IF FIFTY IS THE NEW FORTY…THEN 1 ST TRIMESTER SCREENING IS THE NEW THIRTY FIVE James Keller MD

BACKGROUND

Down Syndrome Risk Assessment Maternal age was the original “screening test” used in determining which women would undergo invasive testing for fetal Down syndrome. Since most children with Down syndrome are born to women younger than 35, most affected pregnancies will not be detected using age as a screening test. In the early 1980s it was discovered that MSAFP was significantly lower in mothers carrying a fetus affected with trisomy 21 (0.74 MoM). Other analytes added to refine screening to increase detection rate and to decrease false positives

QUAD SCREEN Intact HCG is 2.06 MoM in DS compared to euploid Unconjugated estriol is is 0.75MoM compared to euploid Inhibin A 1.77 MoM in DS compared to euploid The detection rate of the quad screen was 80% with a 5% false positive rate This is a good test..remember why we wanted better

Timing of Aneuploidy Risk Assessment Data from patient questionnaires demonstrated a clear preference for earlier risk assessment, even at the risk of slightly higher FPR and/or slightly lower detection rates Spencer et al. Ultrasound Obstet Gynecol 2004;24:735. Sharma et al. Am J Obstet Gynecol 2005; 193: 1429.

Nuchal Translucency “…The skin…is deficient in elasticity, giving the appearance of being too large for the body.” Down L. Observations on an ethnic classification of idiots. Clin Lectures and Reports 1866;3:

Nuchal Translucency

Gestation 11w1d-13w6d Gestation 11w1d-13w6d CRL mm CRL mm Mid-sagittal view Mid-sagittal view Image size: callipers 0.1mm Image size: callipers 0.1mm Neutral position Neutral position Away from amnion Away from amnion Maximum lucency Maximum lucency Callipers on-to-on Callipers on-to-on

Down Syndrome Risk Assessment The Fetal Medicine Foundation screened approximately 100,000 pregnancies in 22 centers in the United Kingdom. Standardized techniques were used. At a risk cutoff of 1 in 300, the sensitivity was 82.2% for Down syndrome and 77.9% for other chromosomal abnormalities, with a false-positive rate of 8.3%. Snijders et al. Lancet 1998;351:343.

Free ß-hCGPAPP-A The search was on for analytes which could be added to the NT to refine the test

First Trimester Screening for Trisomies 21 and 18 Wapner et al, NEJM 2003 Known as the BUN study Used screening positive parameters still in use 1/270, for trisomy 21, 1/150 for trisomy participating institutions 8816 patients

BUN STUDY PATIENTDETECTION RATE (%) (1/270) FALSE POSITIVE (%) MATERNAL AGE8048 AGE + BIOCHEM8523 AGE + NT8212 AGE + NT + BIOCHEM 859 AGE<35674 AGE>/= Proved effective screening possible in the 1 st trimester

It was to be expected that a trial be performed to look at all screening tests to date

First-Trimester or Second-Trimester Screening, or Both, for Down's Syndrome Fergal D. Malone, M.D., Jacob A. Canick, Ph.D., Robert H. Ball, M.D., David A. Nyberg, M.D., Christine H. Comstock, M.D., Radek Bukowski, M.D., Richard L. Berkowitz, M.D., Susan J. Gross, M.D., Lorraine Dugoff, M.D., Sabrina D. Craigo, M.D., Ilan E. Timor-Tritsch, M.D., Stephen R. Carr, M.D., Honor M. Wolfe, M.D., Kimberly Dukes, Ph.D., Diana W. Bianchi, M.D., Alicja R. Rudnicka, Ph.D., Allan K. Hackshaw, M.Sc., Geralyn Lambert-Messerlian, Ph.D., Nicholas J. Wald, F.R.C.P. and Mary E. D'Alton, M.D. N Engl J Med Volume 353;19: November 10, 2005

WHAT WAS TESTED 1 ST trimester serum screening combined 1 st trimester combined screening (serum+NT) 2 nd trimester quad screen Independent sequential screening-pt provided results of 1 st and 2 nd trimester testing Stepwise sequential screening, like independent, but overall 2 nd trimester risk calculated, using all data Serum integrated screening-PAPPA+quad screen Fully integrated uses NT in addition to serum integrated screening All tests take into account maternal age

RELEVANT TESTS 1 ST TRIMESTER COMBINED SCREENING “NT” QUAD SCREEN INTEGRATED TEST – Fully integrated – Serum integrated SEQUENTIAL – Independent – Stepwise – Contingent

DETECTION RATE (%) 5% FALSE POSITIVE WEEKS ND TRI TEST NT serum Combined (nt+serum) Serum integrated Fully integrated Triple69 Quad81

DETECTION RATE (%) 5% FALSE POSITIVE at 12 WEEKS (FASTER TRIAL) TESTDETECTION RATE (%) TRIMESTER OF DX NT COMBINED851ST INTEGRATED95 2ND STEPWISE SEQUENTIAL951 ST OR 2ND CONTINGENT SEQUENTIAL921 ST OR 2ND

EXPERT OPINION ACOG A strategy that incorporates both first and second trimester screening should be offered to woman who seek prenatal care in the first trimester Woman found to have an increased risk of aneuploidy with first-trimester screening should be offered genetic counseling and diagnostic testing These are conflicting statements leading to confusion about aneuploidy screening

WOMAN WANT EARLY SCREENING

PATIENT PREFERENCES FOR SCREENING IN THE FIRST TRIMESTER Werner at al Prenatal Diagnosis 2008 Formal genetic counseling offering integrated screening or first trimester screening 60% chose 1 st trimester screening vs. 40% choosing integrated As expected the motivation for the choice was early results versus most information

HOW RELEVANT ARE THE DATA TO THE REAL WORLD? Almost all studies are based upon modeling rather than a true clinical trial There are relatively few clinical trials where these models have been tested A case cannot be detected with a screening test alone Reluctance to undergo a diagnostic test will lead to an undiagnosed case, even in a screen positive patient

SEQUENTIAL SCREENING IN PRACTICE STEPWISE SEQUENTIAL SCREENING FOR FETAL ANEUPLOIDY Benn, et al AJOG 2007

Sequential Screening 1528 woman, average age 36.2 years 133 woman, positive 1 st trimester – 30 chose cvs – 88 sequenced – 15 stopped 88 sequenced – 30 positive 25 declined amniocentesis in spite of two positive tests 5 had amniocentesis – 58 negative Of 35 woman who chose invasive testing, 30 chose after 1 st trimester testing

Sequential Screening 1395 screened negative 1 st trimester – 0 had invasive testing 1085 sequenced (300 stopped testing) 30 positive, – 13 amnios, 17 no testing ThreeTrisomy 21’s in the 1528patients, two detected in 1 st trimester and one after positive 1 st and 2 nd trimester tests

Sequential Screening 1283 patients having 1 st trimester elsewhere then included, due to small numbers 2456 women, 6 cases of trisomy 21, 5 of six detected in the 1 st trimester One of six, would have been missed by 1 st trimester screening One of six, would have been missed by sequential or certainly integrated screening (1:91, 1:574) In this study both tests performed equally, with NT combined yielding an earlier diagnosis

Sequential Screening Other Lessons The majority of people who screened positive, do not have a diagnostic test-especially those who screen positive twice (25/30), 17 of 30 who screen positive only by their integrated result, also do not test. Of the 48 patients who had an indicated diagnostic test with sequential screening-30 chose after the 1 st trimester test

CONTINGENT SEQUENTIAL Patients undergo 1 st trimester screening If very high risk (>1:30-1:50) are offered diagnostic testing If very low risk (<1:1500-1:2000) are finished with testing If intermediate, go on to integrated testing scheme

Contingent Sequential Withholding of abnormal test results – Model only works if 1 st trimester diagnostic test only offered to risks much greater than standard accepted (1/30) 20-25% of people, will be flagged for further testing – Some with classically low risks (1/ ), may consider an invasive test when they cannot be reassured by 1 st trimester results – This will eliminate any advantage in false positive rate

STEPWISE SEQUENTIAL Over 90% of patients will need to proceed to 2 nd trimester testing Patients with high risk results may be falsely reassured by second test Clinical experience shows that those with a positive 1 st trimester screen who choose further testing unlikely to have a diagnostic test, thus increasing expense with little contribution to detection rate

Pitfalls of Integrated Testing Theoretically this is the best test – Highest detection rate – Lowest false positives Is it ethical to withhold a positive screening results in the hopes it will be corrected – And what if it is incorrectly corrected – In true integrated testing you wont know What if the test isn’t completed

INTEGRATED TEST No shows for second test – Whose liability? Withholding abnormal results which could result in significant clinical advantage Extra cost May be an advantage to this test when NT cannot be performed

COMBINED NT USING FREE BETA hCG

CLINICAL USE OF 1 ST TRIMESTER ANEUPLOIDY SCREENING IN A U.S. POPULATION CAN REPLICATE DATA FROM CLINICAL TRIALS PERNI et al AJOG 2006

4883 patients, Cornell University, median maternal age 33 years old 22 cases of trisomy 21 Detection rate 91%, false positive rate 5% for trisomy 21 All cases of trisomy 18 detected Used Free Beta-hCG, NTD labs

Is it a Myth or a Fact By Larry Platt, OB/GYN NTOC Member Prof. Ob-Gyn, Geffen School of Medicine at UCLA, Director, Center for Fetal Medicine and Women's Ultrasound MYTH: ACOG Practice bulletin mandates integrated testing as the method of choice for prenatal diagnosis. FACT: The ACOG PB provides a variety of ways to achieve the most desirable outcome including combined First Trimester risk assessment with NT and biochemistry alone, second trimester alone or a combination of testing schemes etc. Quality monitoring of NT performance is emphasized as essential.

NASAL BONE

© 2007 Nuchal Translucency Quality Review. Reproduction permitt ed for personal educational use only. Other usage requires consent of Maternal-Fetal Medicine Foundation. Content may not be modified in any way without permission. Tip of Nose Skin at Nasal Bridge Nasal Bone

© 2007 Nuchal Translucency Quality Review. Reproduction permitt ed for personal educational use only. Other usage requires consent of Maternal-Fetal Medicine Foundation. Content may not be modified in any way without permission. Tip of Nose 4th AS 3rd

Cicero S, Avgidou K, Rembouskos G, Kagan KO, Nicolaides KH. Nasal bone in first-trimester screening for trisomy 21. Am J Obstet Gynecol 2006 Study of a high-risk population with a median maternal age of 35 years assessed by nuchal translucency, nasal bone, and biochemistry Estimated that 93.6% of Down syndrome cases would be detected at a false-positive rate of 5%. For a false-positive rate of 2.5%, the detection rate would be 90.0% The experience of highly specialized and high-risk centers and are not generalizable to less experienced centers.

INSTANT SCREENING

LMP Pregnancy Test Pregnancy Test free-Beta / PAPP- A Diagnosis Conception Weeks Instant Risk Assessment CVS NT

SUMMARY Most models show an advantage in integrated or sequential screening programs as compared to combined NT screening alone This has not been shown in large clinical trials where decisions about accepting invasive testing has been included. When those decisions are included, the largest trial available showed a 90% detection rate using combined NT alone Combined NT using free beta hCG is an appropriate screen for Down Syndrome