How a Routine Prenatal Test Can Detect Hidden Maternal Cancer
A DNA test designed to screen for fetal abnormalities can sometimes uncover unexpected findings, including hidden cancer in the pregnant individual.
A recent analysis revealed that cell-free DNA (cfDNA) screening, commonly used to detect chromosomal disorders, has the potential to identify undiagnosed cancers. Among patients whose cfDNA test results were ambiguous, nearly half were found to have cancer.
To clarify, the study specifically focused on individuals with difficult-to-interpret test results. Consequently, those diagnosed with cancer represented a very small subset of all pregnant people undergoing cfDNA screening. However, many of these patients had no symptoms or displayed symptoms initially attributed to pregnancy, underscoring the importance of enhanced cancer screening and vigilance in obstetric care.
“Our findings support the use of whole-body MRI to evaluate pregnant individuals with prenatal cfDNA results suggestive of cancer,” explained Amy Turriff, a geneticist at the National Institutes of Health, and her team. They also highlighted the need for further research into cfDNA sequencing patterns to better identify patients at risk for cancer.
The cfDNA test examines fragments of DNA from the placenta, which circulate in the bloodstream of the pregnant individual. Around 10% of the circulating cfDNA comes from the placenta, while the remaining 90% is maternal. This non-invasive test is widely used to detect chromosomal abnormalities in fetuses, avoiding the risks of invasive procedures like amniocentesis.
Routine Prenatal cfDNA Screening May Help Detect Undiagnosed Cancers, Study Finds
Interestingly, prior studies have shown that cancer patients can exhibit unusual cfDNA signatures. In some cases, abnormal prenatal cfDNA test results have directly led to cancer diagnoses. Turriff’s team sought to investigate whether routine prenatal cfDNA screening could consistently identify undiagnosed cancers.
The study involved 107 pregnant individuals with abnormal cfDNA results that didn’t indicate clear fetal abnormalities. Between December 2019 and December 2023, MRI and other diagnostic tests revealed that 52 had undiagnosed cancers, including 32 blood cancers (31 lymphomas) and 20 solid tumors. Some cases were severe, such as one with a grapefruit-sized tumor and two with rare bile duct cancers. MRI was the most effective diagnostic tool, surpassing physical exams and patient history.
Among the 52 cancer patients, 29 were asymptomatic, 13 had symptoms linked to pregnancy, and 10 either overlooked their symptoms or had inconclusive evaluations. The 55 participants without cancer most commonly had uterine fibroids, detectable by MRI.
A similar 2022 study in the Netherlands supported these findings. While rare, the results stress the need for cancer screening in ambiguous cfDNA results, especially since many patients were asymptomatic or had symptoms dismissed. Routine MRI scans should be considered when cfDNA results are unclear.
Read Original Article: Science Alert
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