Pregnancy after breast cancer treatment does not increase risk of recurrence

Women who have children after having breast cancer are not risking their survival, a new study has shown.

Professor Richard Anderson from the Medical Research Council Centre for Reproductive Health at the University of Edinburgh presented the findings at the annual meeting of the European Society of Human Reproduction and Embryology.

'This analysis shows that having a baby after breast cancer doesn't have a negative impact on survival,' said Professor Anderson. 'It provides reassurance for the growing number of women who want to start or complete their families after breast cancer treatment.'

Many types of breast cancer are hormone-sensitive, meaning that the tumour cells are stimulated to grow and multiply by the hormones oestrogen and progesterone. Because levels of these hormones rise during pregnancy, there has been concern that it could increase the chances of the cancer recurring.

To examine this hypothesis, the study used information from the Scottish Cancer Registry to identify over 5000 women aged below 40 who were diagnosed with breast cancer from 1981-2017. They were able to see which women subsequently had pregnancies and compare this to survival data up to 2018.

Of these women, 209 gave birth, and on average their survival rates were slightly better than those who did not have a pregnancy after breast cancer. The highest survival rates were among women who gave birth to their first child, especially those who were diagnosed youngest.

'This study supports existing evidence that women with breast cancer who go on to become pregnant do not put themselves at risk,' Dr Melanie Davies, consultant in reproductive medicine at University College London, told BioNews. 'This is important and reassuring information for young women with breast cancer who would like a family.'

The results also highlight the importance of fertility preservation for women having treatment for breast cancer:

Ephia Yasmin, clinical lead of the reproductive medicine unit at University College Hospital, London, told BioNews: 'Breast cancer is one of the commonest indications for fertility preservation prior to gonadotoxic treatment. This survival data from Professor Anderson and his team is extremely valuable when counselling patients with regards to future use of their gametes or embryos.'