Noninvasive Prenatal Test Results Indicative of Maternal Malignancies: A Nationwide Genetic and Clinical Follow-Up Study.

PURPOSE: Noninvasive prenatal testing (NIPT) for fetal aneuploidy screening using cell-free DNA derived from maternal plasma can incidentally raise suspicion for cancer. Diagnostic routing after malignancy suspicious-NIPT faces many challenges. Here, we detail malignancy suspicious-NIPT cases, and describe the clinical characteristics, chromosomal aberrations, and diagnostic routing of the patients with a confirmed malignancy. Clinical lessons can be learned from our experience. METHODS: Patients with NIPT results indicative of a malignancy referred for tumor screening between April 2017 and April 2020 were retrospectively included from a Dutch nationwide NIPT implementation study, TRIDENT-2. NIPT profiles from patients with confirmed malignancies were reviewed, and the pattern of chromosomal aberrations related to tumor type was analyzed. We evaluated the diagnostic contribution of clinical and genetic examinations. RESULTS: Malignancy suspicious-NIPT results were reported in 0.03% after genome-wide NIPT, and malignancies confirmed in 16 patients (16/48, 33.3%). Multiple chromosomal aberrations were seen in 23 of 48 patients with genome-wide NIPT, and a malignancy was confirmed in 16 patients (16/23, 69.6%). After targeted NIPT, 0.005% malignancy suspicious-NIPT results were reported, in 2/3 patients a malignancy was confirmed. Different tumor types and stages were diagnosed, predominantly hematologic malignancies (12/18). NIPT data showed recurrent gains and losses in primary mediastinal B-cell lymphomas and classic Hodgkin lymphomas. Magnetic resonance imaging and computed tomography were most informative in diagnosing the malignancy. CONCLUSION: In 231,896 pregnant women, a low percentage (0.02%) of NIPT results were assessed as indicative of a maternal malignancy. However, when multiple chromosomal aberrations were found, the risk of a confirmed malignancy was considerably high. Referral for extensive oncologic examination is recommended, and may be guided by tumor-specific hallmarks in the NIPT profile.

TRIDENT-2: National Implementation of Genome-wide Non-invasive Prenatal Testing as a First-Tier Screening Test in the Netherlands.

The Netherlands launched a nationwide implementation study on non-invasive prenatal testing (NIPT) as a first-tier test offered to all pregnant women. This started on April 1, 2017 as the TRIDENT-2 study, licensed by the Dutch Ministry of Health. In the first year, NIPT was performed in 73,239 pregnancies (42% of all pregnancies), 7,239 (4%) chose first-trimester combined testing, and 54% did not participate. The number of trisomies 21 (239, 0.33%), 18 (49, 0.07%), and 13 (55, 0.08%) found in this study is comparable to earlier studies, but the Positive Predictive Values (PPV)-96% for trisomy 21, 98% for trisomy 18, and 53% for trisomy 13-were higher than expected. Findings other than trisomy 21, 18, or 13 were reported on request of the pregnant women; 78% of women chose to have these reported. The number of additional findings was 207 (0.36%); these included other trisomies (101, 0.18%, PPV 6%, many of the remaining 94% of cases are likely confined placental mosaics and possibly clinically significant), structural chromosomal aberrations (95, 0.16%, PPV 32%,) and complex abnormal profiles indicative of maternal malignancies (11, 0.02%, PPV 64%). The implementation of genome-wide NIPT is under debate because the benefits of detecting other fetal chromosomal aberrations must be balanced against the risks of discordant positives, parental anxiety, and a potential increase in (invasive) diagnostic procedures. Our first-year data, including clinical data and laboratory follow-up data, will fuel this debate. Furthermore, we describe how NIPT can successfully be embedded into a national screening program with a single chain for prenatal care including counseling, testing, and follow-up.

Trial by Dutch laboratories for evaluation of non-invasive prenatal testing. Part I-clinical impact.

OBJECTIVE: To evaluate the clinical impact of nationwide implementation of genome-wide non-invasive prenatal testing (NIPT) in pregnancies at increased risk for fetal trisomies 21, 18 and 13 (TRIDENT study). METHOD: Women with elevated risk based on first trimester combined testing (FCT ≥ 1:200) or medical history, not advanced maternal age alone, were offered NIPT as contingent screening test, performed by Dutch University Medical laboratories. We analyzed uptake, test performance, redraw/failure rate, turn-around time and pregnancy outcome. RESULTS: Between 1 April and 1 September 2014, 1413/23 232 (6%) women received a high-risk FCT result. Of these, 1211 (85.7%) chose NIPT. One hundred seventy-nine women had NIPT based on medical history. In total, 1386/1390 (99.7%) women received a result, 6 (0.4%) after redraw. Mean turn-around time was 14 days. Follow-up was available in 1376 (99.0%) pregnancies. NIPT correctly predicted 37/38 (97.4%) trisomies 21, 18 or 13 (29/30, 4/4 and 4/4 respectively); 5/1376 (0.4%) cases proved to be false positives: trisomies 21 (n = 2), 18 (n = 1) and 13 (n = 2). Estimated reduction in invasive testing was 62%. CONCLUSION: Introduction of NIPT in the Dutch National healthcare-funded Prenatal Screening Program resulted in high uptake and a vast reduction of invasive testing. Our study supports offering NIPT to pregnant women at increased risk for fetal trisomy. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

Factors determining uptake of invasive testing following first-trimester combined testing.

OBJECTIVE: This study aims to analyze differences in characteristics between women who opted for invasive testing after first-trimester combined testing and those who did not. METHOD: Follow-up was performed in 20 215 combined tests conducted between 2007 and 2011 in the central region of the Netherlands. Multivariate logistic regression analysis compared variables (Down syndrome risk estimate, maternal age, previous Down syndrome pregnancy, IVF/ICSI, parity and nuchal translucency measurement) between different groups. RESULTS: 65.4% of women with a Down syndrome risk estimate ≥1 in 200 opted for invasive 49 testing. In a multivariate model, women opting for invasive testing were significantly younger (odds ratio 0.92; 95% confidence interval 0.88-0.95) and less likely to have had IVF/ICSI (odds ratio 0.57; 95% confidence interval 0.37-0.87) than women opting out on invasive testing. In this high risk group, women <36 years opted for invasive testing more frequently, regardless of their Down syndrome risk estimate magnitude. Women ≥36 years let the magnitude of the risk estimate count significantly in their decision to opt for invasive testing. CONCLUSION: Because of the dissimilarity in the offer of prenatal screening and invasive diagnosis in the Dutch prenatal screening policy, women <36 years and women >36 years make different choices when confronted with similar Down syndrome risk estimates.

Trends in the utilization of invasive prenatal diagnosis in The Netherlands during 2000-2009.

OBJECTIVE: To analyze trends in the number and type of invasive procedure, reasons for referral, maternal age and chromosomal abnormalities over a 10-year period and correlate the trends to changes in the national prenatal screening policy. METHODS: Data from 10 706 invasive prenatal procedures yielding a full karyotype, performed between 2000 and 2009 were extracted from the cytogenetic database in the central region of The Netherlands. Trends were analyzed. RESULTS: Over a 10-year period, the number of invasive procedures halved and the percentage of chromosomal abnormalities detected, increased from 5.5 to 9.4%. After 2007, however, 5.7% of karyotypes in women over 36 years were found to be abnormal, versus 18.1% in women below 36 years. In 2009, 71.5% of women over 36 are still referred for invasive prenatal diagnosis on the indication advanced maternal age. CONCLUSIONS: Changes in prenatal screening policy significantly increased referral after screening and improved the efficacy of invasive prenatal diagnosis. We show the continuing effect of the different policies applied in the past to women below and above the age of 36. To further improve efficacy of invasive prenatal diagnosis, first trimester combination screening should be actively offered to women of all ages.

Aiming at multidisciplinary consensus: what should be detected in prenatal diagnosis?

OBJECTIVE: To determine expert consensus on which chromosomal abnormalities should and should not be detected in prenatal diagnosis, and for which abnormalities disagreement remains after structured discussion. METHODS: An expert panel of 24 prenatal experts (8 clinical cytogeneticists, 8 clinical geneticists and 8 obstetricians) rated 15 chromosomal abnormalities sampled from a nationwide study on rapid aneuploidy detection (RAD). In two individual anonymous rating rounds and one group meeting, the participants rated PRO or AGAINST detection and stated their main argument. The 15 chromosomal abnormalities were described in detail by a stylized vignette containing an obstetrical history, the indication for prenatal diagnosis and the range of possible outcomes of the chromosomal abnormality. Consensus was defined to be present if at least 80% of the experts agreed. RESULTS: Consensus was reached in 12 out of 15 cases. In ten cases, there was agreement PRO detection and in two cases experts agreed AGAINST detection. At the end of the third round, dissensus remained on three abnormalities. CONCLUSION: Experts largely agreed on detecting chromosomal abnormalities with severe consequences and AGAINST detection in case of irrelevant clinical consequences. For chromosomal abnormalities with mild or uncertain outcomes, dissensus remained. None of the currently available tests corresponds to these demands.

The fate of the mosaic embryo: chromosomal constitution and development of Day 4, 5 and 8 human embryos.

BACKGROUND: Post-zygotic chromosome segregation errors are very common in human embryos after in vitro fertilization, resulting in mosaic embryos. However, the significance of mosaicism for the developmental potential of early embryos is unknown. We assessed chromosomal constitution and development of embryos from compaction to the peri-implantation stage. METHODS: From 112 cryopreserved Day 4 human embryos donated for research, 21 were immediately fixed and all cells were analysed by fluorescent in situ hybridization (FISH) for chromosomes 1, 7, 13, 15, 16, 18, 21, 22, X and Y. The remaining 91 embryos were thawed, with 54 embryos undergoing biopsy of one or two cells which were fixed and analysed by FISH. Biopsied embryos were kept in standard culture conditions for 24 h. Embryos arrested before cavitation (n = 24) were fixed whereas developing Day 5 blastocysts (n = 24) were co-cultured for a further 72 h on an endometrial monolayer followed by fixation. Cell numbers were counted and all nuclei were analysed by FISH. Data from a previous FISH analysis on cryopreserved good-quality Day 5 blastocysts (n = 36) were also included in the present study. RESULTS: FISH analysis was successful for 18 Day 4 fixed embryos and, according to our definition, 83% were mosaic and 11% showed a chaotic chromosomal constitution. FISH analysis of two blastomeres from Day 4 developing embryos showed that 54% were mosaic, 40% were normal and 6% were abnormal. Analysis of Day 4, 5 and 8 whole embryos showed a decrease in incidence of mosaicism over time, from 83% on Day 4 to 42% on Day 8. A significant positive correlation was observed between the total cell number and the percentage of normal cells in developing Day 5 and Day 8 embryos but not in developing Day 4 or embryos arrested before cavitation. CONCLUSIONS: These data suggest that both the developmental arrest of a significant proportion of mosaic embryos on Day 4, and the cell death or reduced proliferation of aneuploid cells within an embryo may be responsible for the observed decrease of aneuploid blastomeres from compaction to the peri-implantation stage.

Trisomy 13 or 18 (mosaicism) in first trimester cytotrophoblast cells: false-positive results in 11 out of 51 cases.

OBJECTIVE: The finding of full or mosaic trisomy 13 or 18 in first trimester chorionic villus sampling (CVS) may be a false-positive result. This report provides incidence and outcome information that may be helpful in counselling individual patients and in choosing adequate follow-up. STUDY DESIGN: From a series of 6820 CVS cases, we retrospectively collected data on all patients (n=51) with full (n=30) or mosaic (n=5) trisomy 18, and full (n=13) or mosaic (n=3) trisomy 13 in cytotrophoblast cells. RESULTS: Five false-positives were seen in patients with full trisomy 18 and three in the mosaic cases. One false-positive result was observed in full trisomy 13 and two false-positives in cases of mosaicism. No false-negative results were reported. CONCLUSION: The diagnosis of trisomy 13 or 18 in cytotrophoblasts should be confirmed in other tissues, unless fetal abnormalities are seen at ultrasound. In case of mosaicism, follow-up amniocentesis is advised.