- 14 March 2019 -

The POSITIVE trial: answering an important question for young women, Pregnancy

The POSITIVE trial: answering an important question for young women

Intro text: 

For many young women undergoing hormone treatment for endocrine-responsive early breast cancer, the question of if and when they can stop therapy to become pregnant is high on their list [1].


Retrospective and population-based analyses support the safety of pregnancy and breast feeding after breast cancer in women at low risk of recurrence. However, there is no direct evidence about the risks of stopping hormone treatment within the typical five years and up to 10 years of therapy in the approximately 15% of patients who are diagnosed with breast cancer during their reproductive years.

Following extensive discussion through the BIG-NABCG collaboration, the large international POSITIVE trial has been set up to produce clear evidence about the safety of interrupting cancer treatment.

“This is a very important study for young women with breast cancer. At present, if a woman is diagnosed with breast cancer in her early 30s, by the time she has completed treatment, it may be too late to start a family. With the POSITIVE study, we hope to answer that important question of whether it is safe to take a break from treatment,” says Professor Martine Piccart, BIG co-founder and chair.

The POSITIVE study is aiming to recruit 500 premenopausal women with ER+ early breast cancer who received endocrine therapy for 18 to 30 months, are 42 years of age or younger at enrolment, and wish to interrupt endocrine therapy to become pregnant. Women will take a three-month break in treatment before attempting pregnancy and stop treatment for up to two years to allow time for conception, delivery and breastfeeding (or potential failure to conceive). Endocrine therapy will then restart and continue for the duration of treatment.

By end of December 2018, 339 women with ER+ early breast cancer had been recruited to POSITIVE in 20 countries, and 57 healthy babies had been born. Women will be followed up for 10 years after enrolment and initial results are expected in the next few years.

1. Pagani O, Ruggeri M, Manunta S et al. Pregnancy after breast cancer: Are young patients willing to participate in clinical studies? Breast. 2015 Jun;24(3):201-7.