Pregnancy 'protects against breast cancer'

  • Deborah Condon

Women who get pregnant after battling breast cancer are not at an increased risk of dying from the disease. In fact, pregnancy may improve their chances of future survival, European researchers have said.

Breast cancer is the most common cancer diagnosed in women during their childbearing years. As women delay starting families until they are older, and survival from breast cancer has improved, an increasing number of breast cancer survivors want to have babies after their treatment has finished.

Until now, it was unclear whether it was safe for them to do so, due to concerns that the hormonal changes associated with pregnancy, in particular the increase in oestrogen, could prompt the cancer to recur or become more aggressive.

Italian and Belgian researchers analysed 14 trials that had taken place between 1970 and 2009. The trials involved 1,417 pregnant women with a history of breast cancer and over 18,000 women with a history of breast cancer who were not pregnant.

They found that patients who became pregnant following a diagnosis of breast cancer had a 42% reduced risk of death compared to breast cancer survivors who did not get pregnant.

“Our findings clearly demonstrate that pregnancy is safe in women with a history of successfully treated breast cancer. There is a wide perception in the oncology community that women with a history of breast cancer should not get pregnant for fear of pregnancy increasing the risk of recurrence by means of hormonal stimulation. This analysis strongly argues against this notion,” commented lead researcher, Dr Hatem Azim of the Institute Jules Bordet in Brussels.

The team is now refining the results by analysing subgroups to examine the effect of the timing of pregnancy, for example, how soon after a breast cancer diagnosis is it safe to become pregnant.

“It is still common that patients are faced with incorrect counselling regarding pregnancy and the chances of future fertility following the end of breast cancer treatment and, thus, they are denied the chance of getting pregnant. It is important to provide a high level of evidence to help physicians in counselling these patients.

“This work may result in improving the quality of life of millions of young women who finish their breast cancer therapy and want to get pregnant,” Dr Azim insisted.

The researchers said that there may be a number of explanations related to hormones or the immune system to explain why pregnancy appears to confer a protective effect on breast cancer survivors.

Details of these findings were presented at the 7th European Breast Cancer Conference in Barcelona.

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