Is it safe for a pregnant woman to get surgery for cancer? If so, when? What about radiation and chemotherapy?
These are all questions addressed in newly released guidelines for the management of cancer during pregnancy from the American Society of Clinical Oncology (ASCO). Among the cancer experts who helped put the publication together is Nicole Christian, MD, associate professor of surgical oncology in the University of Colorado Anschutz Department of Surgery.
“It's a challenging clinical situation, because there are treatments and diagnostic workups that may pose a threat to the fetus, but undertreating a cancer also poses a threat to the mother,” says Christian, also a member of the CU Cancer Center. “ASCO wanted to offer this expert opinion because there aren’t many randomized controlled trials looking at pregnancy. It's a high-risk, vulnerable population.”
The ASCO publication notes that a new cancer diagnosis occurs in approximately one in 1,000-2,000 pregnancies, the majority being breast cancer and cervical cancer.
CU is recognized nationally for its treatment of young women with breast cancer and the ways in which pregnancy affects cancer risk, but the ASCO guidelines go beyond breast cancer to describe treatment for all cancer types.
“Pregnancy is very hormonally driven, and many cancers are very hormonally driven,” Christian says. “In some ways, pregnancy can be protective against cancer and in other ways, pregnancy can be a cancer risk. It's a very complicated dynamic of how pregnancy interacts with cancer risk.”
ASCO recommends that cancer in pregnant women be treated by an experienced multidisciplinary team, bringing a surgeon into the process early to determine if surgery is an option and how it can be performed safely.
Because surgery is a local treatment to a specific area of the body, Christian says, it poses less risk than a systemic therapy like chemotherapy, which presents exposure to the fetus.
“While there is a risk of surgery during pregnancy, surgery is actually one of the lowest-risk treatments for cancer,” Christian says. “There are chemotherapies that can be given during pregnancy, but they come with risks to the pregnancy. We routinely operate on pregnant women, and these guidelines include how to perform surgery safely.”
Because many imaging tests for cancer — including mammograms — involve radiation, oncologists must be careful when conducting imaging on pregnant women. The imaging section of the ASCO guidelines encourage limiting radiation exposure to the fetus as much as possible.
“In breast cancer, as an example, mammograms are something that would not be part of our initial diagnostic plan,” Christian says. “But after you've had a diagnosis of breast cancer, which could be diagnosed with an ultrasound and a biopsy that pose no risk to the fetus, that might be something that we have a conversation with the patient about. If we feel a mammogram is necessary to come up with the treatment plan, we can shield the fetus. We can do the minimum number of views necessary to get the information that we need.”
The ASCO guidelines also offer advice on breastfeeding during and after cancer treatment, with a focus on breast cancer and women who receive a single or double mastectomy.
“Obviously, after a mastectomy, women cannot breastfeed from that breast,” Christian says. “If they keep their other breast, they would be able to breastfeed on that side. There are chemotherapies that frequently are given after the woman gives birth that go into breast milk, so breastfeeding sometimes isn't an option for women who are being treated for cancer. There are women who are able to successfully breastfeed after treatment of cancer, but that is part of the informed consent as to what the risks and benefits are of being treated for cancer while pregnant and then impact on lactation.”
Christian says that she and the other ASCO members who put the pregnancy guidelines together did so in large part because of the complexity of managing a mother’s health along with the health of the fetus.
“It can be a more complicated conversation, because you're not just thinking about the patient and how to treat the patient with breast cancer — you have to take into consideration the pregnancy and the health of the fetus,” Christian says. “In a lot of cancer care, you're already doing a lot of shared decision-making about the risks and benefits of any intervention or approach.
“Cancer can be an incredibly devastating diagnosis, but for patients who are pregnant, it can add an extra layer of devastation,” she continues. “A lot of what we talk about in the guidelines are best practices around communication and patient access — how do you add recognition of this extra layer that makes it really challenging?”