1. Is there over-enthusiasm for Non-Invasive Testing?
Frank A. Chervenak, MD
Shari E. Gelber, MD, PhD
Tracy B. Grossman, MD MSc
Laurence B. McCullough, Ph.D.
Fix text
University of Hawaii
December
Honolulu, Hawaii

3. Logarithmic axis
Moore’s law (gordon Moore) co founder of intel. Doubling every year of the number of transistors in an integrated circuit. Allowed for development of digital electronics. Became a self fullfilling prophecy
Genetics is now on a more rapid move forward

4. How do Tests Get Conveyed to the Public?
First testing that has been industry driven….

9. What is cfDNA?
Pieces of DNA from the fetal tissue end up in maternal serum
Most labs need a certain percentage of fetal DNA found in the serum to report a result
Lab is able to separate maternal DNA from fetal DNA using various techniques
Usually by 9-10 weeks there will be enough circulated fetal DNA in maternal serum to report a result

10. RISK DIAGNOSIS SCREENING TESTING
The term NIPT conflates screening and testing
SCREENING TESTING

11. Aneuploidy Screening vs Testing
Invasive Testing
Risk of carrying fetus with a common aneuploidy (TS 13, 18, 21)
Presence or absence of abnormalities in chromosome number
Deletions and Duplications
Evaluation of specific genetic disorders

12. Characteristics of a Screening Test
Condition should be an important health problem
There should be a test for the condition
Facilities for diagnosis and treatment should be available
The test should be acceptable to the population
The natural history of the disease should be adequately understood
The total cost of finding a case should be economically balanced in relation to medical expenditure as a whole
Put in reference?
Do you want reminders or do you want to read this?

13. Characteristics of a Screening Test
Case-finding should be a continuous process
Test used should be sensitive
There should be a treatment for the condition
There should be a latent or asymptomatic stage of the disease
There should be an agreed policy on who to treat
Remember to say: There is an intervention and people do benefit from counseling.
This isn’t just about termination of pregnancy. Patients who know the fetus have TS21 may get a fetal echo, additional monitoring. Patients with TS 18 may chose not to have a cesarean for fetal indications….

14. Important to remember other benefits to screening than termination of pregnancy
Insert respect for autonomy slide.

15. More information – can help patient decide on next steps, such as:
Patient autonomy
More information – can help patient decide on next steps, such as:
Additional testing (amniocentesis, CVS)
Counseling by specialists (pediatric cardiologists, neonatologists, pediatric surgeons)
Patient has option of continuation of pregnancy or termination

16. Examples of Screening Tests for Aneuploidy
AGE
AFP
Ultrasound
Triple
Quad
Penta
1st Trimester risk assessment (NT+biomarkers)
Integrated
Sequential
Contingent
NIPT/S= cfDNA

17. NIPT/S= cfDNA is just another screening test
Public perception is different because of marketing, overselling, and improved sensitivity for TS21.
Potential to be used by patients without physician counseling / involvement.

18. Sensitivity of Aneuploidy Screens for TS21
Screening test
Detection Rate
Triple screen
69%
Quad screen
81%
NT alone
64-70%
First trimester
(NT+ biomarkers)
82-87%
Integrated
96%
Sequential Stepwise
95%
Contingent
88-94%
cfDNA
99% (in patients who receive result)
Who doesn’t receive result:
Overweight but also those with chromosome anomalies (DO YOU WANT THIS ON A SLIDE)
Review table with FAC. Ultrasound.
Ultrasound

19. Non Genetic Benefits of Screening Tests
Quad screen
Analytes associated with preeclampsia, growth restriction
Screen for oNTD
First trimester
(NT+ biomarkers)
1. Independently associated with structural malformations
2. Analytes associated with preeclampsia, growth restriction.
3. Individual assessment of multifetal gestation
cfDNA
1. Identification of fetal gender.
2. Identification of fetal rH status.
TABLE
cfDNA really genetic

20. Limitations of Screening Tests
Benefit
Quad screen
Lower detection rate than combined tests.
2. Information provided late.
3. Requires accurate dating.
First trimester
(NT+ biomarkers)
1. Requires technical expertise
cfDNA
1. PPV/NPV not clearly reported.
2. Higher false positive rate in lower risk patients.
3. Studies did not duplicate real world experience. (newest test)
4. No other clues for other conditions
TABLE
cfDNA really genetic

21. Large study comparing standard screening to cfDNA
BUT 488 did not have cfDNA result and these were excluded.
STUDY NOT ITT
These patients were increased risk for aneuploidy!
False positive rate lower with cfDNA
9 FP to pick up 38 TP
False positive rate higher with SS.
854 FP to pick up 30 TP

22. cfDNA is the better test for TS21screening Standard screening is an excellent test
= good
= fair
= poor
= fail

23. Why do we care so much about TS21?
Integrated
Quad NT
Contingent
Sequential
AGE
TS21 is the most common disorder. BUT, the sum of all the disorders that are NOT TS21 is far greater than the risk of TS21
Why do we care so much about TS21?
Why are we so focused on TS 21

24. cfDNA is the better test for TS21 screening but not for everything.
(77.1)

25. Author’s comment: “For primary population screening, cfDNA provides lower DR than sequential screening if considering detection of all chromosomal abnormalities. cfDNA should not be adopted as primary screening without further evaluation of the implications for detection of all chromosomal abnormalities and how to best evaluate no results cases.”

26. Abnormal screening with normal karyotype is still a “high risk” condition
Patients with invasive testing still had residual risk of >1% for pathogenic mutation or mutation with potential for clinical significance in setting of normal karyotype
Risk with ultrasound anomaly = 6%

27. Why Not Just do Multiple Screening Tests?
Increased false positive rate
Incremental increase in detection rate
How to deal with conflicting results?
Cost

28. Abnormal Nuchal translucency result and normal cfDNA results
Challenging to counsel these patients!
Normal cfDNA and abnormal Nuchal Translucency (NT)
Abnormal NT and patient doesn’t want amniocentesis or CVS – might choose to have cfDNA instead
There are risks of amnio and CVS – pregnancy loss!
Some patients may want to avoid these risks and would rather have cfDNA instead.

29. What does ACOG say?
All pregnant women have option of screening or diagnostic testing
Diagnostic testing is recommended with every abnormal nuchal translucency
Diagnostic testing with amnio and CVS – recommended after every abnormal NT

30. Abnormal NT
Increased nuchal translucency is associated with other abnormalities other than Trisomy 13, 18, 21 –
Noonan syndrome
Cardiac abnormalities

31. Examples of Abnormal NT: genetic results
Abnormal NT is a condition, and not a diagnosis
All of these fetuses had NTs of around 3.5mm. Among these four patients, one had normal genetic testing, one had Trisomy 21, one had a pathogenic copy number variant, and one had Noonan syndrome.
Could you tell the difference if I didn’t give you the labels with each image?
You wouldn’t know unless you did invasive testing!

32. What does SMFM say?
Patients who decline invasive diagnostic testing may choose to have NIPS/T as an alternative
There is still a role for ultrasound in first trimester – assess both nuchal translucency and for a basic anatomic survey – picks up anomalies earlier

33. Residual risk of genetic abnormality after normal cfDNA
Retrospective study- patients with NT ≥ 3.0mm that also had genetic testing
Compared the proportion of genetic abnormalities detectable with cfDNA vs other genetic abnormalities were made based on:
NT size: (<3.5mm vs ≥ 3.5mm)
Maternal age (< age 35, ≥ age 35)
This study was done by one of my fellows at my institution.
Over two years, pregnancies with nuchal translucency ≥ 3.0mm identified on ultrasounds performed at our institution were identified.
Pregnancies with an abnormal nuchal translucency and genetic testing results were included, whether or not noninvasive prenatal testing was performed.
Genetic testing included: karyotype, microarray, Noonan syndrome, and testing for other single gene disorders. This testing was done prenatally via CVS or amniocentesis, postnatally, or on products of conception after a termination of pregnancy.
Abnormalities considered “detectable” by NIPT included: Trisomy 13, 18, 21, sex chromosome aneuploidy and triploidy.
Results were stratified based on 2 criteria:
Absolute NT value and maternal age
Patients with NIPT and without NIPT performed were included in the study.

34. Results: What would cfDNA miss?
110 patients included
60 had genetic abnormalities
73.3% were “detectable” by cfDNA
26.7% were “not detectable”
All abnormalities with NT < 3.4mm were detectable by cfDNA
If NT ≥ 3.5mm, 71.4% of abnormalities were detectable by cfDNA
For NT 3.5mm or greater, a significant proportion of abnormalities would NOT be detected (about 30%!)

35. Results: What would cfDNA miss?
For patients with NT ≥3.5mm:
≥ age 35:
87.1% of abnormalities would be detected by cfDNA
< age 35
only 52.0% (13 of 25) abnormalities would be detected by cfDNA
Most abnormalities detected in patients over age 35, if NT was 3.5mm or greater
BUT, for younger women, about half would be detected by cfDNA if NT was 3.5mm or greater – that’s not that many!

36. Conclusions of the study
Normal cfDNA may be reassuring in those with mildly abnormal nuchal translucency
But, a significant proportion of abnormalities in those with nuchal translucency ≥ 3.5mm would not be detected.
This is particularly true in younger women, in whom cfDNA would miss about half of genetic abnormalities.

37. SMFM goes along with this as well – use NIPT for high risk women – (over age 35) – more useful for counseling

38. Role of ultrasound in women with cfDNA screening
January 2017 – SMFM Consult series – addressed the question of role of ultrasound in women undergoing NIPS/T

39. SMFM Consult Series #42 SMFM states:
In women who are considering cfDNA, first trimester NT assessment is beneficial – help choose between screening and diagnostic testing
If abnormal nuchal translucency, or structural abnormalities – may choose diagnostic testing instead of screening
But, if women already have a cfDNA result that is negative – first trimester nuchal translucency screening may slightly decrease residual risk of abnormalities.
SMFM says: future research is needed to determine optimal screening approach in these patients
In women with negative cfDNA: “first trimester NT screening may be little additional benefit as a screening test – due to how good cfDNA is at picking up the most common genetic abnormalities.”

40. Ultrasound in the era of cfDNA
Study by Reiff, et al:
1739 patients with ultrasounds at weeks, and with a negative cfDNA
Abnormal ultrasound findings identified in 1 in 28 women
Fetal anomaly identified in 1 in 290
Unexpected findings: seen on sono:
Twins
Fetal demise
Structural abnormalities

41. Conclusions
cfDNA has been aggressively marketed to physicians and patients as a test not a screen
cfDNA is an incremental advance not a change
cfDNA is the best screening test for TS21
This information comes at the expense of other information that may be more important to patients

42. Is there over-enthusiasm for Non-Invasive Testing?
Frank A. Chervenak, MD
Shari E. Gelber, MD, PhD
Tracy B. Grossman, MD MSc
Laurence B. McCullough, Ph.D.
Fix text
University of Hawaii
December
Honolulu, Hawaii