Performance of Oncotype Dx test in patients with T1bN0, grade 1, hormone receptor-positive, HER2-negative breast cancer.

Abstract

e12043 Background: NCCN (National comprehensive cancer network) recommends to consider Oncotype DX testing for patients diagnosed with T1bN0 stage 1A breast cancers that are hormone receptor positive and HER-2 negative. This study is a retrospective review of these patients diagnosed at Cone Health Cancer Center between 2012 and 2018 who had Oncotype DX testing. Methods: Patients with T1b hormone receptor positive and HER-2 negative breast cancers, who had Oncotype DX testing performed were queried from tumor registry from 2012 to 2018. Registry provided data on the patients ER/PR and Her 2 neu as well as whether they received chemotherapy. Patient charts were reviewed for grade, Ki 67 and their Oncotype Dx scores. Results: A total of 104 patients with T1b N0 (stage IA ) invasive breast cancers that were ER and PR positive and HER-2 negative between 2012 and 2018 had Oncotype DX test performed. Grade 1 tumors comprised 75 patients. Among these, four patients received adjuvant chemotherapy who had Oncotype scores of 22, 27, 29 and 38. Among patients with Ki 67 ≤ 10% and grade 1, only one patient out of 104 required chemotherapy. Conclusions: This retrospective analysis suggests that 97% of patients with T1b, grade 1, ER/PR positive, HER-2 negative breast cancers had Oncotype scores of less than 25. Hence Oncotype testing may be safely omitted for this group. Grade along with Ki 67 can identify a subset of T1bN0 ER/PR positive and Her 2 negative patients who do not need Oncotype testing.[Table: see text]