Could Your Prenatal Test Uncover Hidden Cancer? New Study Shows Surprising Results

Hidden Maternal Cancer Revealed Through Common Prenatal DNA Test: A New Discovery

Prenatal genetic screening has become a staple in modern obstetric care, providing invaluable information about a developing fetus, particularly in identifying chromosomal abnormalities and genetic disorders such as Down syndrome. However, a recent study has uncovered a surprising secondary benefit of these tests: the ability to detect undiagnosed cancers in the pregnant individual. This unexpected finding has sparked conversations about integrating cancer screening into routine prenatal care, raising the potential to catch cancers that would otherwise go unnoticed.

The study, conducted by a team of researchers from the National Institutes of Health, found that a common prenatal test, known as cell-free DNA (cfDNA) testing, which is typically used to detect fetal abnormalities, may also reveal signs of hidden cancers in pregnant individuals. In cases where cfDNA results were difficult to interpret, nearly half of the patients were diagnosed with previously undetected cancer. The findings suggest that pregnant individuals, particularly those with abnormal cfDNA results, may benefit from further investigation, such as whole-body imaging or other diagnostic methods, to ensure that potential cancer is not overlooked.

What is cfDNA Testing and How Does It Work?

Cell-free DNA testing is a non-invasive method that allows clinicians to assess the genetic material of a fetus without the need for more invasive procedures like amniocentesis. The test works by analyzing small DNA fragments that are released into the bloodstream from both the fetus and the pregnant individual. While a large portion of the cfDNA comes from the mother (about 90%), the remaining 10% is from the placenta, which provides information about the developing fetus. This method has become widely used to detect chromosomal abnormalities such as trisomy 21 (Down syndrome) in early pregnancy, but recent studies have raised the question of whether cfDNA tests can also be useful for identifying cancers in the pregnant individual carrying the child.

Cancer cells, much like fetal cells, release DNA into the bloodstream. In particular, certain types of cancers—especially blood cancers and tumors—can produce abnormal cfDNA patterns that might show up on prenatal screenings. Although this discovery is still in the early stages, it raises the possibility that cfDNA could serve as a tool for detecting undiagnosed cancers, especially in cases where no other symptoms are apparent.

Study Overview: How Researchers Found Cancer Through Prenatal Testing

The study analyzed 107 pregnant individuals who underwent prenatal cfDNA testing between December 2019 and December 2023. All participants had received abnormal cfDNA results that were difficult to interpret as signs of a fetal abnormality. These puzzling results led the researchers to further investigate the patients using imaging techniques such as magnetic resonance imaging (MRI) and additional diagnostic tests.

The results were surprising: 52 of the 107 patients were found to have previously undiagnosed cancers. Of these, 32 had blood cancers, with 31 diagnosed with lymphoma, and 20 had solid tumors. Among the tumors identified, one patient had a grapefruit-sized growth, while two others were diagnosed with rare bile duct cancers. These findings highlight the potential for prenatal cfDNA tests to reveal life-threatening conditions in the mother that might have otherwise gone unnoticed.

Perhaps more concerning was the fact that 29 of the patients diagnosed with cancer were asymptomatic, meaning they exhibited no noticeable symptoms. Another 13 patients had cancer symptoms, but these were mistakenly attributed to pregnancy, such as fatigue or abdominal discomfort. Ten other patients either failed to recognize their symptoms or received false reassurance after being tested, allowing their cancers to go undetected.

The Role of MRI in Cancer Detection

MRI scans emerged as the most effective method for detecting cancers in the study. While traditional diagnostic methods, including physical examinations and patient history reviews, proved to be of limited utility, MRI scans were able to identify cancers that had eluded other forms of screening. This supports the idea that MRI could be an essential tool in the evaluation of pregnant individuals who receive abnormal cfDNA results suggestive of cancer.

MRI has the advantage of being a non-invasive imaging technique that provides detailed, high-resolution images of the body. It can detect tumors, lymph node enlargement, and other signs of cancer with high accuracy, making it an invaluable diagnostic tool for uncovering hidden cancers. In the case of the study, MRI scans were able to identify the cancers that were missed by standard methods, which emphasizes the need for more thorough investigations when unusual prenatal test results are encountered.

Cancer Detection and Pregnancy: A Delicate Balance

The findings of this study are significant but should not cause alarm. The vast majority of pregnancies result in healthy outcomes, and most pregnant individuals who undergo cfDNA testing will not be diagnosed with cancer. However, the study does underscore the importance of paying attention to unusual results in prenatal screenings, particularly when these results are difficult to interpret. The fact that many of the cancers identified were asymptomatic or masked by pregnancy-related symptoms suggests that obstetricians should be more vigilant when reviewing cfDNA results and consider additional screenings, such as MRI, when necessary.

The researchers also emphasize that while the potential for detecting cancer through cfDNA testing is promising, it should not replace traditional cancer screenings or clinical evaluations. Rather, it should be viewed as an additional tool that can provide early warnings and prompt further investigation. This could be especially beneficial for high-risk individuals or those with a family history of cancer who may not have typical symptoms of the disease.

Implications for Future Prenatal Care

The discovery that prenatal cfDNA tests can potentially uncover undiagnosed cancers in pregnant individuals could have profound implications for prenatal care. If further studies confirm these findings, cfDNA testing could become an integral part of routine cancer screening during pregnancy. This would allow clinicians to catch cancers earlier and offer more timely interventions, leading to better outcomes for both the parent and the child.

Furthermore, the use of MRI as a follow-up diagnostic tool could improve the accuracy of cancer detection and ensure that those with hidden cancers receive the appropriate treatment as soon as possible. By incorporating cancer screening into prenatal care, doctors may be able to offer a more comprehensive approach to maternal health, addressing not only fetal well-being but also the overall health of the pregnant individual.

Study Reference: https://www.nejm.org/doi/full/10.1056/NEJMoa2401029

Conclusion

The findings of this study represent an exciting advancement in the field of prenatal care and cancer detection. While rare, the ability to identify hidden cancers through common prenatal testing could provide a crucial opportunity for early intervention, particularly in cases where symptoms are absent or misattributed to pregnancy. As more research is conducted in this area, it is likely that prenatal cfDNA testing will become an even more powerful tool, potentially saving lives by catching cancers before they reach an advanced stage.

For now, the key takeaway from this research is the need for heightened awareness and vigilance when interpreting prenatal test results. When confronted with abnormal cfDNA results, obstetricians should consider the possibility of underlying cancer and take appropriate steps to investigate further, including the use of MRI scans and other diagnostic tools. The integration of cancer screening into prenatal care could be the next major step forward in improving maternal health outcomes and saving lives.