Imagine facing a cancer diagnosis while pregnant. It's a terrifying prospect, forcing impossible choices between your own life and the health of your unborn child. The American Society of Clinical Oncology (ASCO) has just released new guidelines to help doctors navigate this incredibly complex situation, offering a framework for balancing the needs of both mother and fetus. This guidance, published in the Journal of Clinical Oncology, tackles some of the most difficult questions in cancer care during pregnancy. You can find the detailed guideline here: http://ascopubs.org/doi/full/10.1200/JCO-25-02115.
But here's where it gets controversial... How do you make decisions when the stakes are so high and the information is so limited?
"A new cancer diagnosis occurs in only about one in 1000–2000 pregnancies," explains Dr. Mikkael A. Sekeres, chief of the Division of Hematology at Sylvester Comprehensive Cancer Center in Miami, in an interview with Oncology News Central (ONC). (You can learn more about Dr. Sekeres here: https://doctors.umiamihealth.org/provider/mikkael-a-sekeres/1692745). "While it is a rare event, it has deep medical and psychosocial implications as we consider the needs of mother and fetus alike. Consequently, as we engage in shared decision-making with a pregnant patient with cancer, we need to consider the aggressiveness of the cancer, the toxicity of cancer diagnosis and staging (including imaging studies), optimizing therapy, and most importantly, patient goals." In essence, it's a high-wire act requiring careful consideration of all factors. The guideline provides evidence-based recommendations for diagnosis, treatment of new and recurring cancers, and obstetrical management that goes beyond standard pregnancy care.
And this is the part most people miss... The guidelines acknowledge the significant limitations in the available data. Much of the evidence supporting the recommendations comes from retrospective studies, case series, and individual case reports. While these provide valuable real-world insights, they aren't as robust as large, randomized controlled trials (which are, understandably, difficult to conduct in pregnant women with cancer). Despite the lower quality of evidence, the guideline authors stand by their recommendations, emphasizing that they offer crucial guidance for clinical practice in this challenging area.
So, what are the key considerations when balancing cancer treatment with fetal safety? Dr. Ann H. Partridge, director of the Adult Survivorship Program and cofounder and director of the Program for Young Adults with Breast Cancer at Dana-Farber Cancer Institute in Boston, shared her insights with ONC. (You can find her profile here: https://www.dana-farber.org/find-a-doctor/ann-h-partridge). According to Dr. Partridge, the most important aspects are: "1) understanding the patient’s preferences with regard to maintaining the pregnancy or not, as well as the options medically/socially regarding this part of the decision; 2) weighing the risks of the disease and the treatment options for the patient; and 3) considering the risks to the fetus with optimal therapy, risks to the fetus from the patient not receiving optimal therapy, and considerations of options for modifications of optimal therapy to mitigate risks to the fetus that would not necessarily worsen things for the patient.” In short, it's about aligning treatment with the patient's values and carefully weighing the potential harms and benefits for both mother and child.
"When considering all of this, it is also important to be frank and upfront about what we know and what we don’t know both from a data standpoint and for an individual patient or pregnancy," Dr. Partridge added. Transparency is paramount.
Key recommendations from the ASCO guideline include the importance of a multidisciplinary team—including pharmacists—to develop and adjust treatment plans. Why pharmacists? Because they play a crucial role in understanding drug interactions and potential side effects, especially important when considering the developing fetus. The guideline also emphasizes the need for informed consent, ensuring that patients and their caregivers fully understand the risks and benefits of any treatment. Patient autonomy and personal preferences are paramount, but the guideline also acknowledges that cancer can sometimes necessitate immediate, life-saving treatment, potentially requiring termination of the pregnancy. This is undoubtedly one of the most difficult and emotionally charged aspects of the guidance.
The guideline provides extensive details on diagnostic evaluation, including imaging (which needs careful consideration to minimize radiation exposure to the fetus), biopsies, survival outcomes, and systemic therapies like chemotherapy and targeted drugs.
One of the most challenging aspects for doctors and patients is the use of medications with unknown teratogenic potential – meaning their potential to cause birth defects. "Evidence informing recommendations for the diagnosis, oncologic management, and obstetrical management of pregnant patients with cancer is mostly based on retrospective observational studies, case series, and individual case reports," Dr. Sekeres points out. These types of studies, while valuable, are inherently limited.
"While these study designs offer valuable insights into a relatively rare and complex patient population, they are nevertheless inherently limited by potential bias, small sample sizes, and heterogeneity in study populations and treatment protocols," he adds. "Newer therapies are no different: Pregnant patients are almost uniformly excluded from trials leading to drug registration. As a result, we often try to delay therapy with these agents until patients have delivered or turn to alternatives where there is a modicum of data.” This lack of data creates a significant dilemma for clinicians.
Asked whether the teratogenic properties of newer therapies like bispecific antibodies or antibody-drug conjugates are well understood, Dr. Partridge responded, “No, these risks are not well understood at all, though there are biologic plausibility reasons to be concerned, and this is a challenging area to study.” This highlights the considerable uncertainty surrounding the use of these cutting-edge treatments during pregnancy.
Dr. Sekeres is an associate editor for the Journal of Clinical Oncology but was recused from any involvement in the peer review of this specific manuscript due to journal policy. He reported consulting or advisory roles with Kurome Therapeutics, Bristol Myers Squibb/Celgene, Agios, AstraZeneca, and Geron, and institutional research funding from Takeda, Bristol Myers Squibb, and Rigel. Dr. Partridge reported royalties from Wolters Kluwer for her authorship with UpToDate.
What do you think about the challenges of treating cancer during pregnancy? Should the focus always be on preserving the pregnancy, or are there situations where termination is the most ethical option? How comfortable would you be making these decisions with limited data on newer therapies? Share your thoughts and opinions in the comments below. This is a complex issue with no easy answers, and your perspective is valuable.
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