Abstract PS6-38: A comparison of oncotype DX and NHS predict to assess the benefit of adjuvant chemotherapy in patients with early breast cancer

Abstract

INTRODUCTION Early breast cancer (EBC) which is hormone receptor positive, HER2 negative and 0-3 Lymph node positive, defines a Luminal subtype with an excellent outcome and the benefit of adjuvant chemotherapy in this subgroup of patients is increasingly questioned. Gene-expression profile tests have evolved to help stratify risk and to individualise treatment decisions. The 21-gene recurrence-score assay, “Oncotype DX” (ODX) is a genomic test used to quantify the likelihood of distant recurrence (Recurrence Score i.e. RS) and predict chemotherapy benefit. Although it is included in international guidelines as a tool to identify patients who could safely avoid adjuvant chemotherapy, its utility is restricted due to cost in countries with limited resources where it is not covered by insurance. The “NHS Predict” (NHSP) is a freely available online prognostic and predictive test based on cancer registry data. It utilises an algorithm based on clinical parameters and biomarker status to provide an estimate of survival as well as the potential benefit of third generation chemotherapy, hormonal and targeted therapy. The NHSP is based on “Clinical Risk (CR)” while the ODX is based on “Genomic Risk (GR)” assessment. The present study was undertaken to compare the results obtained by ODX with those obtained by NHSP so as to determine the concordance of the two tests and establish the utility of the NHSP in resource-constrained countries. PATIENTS AND METHODS Patients with early ER positive, HER2 negative, 0-3 nodes positive breast cancer, who underwent the ODX assay from January 2010 to March 2020 at a tertiary referral centre were entered into this study. Patients were stratified as per the ODX RS into Low (RS= 0-20 for ≤ 50 years, 0-25 for >50 years) and High (RS= >21 for ≤ 50 years and 26-100 for >50 years) risk for recurrence with absolute chemotherapy benefit (ACB) estimated to be ≤7% and >7% respectively at 9 years.Subsequently, the NHS Predict 2.2 tool (https://breast.predict.nhs.uk/tool ) was used to compute the absolute benefit of third generation chemotherapy for each of these patients. Relevant clinical data i.e. age, menopausal status, tumour size, grade, Ki-67, ER/PR/HER2 status, nodal status and method of detection was entered into the algorithm. The ACB at 10 years, as determined by NHSP, was stratified into Low risk≤ 7% and High risk >7% so as to correspond to the ACB derived from ODX. The results obtained by NHSP were compared to those of the ODX to determine the concordance between the two tests. RESULTS 104 patients were entered into the study. The mean age was 53 years (range 31-76 years), 39.4% were premenopausal and 60.5% post-menopausal. The average tumour size was 19.4mm (range 8-55mm) with 61.53% T1, 36.53% T2 and 1.92% with T3 disease.14.4% were grade 1, 66.3% grade 2, and 19.2% grade 3. 74% were lymph node negative and 14.4%, 9.6% and 0.96% had 1, 2 and 3 positive nodes respectively. On ODX evaluation, low RS was seen in 87 (83.65%), and high RS in 17(16.34%) patients. As per NHSP, 99 (95.19%) patients were classified into low CR and 5 (4.8%) into high CR. There was 82.7% (86/104) concordance between NHSP and ODX with discordance in 18 patients. Of the concordant group, 84 had low CR and GR and 2 had high CR and GR. In the discordant group 15 patients had low CR on NHSP but high GR on ODX and while 3 patients had a high CR on NHSP but ODX showed low GR. CONCLUSIONS In a group of patients with low clinical risk EBC there is high concordance between the NHSP and ODX tests. There is a subgroup of patients with discordant results in whom the ODX may identify patients who could potentially benefit with adjuvant chemotherapy. NHSP can aid decision making regarding adjuvant chemotherapy and identify patients who could potentially avoid chemotherapy in low risk early breast cancer. Citation Format: Vinay Deshmane, Anuja Raniwala. A comparison of oncotype DX and NHS predict to assess the benefit of adjuvant chemotherapy in patients with early breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS6-38.