Comparing MammaPrint and BluePrintresults between core needle biopsy and surgical resectionbreast cancer specimens

Background : Pre-operative/neoadjuvant treatment utilization in early-stage breast cancer has been increasing,particularly during the COVID-19 pandemic With goals of minimizing potential exposure to SARS-COV-2, as well asresource rationing, physicians are urged to triage breast cancer patients by identifying those that require urgentsurgical care vs those who may delay surgical treatment Accurate risk assessment is an integral component ofthis triaging process, which has recommended that genomic testing on diagnostic core needle biopsy (CNB)samples be used to assist with the identification of patients with low risk tumor biology who may be candidates forsurgical delay MammaPrint (MP), a 70-gene risk of recurrence signature, and BluePrint (BP), an 80-genemolecular subtyping signature, have been routinely used in formalin-fixed paraffin embedded (FFPE) CNB andsurgical resection (SR) samples since MammaPrint obtained FDA clearance for FFPE tissue in 2015 In addition,over 1,500 CNB tumor samples from patients enrolled in prospective neoadjuvant treatment trials (NBRST andISPY-2) have received successful MP & BP testing This study compares the gene expression results between CNBand SR specimens to better elucidate how these tests perform across specimen type Methods: Routine diagnosticsamples submitted to Agendia, Inc (Irvine, CA) between Feb 2017 and May 2020 for MP and BP testing wereprocessed according to standard FFPE microarray procedures MP was used to stratify samples into Ultra Low Risk(UL), Low Risk (LR), and High Risk (HR) BP was used to classify samples into Luminal, HER2, or Basal-type Thisstudy included 13,603 CNB and 25,684 SR specimens MP Index (MPI) distribution on BP defined Luminal-type tumors were compared between CNB and SR samples Comparative “logistics metrics” (average turnaround time[TAT] and success rate) were also assessed between these specimen types Results: Of the 39,287 samplesincluded in this analysis, 35% were CNB and 65% were SR ( Table ) BluePrint Luminal, HER2 and Basal-typedistributions were 86%, 4%, and 10% respectively for CNB samples and 94%, 1%, and 5% respectively for SRsamples Within BP defined Luminal-type tumors, the frequency of UL, LR, and HR results were 18%, 58%, and42% for CNB, and 16%, 60%, and 40% for SR, respectively Overall, MP Index distributions were similar betweensamples tested from CNB vs SR Average TAT between CNB and SR were 4 52 and 4 55 days, respectively Forspecimens that met the minimum tumor % threshold, successful testing rates for CNB and SR were 97 5% and98 4%, respectively Conclusions : MP and BP testing were successfully performed on both CNB and SR samplesin approximately 98% of all eligible specimens with rapid TAT allowing for timely pre-operative decision-making Thefrequency of each MP risk group as well as the distribution pattern of MP Index were nearly identical between CNBand SR specimens, indicating comparable performance regardless of specimen type With no meaningful differencein MPI distribution, TAT or success rate between CNB specimens and SR specimens, pre-operative use of MP+BPgenomic testing is feasible, in alignment with recent COVID-19 pandemic guidelines (Figure Presented)