Abstract P3-07-18: Utilization and impact of oncotype DX 21- gene breast cancer assay in clinical practice across the US: 2010-2012 National cancer data base analysis
Authors: Orucevic A , Heidel RE , Bell JL 
Published: May 2016

Oncotype DX (OD), initially used for early stage estrogen receptor-positive (ER+), node-negative (LN-) invasive breast cancers (BC) and later also for ER+ and 1-3 LN+BC, provides a low, intermediate or high 10-year risk recurrence score (LRS, IRS or HRS) for BC. Based on the score, the addition of adjuvant chemotherapy (AC) to endocrine therapy is recommended for HRS; no benefit for LRS, and unclear benefits for IRS.

The test has been in use since 2004. Payment for OD was approved by the Centers for Medicare&Medicaid Services in 2006. Patient selection for OD use remains unclear, and data on utilization and impact of the assay in clinical practice across the US are lacking.

The utilization and impact of OD across the US is presented in a retrospective observational study of National Cancer Data Base (NCDB) patients (represents 75% of the US population) from 2010-2012. This time period encompasses the beginning of required recording of molecular assays and the latest data released by NCDB in 4/2015. Demographic and clinical variables of all patients that had OD results were analyzed using frequency statistics, chi-square and logistic regression analysis.

513080 patients had BC; 406525 were ER+. 86409 patients with known OD results were analyzed (23.7% of ER+). Patients age range from 19-90 (mean 58.8, median 59 years); 99.1% were females.

Demographic and clinicopathologic characteristics of OD tested patientsCharacteristicsOD 86409=100%Age 18-403429=4%41-6455313=64%65-90+27667=32%Race White75749=87.7%Black6616=7.7%Other4044=4.6%Comorbidities 073901=85.5%110643=12.3%≥21865=2.2%Median Income Quartiles 2008-2012Missing 634=0.7%$&lt;3800010430=12.1%$38000-4799917346=20.1%$48000-6299923273=26.9%$&gt;6300034726=40.2%US geographic location CT MA ME NH RI VT5404=6.3%NJ NY PA15781=18.3%DC DE FL GA MD NC SC VA WV18984=22%IL IN MI OH WI16542=19.1%AL KY MS TN4704=5.4%IA KS MN MO ND NE SD7256=8.4%AR LA OK TX4342=5%AZ CO ID MT NM NV UT WY4757=5.5%AK CA HI OR WA8639=10%Urban vs ruralMissing 2264=2.6%Urban79642=92.2%Rural4503=5.2%ERMissing 190=0.2%ER+85018=98.4%ER-1181=1.4%ER borderline20=0.0002%Cancer stageUnknown 626=0.7%I58614=67.8%II25907=30%III1134=1.3%IV128=0.2%Tumor size (mm)Missing 723=0.8%1-52825=3.3%6-1017997=20.8%11-5063509=73.5%51-9001355=1.6%LN+Missing 2147=2.4%070165=81.2%110322=12%2-33113=3.6%4-39662=0.8%Histologic gradeUnknown 4178=4.8%G123142=26.8%G244451=51.4%G3&G414638=17%

57.9% of tests followed National Comprehensive Network (NCCN)-defined intermediate risk guidelines (ER+/LN- tumors &gt;1cm), while 15.5% of tests included N1 disease and 25.7% included T1a, T1b and T3 tumors. LRS had 90.1% negative predictive value (NPV) for no AC administration. IRS had 47.4% positive predictive value (PPV) and HRS had 88.9% PPV for AC administration.

OD score and chemotherapy administration ChemotherapyChemotherapyTotalOD scoreNoYes LRS42600=90.1%4014=9.9%46614IRS12740=52.6%11520=47.4%7591HRS840=11.1%6751=88.9%78465

The OD is obtained in almost ¼ of ER+BC patients across the US. Its application across geographic and racial groups is fair. Factors influencing patient selection for OD test and AC administration upon obtaining IRS results require further study.

Citation Format: Orucevic A, Heidel RE, Bell JL. Utilization and impact of oncotype DX 21- gene breast cancer assay in clinical practice across the US: 2010-2012 National cancer data base analysis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-18.