Treating Breast Cancer During Pregnancy Calls for Careful Timing of Therapies and Sensitive Discussions With Patients

A Conversation With Carey K. Anders, MD


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Carey K. Anders, MD

Carey K. Anders, MD

Breast cancer during pregnancy is relatively uncommon; however, it poses a significant clinical challenge to the patient and her multidisciplinary care team. To shed light on this difficult issue, The ASCO Post spoke with Carey K. Anders, MD, a medical oncologist and researcher at the University of North Carolina Comprehensive Cancer Center. Dr. Anders’ clinical interest is breast cancer, specifically breast cancer arising in younger women who have developed brain metastases. Dr. Anders and her colleagues recently investigated the multidisciplinary management of breast cancer during pregnancy. 

Treatment Considerations 

How does the treatment approach to breast cancer change during pregnancy? 

The most important factor to consider is the specific trimester of the pregnancy when the woman is diagnosed with breast cancer. So, the first trimester is from conception to about the 13th week. That is a very critical time in the pregnancy for organogenesis as well as a high-risk time for spontaneous miscarriage. 

To ensure the safety of the pregnancy, systemic treatment (chemotherapy, biologics, and endocrine therapy) is contraindicated during the first trimester, and radiation therapy, as a second modality, is contraindicated during the full course of pregnancy. We also try to limit any surgical interventions until the patient is in the second trimester. There are, however, circumstances in the first trimester where surgery may be permitted. 

Literature Review 

Please describe the methodology behind your recently published study of breast cancer during pregnancy. 

We conducted a comprehensive review of targeted literature regarding multidisciplinary therapeutic approaches to breast cancer during pregnancy.1 We specifically looked at the trials that were most pertinent to this clinical setting. 

My colleague, Dr. Shlomit Shachar, who is a medical oncologist at Rambam Health Care Campus in Israel, did extensive searches on PubMed using search terms that would lead us to the best trials that have looked at breast cancer during pregnancy. Along with studies of medical, surgical, and radiation oncology techniques, supportive care and imaging approaches were also reviewed. 

Role of Imaging 

How does imaging play a role in this challenging clinical setting? 

When you have a patient diagnosed with breast cancer, much of the treatment depends on the stage of the disease, which is largely determined by computed tomography, bone scan, and, if necessary, a brain magnetic resonance imaging scan. Unfortunately, many of our radioisotopic imaging modalities, as well as some of the dyes that are used, are contraindicated during pregnancy. However, there are ways to adequately stage a patient without putting the pregnancy at risk. 

“At a young age, these women are suddenly faced with two life-changing events, so it is vital for the oncologist to be aware of their psychological needs.”
— Carey K. Anders, MD

Ultrasound can differentiate between solid and cystic lesions and does not entail ionizing radiation, which may be associated with birth defects. For instance, we can perform an ultrasound of the abdomen, particularly the liver, in an effort to determine whether the patient has metastatic disease. Mammography is also helpful in determining the extent of disease by visualizing suspicious microcalcifications and by also evaluating the contralateral breast. Yet, due to changes in the breast tissue associated with pregnancy, mammography has limitations. 

Chemotherapy Issues 

Please talk a bit about the use of chemotherapy in women with breast cancer who are pregnant. 

As mentioned, chemotherapy is contraindicated during the patient’s first trimester. Once we pass that critical stage of pregnancy, we do have guidance on the administration of chemotherapy, most of it out of The University of Texas MD Anderson Cancer Center. 

Essentially, we have new safety data for anthracycline-based chemotherapy, and we tend to administer that treatment past week 13 but will probably halt it within the 34th or 35th week, because we do not want the patient to be in hematologic nadir nearing the time of potential delivery. By that point, we are careful about any chemotherapy-induced side effects that might compromise delivery. That said, data on the use of supportive care drugs such as antiemetics and growth factors during pregnancy are fairly limited. 

Doctor-Patient Discussions 

Please share your thoughts about doctor-patient discussions during this trying time, when a pregnant woman is also facing a life-threatening disease. 

Naturally, it is a time of great vulnerability. Many of the patients I’ve treated received the news that they were pregnant and that they had breast cancer concurrently, because they had taken a pregnancy test earlier and were going in for a radiographic imaging scan. At a young age, these women are suddenly faced with two life-changing events, so it is vital for the oncologist to be aware of their psychological needs. And it’s important to talk about safety concerns for the pregnancy, referencing solid data from the literature. 

The other critical component is for the oncologist to have a solid relationship with the maternal-fetal medicine team. With my patients, I’ve found that regular ultrasounds give them a sense of security about the health and development of the fetus. This is especially critical for high-risk patients. It is also important to note that an ongoing informed decision-making process should be integrated into the care of pregnant women with breast cancer. ■ 

DISCLOSURE: Dr. Anders has received research funding from Novartis, Sanofi, toBBB, GERON, Angiochem, Merrimack, PUMA, Lily, Merck, Oncothyreon, Cascadian, Nektar, and Tesaro; is an uncompensated advisor for Novartis, Sanofi, toBBB, Geron, Angiochem, Merrimack, Lily, Genentech, Nektar, and Kadmon; and has received royalties from UpToDate and Jones and Bartlett. 

REFERENCE 

1. Shachar SS, Gallagher K, McGuire K, et al: Multidisciplinary management of breast cancer during pregnancy. Oncologist 22:324-334, 2017.



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