Limitations on a woman’s options when pregnant and diagnosed with cancer can directly impact her ability to save her own life and preserve her fertility for future pregnancies.
Current legislation limiting women’s reproductive rights in the United States have a significant impact on a woman's ability to make difficult, yet critical medical decisions when diagnosed with cancer while pregnant or when undergoing cancer therapy and becoming pregnant, explained Lisa M. Coussens, MD (hc), PhD, FAACR, chairwoman of the Department of Cell, Developmental and Cancer Biology and associate director for basic research in the Oregon Health & Science University Knight Cancer Institute in Portland, Oregon, during a presentation at the American Association for Cancer Research (AACR) Annual Meeting 2023.
“We're obviously speaking about something that is both timely and timeless. Cancer diagnosis during pregnancy is something that's happened ever since people were getting pregnant and getting cancer. It happens concurrently, and it's happened for a long time,” Anne Partridge, MD, vice chair of medical oncology at Dana Farber Cancer Institute in Boston, Massachusetts, said during the presentation. “It's coming to the forefront as a hot topic at this meeting in light of recent changes in the United States from a legal standpoint. It's been a problem, though, that's been faced around the world for a long time, and there are lots of data to inform how we think about this problem.”
Partridge noted that in order to better understand the landscape for cancer treatment during pregnancy, it’s important to assess how often patients are diagnosed with cancer while pregnant or how often patients become pregnant while undergoing cancer treatment. Additionally, it’s important to identify the patient populations in which this is most likely to occur.
“When we think about who's likely to be pregnant and diagnosed with a cancer, or diagnosed with a cancer and then get pregnant, it's important to know what disease groups you’re typically going to see in these patient populations,” Partridge said. “This is even more timely as we've recently seen clear evidence that there's an increased incidence of early onset cancer globally.”
Partridge explained that a recent publication led by investigators at the Harvard School of Public Health showed that in many of the solid tumors in which early onset is likely a factor, such as breast cancer, colon cancer, endometrial cancer, and other cancers associated with lifetime exposures to things like obesity, that's where there has been an increase in solid tumors. As more young onset cancers occur, there will also be a greater conflation of cancer during pregnancy, particularly for young onset cancers that affect women, according to Partridge.
The other issue that's occurring is changes in when people are first having their children. Partridge explained that data that is now over a decade old shows that the average age of first birth changed dramatically during a period of 30 years.
“The [first birth age in the] United States actually tends to be a little bit younger, on average, than in other developed countries. Yet we still have seen a change of about 5 years from the ‘70s to the early 2000s, and this is not expected to go away,” Partridge said. “Mind you, this is happening in less developed countries around the world where they don't have the same incidence of later onset cancers for lots of different reasons and illnesses, [where] the young adult population is the majority of their population they think about with certain solid tumors, including things like breast cancer.”
In the United States, the incidence of pregnancy-associated cancer tends to occur between the ages of 25 to 54 years. Additionally, this rate of incidence has gone up between 2002 and 2012, according to Partridge.
“If you look at a group from [age] 35 to 39 [years], cancer is happening in over 100 people per 100,000 pregnancies, and there's a lot of pregnancies every year in this country alone,” Patridge said. “As women get older, again, cancer typically is a disease of aging, you're going to see these 2 things coming together more and more. The current stats on this are about 1 in 1000 pregnancies will be complicated by a cancer.”
Partridge noted that, according to this data, the most common cancer diagnosis during pregnancy is breast cancer, although thyroid cancer is also quite high in terms of occurrence.
“Of course, the blood cancers—leukemia/lymphoma—have kind of special issues when presenting during pregnancy, especially because they tend to be more emergent,” Patridge said. “There isn't often time to wait.”
Additionally, Partridge noted that melanoma is also quite prevalent during pregnancy. Fortunately, the vast majority of cases of melanoma during pregnancy are very early stage and don't seem to present the same kinds of problems, according to Partridge. However, there have been predictions in the field that there will be an increasing number of cases of melanoma occurring during pregnancy because of present environmental issues.
Partridge noted there are also certain challenges related to data collection in terms of classification of patients in much of the clinical research conducted on cancer occurrence during pregnancy.
“When we look at these literature, and this is especially true in the breast cancer populations, investigators often put ‘pregnancy during cancer treatment’ or ‘cancer during pregnancy’ and ‘cancer after pregnancy developing’ together—they're conflating the ‘postpartum’ with the ‘during the pregnancy’ diagnoses,” Partridge said. “That's useful, I guess, to get big numbers. It's not at all useful when we're talking about treating people during or managing people during a pregnancy.”
Partridge explained further that of the women diagnosed during pregnancy with cancer, the majority are diagnosed in the first trimester. Further, when thinking about the laws and the management of these patients in the modern day, this is an important statistic to remember.
“The big picture here is that pregnancy during a cancer diagnosis or cancer during a pregnancy poses complex therapeutic and ethical challenges. The mother is the beneficiary of treatment, and the fetus may be put at risk,” Partridge said. “Patient autonomy is the primary guiding principle, generally supporting what we all aspire to as clinicians—and that’s shared decision making, and that may be at odds with medical values in this setting in particular.”
Partridge noted that it remains important to remember that fetal wellbeing is often dependent on maternal wellbeing in certain settings in the short term and in many settings in the long term. Further, when trying to maintain a pregnancy, it is difficult to avoid some element of compromise when it comes to maternal wellbeing and fetal wellbeing.
“The other big problem when we're talking about this and trying to use data to inform our decisions is that there's a lack of randomized treatment data to support safety and efficacy of any standards here,” Partridge said. “There are small numbers, it's obviously ethically difficult to randomize in this setting, and there are very few prospective studies. Much of the data comes from case reports, observational cohorts, and retrospective analyses, which are of course subject to heterogeneous quality issues and biases.”
Effective management of patients with cancer during pregnancy often requires compromise such as modifying standard treatment algorithms or diagnostic algorithms, according to Partridge.
“The goal is to aim for the most effective treatment for the woman with cancer, and, at the same time, minimizing the risk for the fetus, which is something that can be almost impossible in some settings,” Partridge said. “Obviously, this entails consideration of the choices a woman may have with regard to whether or not she wants to keep the pregnancy and the priorities there.”
Partridge AH. A patient-centered, evidence-based approach to cancer during pregnancy. Presented at AACR Annual Meeting 2023; April 17, 2023. Accessed April 17, 2023. https://www.abstractsonline.com/pp8/#!/10828/session/60