Colorectal cancer in the setting of pregnancy and familial risk

Gastrointestinal malignancies in pregnancy

Gastrointestinal malignancies, though uncommon in pregnancy, present several unique challenges with regards to diagnosis, staging, and treatment. Imaging the pregnant patient with a suspected or confirmed GI malignancy requires modifications to the radiologic modality of choice and protocol in order to minimize harm to the fetus, ensure accuracy in diagnosis and staging and guide treatment decisions. In this review article, we discuss the imaging approach to the pregnant patient with GI cancer, including safe radiologic modalities and modifications to imaging protocols. We also review the most common GI cancers encountered in pregnancy, including colorectal, pancreatic, gastric, and small bowel tumors, with emphasis to imaging findings, staging, and treatment considerations.

Imaging Cancer in Pregnancy

Pregnancy-associated cancer (PAC) is defined as cancer that is detected during pregnancy and up to 1 year postpartum. Although rare (~1:1000 pregnancies), PAC is increasing owing to postponed childbearing and advanced maternal age at conception. Cancer-related symptoms masked by physiologic gestational changes may delay diagnosis. Imaging, clinical management, and treatment require a carefully choreographed multidisciplinary team approach. The risk-benefit of every imaging modality, the strategies to balance the safety of mother and fetus, and the support of the patient and family at every step are crucial. US and MRI are preferred imaging modalities that lack ionizing radiation. Radiation dose concerns should be addressed, noting that most imaging examinations (including mammography, radiography, CT, and technetium 99m-labeled sulfur colloid sentinel lymph node staging) are performed at radiation levels below thresholds at which deterministic side effects are seen. Dose estimates should be provided after each examination. The use of iodinated intravenous contrast material is safe during pregnancy, but gadolinium-based contrast material should be avoided. Accurate diagnosis and staging combined with gestational age affect decisions about surgery and chemotherapy. Whole-body MRI with diffusion-weighted sequences is ideal to screen for primary and metastatic sites, determine disease stage, identify biopsy targets, and guide further cancer site-specific imaging. The authors provide an update of the imaging triage, safety considerations, cancer-specific imaging, and treatment options for cancer in pregnancy. An invited commentary by Silverstein and Van Loon is available online. Online supplemental material is available for this article. ^©RSNA, 2022.