Incidental Detection of Maternal Malignancy by Fetal Cell-Free DNA Screening.

Cell-free DNA is an advancing technology with increasing applications in screening, diagnosis, and treatment for several disease processes. The shared physiologic, genetic, and epigenetic characteristics of placental physiology and tumor development have become apparent to both clinicians and researchers. Maternal malignancy has been reported as a cause of false-positive prenatal cell-free DNA screening results. The detection of multiple aneuploidies or a single autosomal monosomy increases the chance for an underlying maternal malignancy when the result is discordant with fetal diagnostic testing. There is currently no consensus guideline on counseling and evaluation of patients with concern for malignancy from cell-free DNA testing. Furthermore, laboratories differ significantly in reporting policies, terminology, and in reporting strategies and methods used for unexpected or incidental findings. The ordering practitioner is therefore tasked to understand the policies of their laboratory of choice to provide adequate pretest and posttest genetic counseling. In pretest counseling, the potential for incidental or unexpected findings or nonreportable results should be explained. With an abnormal, unanticipated, or nonreportable result, posttest counseling should include a description of possible fetal or maternal diagnoses, including malignancy. Health care professionals should explain options for further evaluation and management, including a recommendation for fetal diagnostic testing. The medical workup recommended by various authors to evaluate cancer risk is based on consensus, experience, and expert opinion. These strategies should incorporate the patient's desire for information, cost, and family and personal medical history. Ongoing research and multi-disciplinary collaboration in this area is critical to identify best practices in management of complex results from this increasingly common screening test.