Abnormal Prenatal Blood Test Results Could Indicate Hidden Maternal Cancers

Image: The study found previously undetected cancers in pregnant women with abnormal prenatal cfDNA test results (Photo courtesy of NIH)

Researchers have discovered previously undiagnosed cancers in 48.6% of pregnant individuals who received abnormal results from prenatal cell-free DNA (cfDNA) testing, which is typically used to screen for chromosomal disorders in the fetus. The types of cancers found included colorectal, breast, lung, and pancreatic cancers, as well as lymphoma, cholangiocarcinoma, and renal carcinoma. The cfDNA screening test analyzes placental DNA fragments circulating in the maternal bloodstream to identify an extra chromosome or determine the baby’s sex. In addition to detecting fetal DNA, cfDNA testing also identifies DNA released from the mother’s red blood stem cells, and occasionally, it can reveal abnormal DNA that may indicate an undiagnosed cancer in an asymptomatic pregnant individual. This study was published in the New England Journal of Medicine.

The ongoing IDENTIFY study by the National Institutes of Health (NIH, Bethesda, MD, USA) is investigating the implications of abnormal cfDNA test results that may suggest the presence of cancer. For the current analysis, the researchers screened 107 participants from the IDENTIFY study for cancer using whole-body magnetic resonance imaging (MRI), standard medical diagnostic tests, and cfDNA sequencing. Out of these participants, 52 were diagnosed with cancer. The researchers found that whole-body MRI was the most effective method for detecting cancer in this group.

Traditional diagnostic methods, such as reviewing medical history, assessing symptoms, and performing physical examinations, proved limited in detecting cancer or pinpointing its location. Other abnormal cfDNA results were found to be related to fibroids (benign tumors of the uterus), discrepancies between placental and fetal chromosomes, and clonal hematopoiesis in the mother (a precursor to blood cancers). The researchers emphasized the need for further studies to confirm the cfDNA sequencing patterns identified in this study, which could help detect cancer in pregnant individuals with no obvious clinical symptoms.