Pregnancy following breast cancer using assisted reproduction and its effect on long-term outcome

We have previously shown that pregnancy is safe following breast cancer, even in endocrine sensitive disease. Yet infertility remains common following systemic treatment. To date, no study has evaluated the safety of assisted reproductive technology (ART) after breast cancer treatment. In this study, we evaluated the impact of ART on pregnancy and long-term outcomes of young breast cancer survivors.

This is a multi-centre retrospective study in which women who were diagnosed with breast cancer between 2000 and 2009, and had a pregnancy following breast cancer diagnosis were eligible. Patients were divided into two groups according to whether ART following primary systemic therapy was performed to achieve pregnancy. We evaluated the association between ART use and clinic-pathological characteristics, pregnancy outcome and long-term breast cancer outcome.

A total of 198 patients were evaluated; of whom 25 underwent ART. No significant differences in tumour characteristics were observed between both groups, except for histological grade 3 tumours, which were fewer in the ART group (36% versus 59%, p=0.033). Around 90% of patients received primary adjuvant chemotherapy and more than 50% had an endocrine sensitive disease. Patients in the ART group were older at diagnosis (31.4 versus 33.7 years, p=0.009), at conception (38 versus 35 years, p<0.001), and experienced more miscarriages (23.5 versus 12.6%, p=0.082). Full term pregnancies were achieved in 77% and 76% of the spontaneous and ART groups, respectively. Mean follow-up between conception and last follow-up was 63 and 50 months in the spontaneous and ART groups, respectively with no difference in breast cancer outcome observed between the two groups (p=0.54).

Pregnancy using ART in women with history of breast cancer is feasible and does not seem to be detrimental to cancer outcome. Larger studies are needed to further confirm this observation.