Featured Study: POSITIVE

Every quarter, Cancer Trials Ireland features a recent Journal Publication, including a short note on the study’s importance from an author. 

Prof Janice Walshe, Consultant Medical Oncologist

The POSITIVE (Pregnancy Outcome and Safety of Interrupting Therapy for women with endocrine responsIVE breast cancer) clinical trial allows women with breast cancer to pause their treatment to try to become pregnant.

Is it safe for young women with hormone-sensitive breast cancer to temporarily interrupt their endocrine treatment to permit pregnancy?
The answer is a resounding yes.

Fertility and pregnancy are priority concerns for young breast cancer survivors. A women diagnosed with breast cancer will face 5-10 years of treatment, which may suppress her ovarian function and impair her fertility. When treatment is complete, pregnancy may no longer be possible.

The POSITIVE study evaluates the safety of interrupting endocrine therapy to permit pregnancy and to confirm past data that has supported claims that pregnancy after breast cancer is not dangerous even in women whose tumours are stimulated by female hormones. Accrual targets of 500 (globally) were surpassed. 518 women were enrolled at 116 institutions across 20 countries in 4 continents. This was an international collaboration. In Ireland 13 patients were recruited across four sites. Recruitment is now closed.

The study is conducted and coordinated by the International Breast Cancer Study Group (IBCSG) and will provide definitive and sound scientific data for patients that it is possible to have a baby after breast cancer. The study will continue until Dec 2028.

In October 2021 a paper appeared in The Breast journal (Vol 59, pages 327-338) about the POSITIVE trial entitled “Who are the women who enrolled in the POSITIVE trial: A global study to support young hormone receptor positive breast cancer survivors desiring pregnancy”. It reviews characteristics of participants in the POSITIVE study to provide insights into which patient populations and doctors considered it acceptable to interrupt ET to pursue pregnancy. Similarities and variations from a regional, sociodemographic, disease and treatment standpoint suggest specific sociocultural attitudes across the world.

The best available evidence suggests that pregnancy after breast cancer does not increase a woman’s risk of developing a recurrence from her breast cancer. There is also no indication of increased risk for delivery complications or for the newborn. Globally 307 babies were born on this study to date.

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