DNA testing to look for fetal abnormalities can produce some unexpected results.
According to a new analysis, a cell-free DNA test for diagnosing chromosomal disorders also reveals unknowns. Cancer In the person who carries the child. In a study of patients with equivocal results, about half had occult cancer.
To be perfectly clear: the study only analyzed pregnant women whose test results were difficult to interpret. Therefore, only a small percentage of all pregnant women go for cancer screening.
But a significant number of cancer patients had no symptoms or only symptoms caused by pregnancy, which means that a more rigorous cancer diagnosis and more attention to anything that seems unusual, is important during obstetrics.
"Our results support the use of the whole body MRI Evaluation of prenatal cfDNA sequence results suggestive of cancer in pregnant women". A group of researchers led by geneticist Amy Turriff wrote National Institutes of Health in the US.
"Further investigation of cfDNA-sequencing patterns may help identify subgroups of people with cancer who have unreported outcomes."
A Cell-free DNA test, or cfDNA, is a test of placental material found in a pregnant woman's blood. It can diagnose abnormal chromosome numbers in a safe way for both the parents and the fetus. The test detects fragments of damaged DNA without taking a sample from the uterus, as seen in invasive amniocentesis tests.
An unborn fetus is relying on a large biological system for a pregnant woman with red blood. Stem cells They also release DNA fragments into the bloodstream. Approximately 10 percent of circulating cfDNA is placental; The remaining 90 percent comes from the mother.
Previous studies have shown that there may be patients with cancer Abnormal cfDNA signatures. in addition, Several case reports they have Abnormal prenatal cfDNA is described Check that It led to a cancer diagnosis. Turriff and her colleagues wanted to see if the CFNA test, which is routinely given to pregnant women in the US, could be used to detect cancer.
Their study, involving 107 pregnant women between December 2019 and December 2023, returned abnormal results from prenatal cfDNA testing that could not be clearly interpreted as fetal abnormalities.
The researchers conducted MRI scans of the patients as well as other routine diagnostic tests and determined that 52 of them had previously undiagnosed cancers in their bodies: 32 were blood cancers (31 were lymphomas) and 20 were tumors. One patient had a tumor the size of a grapefruit; Two others had rare bile duct cancer.
By a large margin, MRI was the best diagnostic tool. Routine tests such as physical examination and patient history have limited utility, the researchers found.
What makes the findings particularly concerning is the patient's presentation. Of the 52 patients diagnosed with cancer, 29 were asymptomatic. An additional 13 patients developed symptoms of cancer due to their pregnancy. And 10 of the 52 patients either didn't recognize their own symptoms or were examined and received confirmatory test results.
Of the 55 patients in the study who did not have cancer, the most common diagnosis was uterine fibroids -- but benign. It still causes complications During pregnancy, and therefore should be under the supervision of the patient's doctor. These, in turn, can be taken with an MRI.
A study on prenatal CFNA screening and cancer in the Netherlands in 2022 It had the same results.
These cases are very rare, so there is no reason to panic. Instead, the researchers say the results highlight the need to include a cancer diagnosis in routine abnormal CFNA results — especially in the large number of patients who are either asymptomatic or have symptoms ruled out.
MRI screening for cancer, doctors say, should be included in the treatment toolkit when presented with difficult-to-interpret abnormal cfDNA results.
The study was published in New England Journal of Medicine.
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