PracticeUpdate Oncology May 2019

EXPERT OPINION 18

Breast Cancer During Pregnancy Interview with Jennifer Litton MD by Tyeese L. Gaines DO

Dr. Litton is Associate Professor in the Department of Breast Medical Oncology, Division of Cancer Medicine at The University of Texas M.D. Anderson Cancer Center in Houston, Texas.

mastectomy, but in fact, we saw no differ- ence in outcome or side effects with either breast-conserving surgery versus mastec- tomy. We also, though, have to take into account when radiation can be given. That really does need to be delayed until after delivery, and a lot of times because of these multi-modality therapies, we are able to bridge. In fact, in our group in MD Ander- son, we’ve been treating women since the '80s with chemotherapy during pregnancy. Our median gestational age is 37 weeks, so a lot of times we can get women to where they would naturally deliver and then con- tinue the therapy after. Dr. Gaines: What about delaying breast cancer treatment until after delivery? Is that a safe and reasonable option? Dr. Litton: Well, we do show that if you have significant delays in your therapy, espe- cially remember these are young women with often much more aggressive tumors, we do see worse outcomes and if you look back at the older case reports, right. We can’t have randomized trials in this just as well as the breast cancer patient who’s not pregnant. And I think that that is the important aspect, to go ahead and treat in the second and third trimester. " " …if you give standard-of-care chemotherapy in the second and third trimester, you do

Dr. Gaines: How common is breast cancer during pregnancy? Dr. Litton: Well, at some estimates, it was in about 1 of 3000 pregnancies. It’s very hard to track this exactly because a lot of times it didn’t get reported over several decades, but I think now that treating cancer during pregnancy has become much more stand- ard of care, we are seeing more patients in all of our practices. The other thing is, is that as women are delaying childbearing now into their 30s and 40s with repro- ductive technologies, we are seeing the intersection more, and that’s actually been tracked in some countries. Dr. Gaines: So, what are some of the unique considerations that you have to take into account when you are approaching treating breast cancer in a patient who’s pregnant? Dr. Litton: Well, I think one of the first things is that we actually have to diagnose it appro- priately. Any lump during pregnancy that stays there 2 weeks should be investigated and not just assumed to be a part of the change in the breast from the pregnan- cies. There was a concern decades ago that if you took a core biopsy, you would cause a milk fistula, and so a lot of patients went undiagnosed. I have yet to see that and I have treated over 100 breast cancer patients during pregnancy. So we need to do a core biopsy just like we would do in a non-pregnant patient so we can under- stand the biology. You need to look at ER, PR, and HER2. With regards to imaging, we do need to do imaging in the pregnant patient with breast cancer.

We can do a mammogram with fetal shield- ing. It is similar to radiation as to a long flight. We often do MRIs without contrast if we do feel that we need to look for cancer in other places, ultrasounds if needed. And then for treatment, the big thing is that we do need to wait until the second or third trimester. We know that if we give chemotherapy in the first trimester that the risk of birth defects can be anywhere from 15% to 20% or higher, yet if we wait until the second and third trimester, that the risk of birth defects are very similar to what they are in just the general population. Dr. Gaines: So, how does pregnancy change the treatment plan for, say, localized breast cancer? Dr. Litton: Right. Absolutely. So first of all, a lot of these women are very young. The tum- ors are often tumors that we need to give chemotherapy for. So for those patients, we do. We give the same chemo we would give to our non-pregnant patients up front, either AC or FAC, and we can give weekly Taxol as well. The one thing we cannot give is the anti-HER2 agents, trastuzumab and pertuzumab. We have done it once in an emergency situation for someone with met- astatic disease. It does require hydration because it can cause kidney failure in the fetus. But a lot of times we can start with the AC chemotherapy bridge to delivery and give effectively the anti-HER2 therapy after. We don’t give antiestrogen therapies dur- ing pregnancy. That also has a high risk of birth defects. As far as surgery, we looked at MD Anderson, and traditionally, women were told they could only get a

PRACTICEUPDATE ONCOLOGY