Although rare, affecting about one in 1,000 pregnant women, the prevalence of pregnancy-associated cancer (PAC) is rising, a result of postponed childbearing and older maternal age at conception.
Javitt
PAC is defined as any cancer detected during pregnancy and up to one year postpartum. The most common PACs are breast cancer, lymphoma, uterine cervical cancer, leukemia and ovarian cancer.
“Pregnancy-associated cancer is one of the most difficult and stressful clinical scenarios for the patient, her family and the medical team caring for them,” said Marcia Javitt, MD, an adjunct professor of radiology at the George Washington University Medical Center. “Imaging, clinical management and treatment require a carefully choreographed, multidisciplinary team approach.”
Dr. Javitt, who co-authored a recent RadioGraphics article on imaging cancer in pregnancy, made her remarks during a Monday session.
Weighing Fetal Risks With Maternal Benefits
Imaging and management of PAC requires weighing fetal risks with maternal benefits.
“The risk-benefit of every imaging modality, the strategies to balance the safety of the mother and fetus, and the support of the patient and family at every step are crucial,” Dr. Javitt said.
As Dr. Javitt explained, imaging modalities should be selected for safety and personalized care according to the primary cancer site, gestational age and tumor biology. As such, US and MRI are the generally preferred imaging modalities due to their lack of ionizing radiation.
While in some cases imaging with ionizing radiation may be entertained after accounting for gestational age, Dr. Javitt cautioned that radiation dose concerns must be addressed in advance of these studies and reviewed after each examination. She also explained that abdominal shielding is usually not recommended during pregnancy because most of the dose to the uterus and fetus is from internal scatter.
However, studies such as mammography or radiography outside the abdominopelvic cavity may be performed selectively for urgent concerns as they have negligible exposure to the uterus and fetus.
Furthermore, CT ionizing radiation may be required for life-threatening conditions such as trauma or suspected pulmonary embolism during pregnancy.
“In general, intravenous iodinated contrast material should be avoided in pregnancy because the iodine content of contrast media has the potential to produce neonatal hypothyroidism,” Dr. Javitt said. “Gadolinium-based contrast material should also be avoided because of teratogenic effects seen in animal studies.”
Radiology Is Essential For Detecting Pregnancy-Associated Cancer
Cancer-related signs and symptoms of PAC are often masked by physiologic gestational challenges that can delay diagnosis. According to Dr. Javitt, this is problematic because early and accurate diagnosis has a direct impact on management decisions and treatment options such as surgery and chemotherapy.
“Radiology is essential for cancer detection, determining gestational age, image-guided biopsy, staging, monitoring treatment response and overseeing follow-up,” Dr. Javitt explained.
Dr. Javitt recommends the use of whole-body MRI with diffusion-weighted sequences to screen for primary and metastatic sites, determine disease stage, identify biopsy targets, and guide further cancer site-specific imaging.
“To date, there is no evidence in the peer-reviewed medical literature of harm to the fetus from MRI performed at 1.5T or 3T field strengths,” Dr. Javitt added.
Keeping Patients Informed
According to Dr. Javitt, a key takeaway is that radiologists play a central role in optimizing the treatment of pregnancy-related cancer.
“A multidisciplinary team, including the radiologist, should counsel the patient about safe and effective diagnostic testing followed by informed treatment selection for both the mother and fetus,” she concluded. “Doing so may prevent delays that threaten maternal and fetal well-being.”
Access the presentation, “Imaging Considerations in Challenging Populations,” (M4-CMS01) on demand at Meeting.RSNA.org.
Does your radiology department have guidelines in place for imaging obese, elderly, pediatric and pregnant patients? #RSNA22
— RSNA (@RSNA) November 28, 2022
