines that state that fertility issues should be discussed with patients before treatment - a recommendation we believe is of great importance.

Medicine Breast cancer Cancer