Cell-free DNA screening results by stage of maternal malignancy.

BACKGROUND

Cell-free DNA (cfDNA) screening is increasingly used for fetal aneuploidy screening. Maternal malignancy is associated with abnormal cfDNA results; however, the impact of tumor staging and origin on cfDNA results remains unclear.

OBJECTIVE

To characterize the types and stages of malignancies resulting in abnormal cfDNA screening results.

STUDY

DESIGN

This is a single-center, retrospective review of cases with a known, suspected, or incidentally diagnosed malignancy during pregnancy from 2015 to 2023, queried using ICD9/10 codes for malignancy. We extracted maternal medical history, cancer history, aneuploidy screening results, and fetal outcomes. We used Fisher's exact and Wilcoxon rank sum tests to determine associations between cfDNA screening results and (1) demographic factors, (2) cancer characteristics, and (3) fetal outcomes.

RESULTS

We identified 97 cases of malignancy in pregnancy. Thirty-three patients had no aneuploidy screening. Twenty-two underwent first-trimester screening, and 4 underwent quad screening, all with low-risk results. Among the 38 patients who had cfDNA screening, 21.1% (8/38) were hematologic, and 78.9% (30/38) were solid tumors. The most common locations were breast (11/38), blood (8/38), and gastrointestinal (5/38). Overall, 31.6% (12/38) of patients had abnormal cfDNA results. The fraction of stage 0, I, II, III, and IV solid cancers with abnormal cfDNA results was 0/4 (0%), 0/5 (0%), 2/6 (33.3%), 1/4 (25%), and 7/11 (63.6%), respectively. Metastasized status was significantly different between groups: 47.6% (10/21) of patients with stage II to IV solid cancers had abnormal cfDNA results, compared to 0% (0/9) of patients with stage 0 to I solid cancers (P=.013). No fetuses had a confirmed aneuploidy.

CONCLUSION

Our data suggest that early-stage, solid tumors are less likely to impact cfDNA screening results than metastatic tumors. Larger cohorts are needed to further characterize the association between tumor type/stage and cfDNA result. Ultimately, cfDNA screening may be more likely to incidentally diagnose certain types of maternal malignancy than others.