New Research on Breast Cancer After Pregnancy

Last Updated: May 11, 2018

Dr. Daniel Hayes discusses new research on the risk of breast cancer recurrence after pregnancy from the 2017 ASCO Annual Meeting.


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Pregnancy After Breast Cancer Does Not Increase Chance of Recurrence

ASCO President Daniel F. Hayes, MD, FACP, FASCO: Being told you have breast cancer is, of course, a devastating thing to hear. We do a lot to help women, not just be cured of their breast cancer, but to live normal lives afterwards.

A quarter of women diagnosed with breast cancer are in the age of fertility: 35 to 50, but usually 30 to 45, and we have increasing evidence that it's okay to have a baby if you want to.

This is a question I get asked--I'm a breast cancer doctor--I get asked this very frequently. There are a number of technologies going on to help them have a baby, but nonetheless, the real issue is, will this increase the chances that my cancer might come back. It's a real concern. This study, which was actually started long ago, 15 years ago, or more, out of Europe, followed a group of women and kept track of whether they got pregnant or not.

We'll never do a study where half get pregnant, and half don't, that's not on the table, so we have to look at how women elected to do it or not. And what they've reported already, many years ago, with relatively short follow-up, is that the women who elected to get pregnant and have a baby, seemed to be doing just as well as those who didn't.

This is now with longer follow-up, over 12 years, almost 13 years of follow-up, and it suggests again, that the women who elected to get pregnant did just as well as the women who didn't. And one group of patients maybe even better. That's hard to believe. Probably, it's what's called a survivor bias, is that the women who decided to get pregnant were the ones who were doing better anyway.

One issue, though is things have changed in our treatment of breast cancer, especially women whose cancer is positive for the estrogen receptor, and we put those women on anti-estrogen therapy that really reduces the odds of recurrence and mortality. And we treat them for years now: 5, 10, even 15 years. The issue is, is it safe to stop that, wait for it to wash out, get pregnant, have your baby, and then start up again? We don't know that, and so this same group has started a trial that's being run all over the world--my own institution is part of it, the sun never sets on this trial--in which we're asking exactly that question.

So for young women who get breast cancer and who wish to get pregnant, we say great, stop your anti-estrogen therapy, we follow them along for two years, or whatever it takes for them to get pregnant and deliver, and then they start it up again. That trial could not have been done if this trial hadn't been done, this study hadn't been done first, suggesting it's probably safe to do that, and we're not sure, so this asks the question.

They will cause you trouble, they will go to college, they cost you a lot of money, but I've just had my first grand-daughter, and they're clearly worth it.

[Closing and Credits]

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