Breast Cancer and Pregnancy: Expert Separates Fact From Fiction

Both breast cancer and pregnancy can cause a whirlwind of emotions for women. Put the two together, and the result can be downright overwhelming, says Hyman B. Muss.

By the numbers, how big of a problem is breast cancer during pregnancy?

What is the prognosis for a woman who is pregnant and has breast cancer?

In an interview with Muss, a professor of oncology at the University of North Carolina, CURE gained insight into the complications, misconceptions and likely outcomes of patients who are simultaneously pregnant and battling breast cancer.It’s very uncommon, fortunately, but it’s common enough that virtually all oncologists in practice or in major academic centers will see it at some point. I would say that a doctor in a large setting would probably see a few patients a year who have breast cancer and are pregnant.The average age of developing breast cancer is 61 in the United States, but these pregnant patients are obviously much younger. Some of these women may be born with a higher genetic risk of developing breast cancer — such as with BRCA1 or BRCA2 gene mutations — and might be more likely to have more aggressive tumors, like triple-negative disease.

What misconceptions exist about breast cancer treatment and pregnancy?

Also, women who are pregnant tend to present with a higher stage of breast cancer because it’s very hard to detect a breast mass when you’re pregnant. Your breasts are engorged and a tiny mass is going to be hard to detect. However, these women, if you compare them with the general population, tend to have a little higher stage, but most of the research shows that these women will have similar outcomes than older women with breast cancer when you adjust for the stage of the cancer, hormone enhancers, HER2 status and other biologic characteristics of the tumor.You certainly don’t have to terminate the pregnancy because you have breast cancer. You can really do a lot, in terms of treatment. Surgery is safe during breast cancer and you can screen people and do ultrasounds and you can even do a chest X-ray and put shielding on the patient to protect the fetus from the very tiny dose of radiation. Because a lot of these women have more aggressive tumors, it’s safe to do chemotherapy after the first trimester, which may sound surprising. By the time the woman is about 12 to 14 weeks along, all the organs are formed in the baby. Giving women chemotherapy after that first trimester — although it’s scary for everyone involved — is usually well-tolerated. We have good data that show the rate of fetal abnormalities is no higher than the background. The percentage is very small. We don’t have thousands of kids in this dataset, but we have hundreds of kids, and they’re doing well in school and don’t have any developmental lag.

As for what you can’t do during pregnancy, you can’t do things like radiation, but that’s usually not too compelling of a treatment option anyway. And you don’t want to use any hormone-blocking therapy, because that may interfere with the development of the fetus.

Treating patients with breast cancer who are pregnant is a team game. The OBGYN must work with the oncologist to provide the best outcome.