Breast Cancer and Pregnancy: POSITIVE Study Welcome

Kathy D. Miller, MD


December 28, 2015

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Hi. It's Dr Kathy Miller from Indiana University, back with another Medscape Oncology video blog. I haven't been with you for a while, and I want to make you aware of two pieces of information specifically about pregnancy and birth outcomes in our patients with cancer.

First, make your way to the November 5 issue of the New England Journal of Medicine, and you'll find a case-control study from the International Network on Cancer, Infertility, and Pregnancy (INCIP) that looked at 129 babies born to women who were diagnosed and treated for their cancer during pregnancy and compared them with a matched cohort of children with mothers who did not have a cancer diagnosis or treatment during pregnancy.[1] The good news: no difference in outcomes. There was no difference in gestational age, size for gestational age, cognitive development, and incidence of cardiac disease or cardiac malformations. This is great news for our patients who, in the midst of pregnancy, are diagnosed with cancer and need treatment.

Now on the flip side, many of you know that I spend most of my time treating patients with breast cancer. The issue I'm often faced with is pregnancy after diagnosis and treatment in my young patients with cancer. We've talked before in this forum about the results of the Prevention of Early Menopause study (POEMS),[2] suggesting that using ovarian suppression during chemotherapy can facilitate preservation of fertility and successful delivery of babies after treatment. However, this study was in patients with estrogen receptor (ER)-negative disease.

In our patients with ER-positive disease, it gets a whole lot more complicated. We need to think both about the hormonal milieu associated with pregnancy and what impact that might have. We also need to think about the impact of interrupting antiestrogen therapy to allow for pregnancy. This has really been a data-free zone, with very little information to guide these patients.

However, among the international community, a study has started, known as the Pregnancy Outcome and Safety of Interrupting Therapy for Women With Endocrine Response Breast Cancer (POSITIVE) trial,[3] investigating pregnancy outcomes in women with ER-positive disease. This trial will enroll patients who are premenopausal; have ER-positive tumors; and have a history of antiestrogen therapy for a duration of 18-30 months, and are now at a point where they desire conception.

The trial will investigate stopping their antiestrogen therapy to allow for conception and delivery, with the goal of being off antiestrogen therapy for a maximum of 2 years. After delivery and breastfeeding, if possible and desired by the woman, she will then resume antiestrogen therapy to complete at least a total 5-year duration.

This study is not randomized, but it has a goal of enrolling 500 women worldwide. It will track success of those conception attempts, health of the women, recurrence of their breast cancer, new cancers, and health of the babies, and will give us a tremendous amount of really important information to guide those discussions with our younger patients.

I want to make sure you all are aware of this trial. It is an incredibly important trial for these patients, and one they really want and need us to conduct. If you're seeing a young patient who is premenopausal, has ER-positive disease, and is interested in pregnancy, please join the POSITIVE trial so that her data can contribute to our understanding of these important issues even more. Be sure check out the New England Journal of Medicine for some good news about the health of the babies born to our patients.

I'll be seeing you again soon. This is Kathy Miller, from Indiana University.


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