The POSITIVE Study
Can you pause hormone therapy to try for a baby?
That’s the question this trial set out to answer. Between 2014 and 2019, more than 500 premenopausal women aged 42 or younger—all with hormone receptor–positive breast cancer—joined the study after completing 18–30 months of endocrine therapy. They chose to pause treatment for up to 2 years to try for pregnancy.
What Happened?
Here’s what researchers found among participants who tried to conceive:
74% Became Pregnant
A rate equal to or higher than the general population*
70% Conceived Within 2 Years
of those who became pregnant did so within two years.
Live Birth Rate of 86%
86% of Pregnancies resulted in live births
2% Birth Defects
Not clearly associated with exposure to cancer treatments. **
8.9% Breast Cancer Recurrence
Compared to 9.9% among patients who did not pause endocrine therapy in a different large study. ***
What It Means
- A temporary break in hormone therapy may be safe in the short term.
- Long-term safety is still being studied.
- Resuming endocrine therapy after pregnancy is strongly recommended to lower recurrence risk.
Who Were the Participants
- Median age: 37
- Diagnosis: mostly Stage I or II
- 75% had no prior births
- Over 50% had received chemotherapy
- Most were taking Tamoxifen
Watch this video of Ann Partridge, MD, MPH, founder and director of Young and Strong, and Leticia Varella, MD, as they discuss results from the POSITIVE trial.
Learn how persons with hormone-positive breast cancer may temporarily interrupt endocrine therapy to pursue pregnancy and hear directly from a patient who had a baby after breast cancer.
References
* Partridge AH, Niman SM, Ruggeri M, et al; International Breast Cancer Study Group; POSITIVE Trial Collaborators. Interrupting Endocrine Therapy to Attempt Pregnancy after Breast Cancer. New Endl J Med. 2023 May 4;388(18):1645-1656. Doi: 10.0156/NEJMoa2212856. PMID: 37133584
