Pregnancy Does Not Lead to Breast Cancer Recurrence, Study Finds

Becoming pregnant does not increase a woman's chance of having her breast cancer recur, according to a recent study presented at ASCO.
While doctors and patients alike often worry that a pregnancy could cause a breast cancer recurrence, a recent study found that is not the case.

A retrospective, multicenter study of 1,207 women treated for non-metastatic breast cancer who then became pregnant showed that these survivors faced no greater risk of recurrence or death than their counterparts who underwent treatment but did not become pregnant.

This was true even for women treated for estrogen receptor (ER)-positive disease, news that may assuage a common concern that pregnancy hormones could stimulate the growth of any estrogen-fueled cancer cells left in the body after treatment. Pregnancy after ER-positive breast cancer is also sometimes discouraged because it requires survivors to temporarily stop taking postsurgical hormonal therapy that is meant to prevent recurrence. That therapy typically continues for 5 to 10 years.

To date, its authors say, the study was the largest investigation of the effects of post–breast cancer pregnancy on recurrence risk and the first to consider the issue in women treated for the most common subtype, ER-positive disease. The findings were presented in a June 3 press briefing during the 2017 ASCO Annual Meeting.

“Our findings confirm that pregnancy after breast cancer should not be discouraged, even for women with ER-positive cancer,” said lead study author Matteo Lambertini, M.D., a medical oncologist and ESMO fellow at the Institut Jules Bordet in Brussels, Belgium. “However, when deciding how long to wait before becoming pregnant, patients and doctors should consider each woman’s personal risk for recurrence, particularly for women who need adjuvant hormone therapy.”

The news, which Lambertini said “should serve as a strong basis for counseling women inquiring into the safety of future conception,” could be life-changing for those who have undergone treatment for breast cancer and are in their reproductive years. Breast cancer is the most common oncologic disease in women of this age group, and while 40 percent to 50 percent of young women diagnosed with the disease report that they want to have children, less than 10 percent become pregnant after treatment, in part because of recurrence concerns, Lambertini said. Of all survivors of cancer, those treated for breast cancer are the least likely to have children after diagnosis, ASCO added.

“These data provide reassurance to breast cancer survivors that having a baby after a breast cancer diagnosis may not increase the chance of their cancer coming back. For many young women around the world who want to grow and expand their families, it’s very comforting news,” said ASCO Expert Erica L. Mayer, M.D., M.P.H.

Previously, the investigators conducted a study that showed no detrimental effect of pregnancy on breast cancer recurrence risk within the first five years following conception; this latest study provides follow-up data out to a median 12.5 years past conception, important because survivors of ER-positive disease face a risk of recurrence that exceeds five years, Lambertini said.

Talk about this article with other patients, caregivers, and advocates in the Breast Cancer CURE discussion group.
CURE wants to hear from you! We are inviting you to Share Your Story with the readers of CURE. Submit your personal experience with cancer by visiting Share Your Story
Not yet receiving CURE in your mailbox? Sign up to receive CURE Magazine by visiting