Abstract PO3-01-13: A study of the impact of the implementation of the Oncotype Dx 21-gene breast-cancer assay during the SARS-CoV-2 pandemic for 1-3 node positive early breast cancer: The Clatterbridge Cancer Centre Experience

Abstract Background: The 21-gene breast cancer (BC) assay (Oncotype Dx) is used to predict chemotherapy benefit in ER+, HER-2- lymph node (LN) negative BC. The RxPONDER trial demonstrated that post-menopausal patients with ER+, HER2- BC with 1-3 LN and a recurrence score (RS) of 25 did not benefit from adjuvant chemotherapy. In response to the SARS-CoV-2 pandemic Oncotype Dx was implemented for ER+, HER2- 1-3 LN+ BC patients in Merseyside, UK (population 2.6 million) This study sought to understand the impact of this measure on clinical practice. Methods: All patients whose tumours were assessed with Oncotype Dx assay between Mar 20 - Nov 22 were identified through the Exact Sciences portal. Menopausal status, tumour characteristics, RS and chemotherapy regimen were recorded. The impact on cancer care was estimated using the number of infusions and clinic visits specified by our institution chemotherapy protocol for node positive disease. The financial impact was calculated using the test list price, estimated costs of adjuvant chemotherapy in the UK (Annals of Oncology, Volume 32, suppl 2 S46). The number of patients predicted to receive chemotherapy pre-oncotype DX was calculated using data from the UK PONDx trial data. Results: A total of 242 patients were tested over the 32 month period. Table 1 summarises the clinico-pathological characteristics including by RS score. The median age was 58.5 and 77.3% (n=187) were post-menopausal. The median tumour size was 25mm and median LNs with macrometastasis was 1. 198 (81.9%) patients had an RS 25. Overall 73 patients (30%) received chemotherapy of which 34 had an RS 25. Pre-menopausal patients were more likely to receive chemotherapy with RS 25 than post-menopausal patients, 47.9% (23/48) vs 7.3% (11/150) respectively. In the absence of Oncotype Dx testing 169 patients would have received adjuvant chemotherapy. Therefore, 96 patients avoided chemotherapy. This equates to 1,620 chemotherapy infusions and 324 clinic attendances. The estimated cost saving was ~£50K. Conclusions: This real-world study demonstrates that the use of Oncotype DX assay for ER+,HER2- 1-3 LN+ early BC spared a significant number of patients chemotherapy during the SARS-CoV-2 pandemic, so avoiding the risk of adverse effects. This also resulted in benefits to the healthcare system with a reduction in scheduled cancer care and achieved financial savings. This, therefore, demonstrates the benefit of using the Oncotype Dx assay. Table 1: Clinico-pathological information Citation Format: Alexandra Johnson, Sonia Bathla, Leena Chagla, Joanne Cliff, Allison Hall, Anita Hargreaves, Clare Hart, Zafar Malik, Chandeena Roshanlall, Raj Sripadam, Carlo Palmieri, Helen Innes. A study of the impact of the implementation of the Oncotype Dx 21-gene breast-cancer assay during the SARS-CoV-2 pandemic for 1-3 node positive early breast cancer: The Clatterbridge Cancer Centre Experience abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-01-13.