Oncotype DX and Prosigna in breast cancer patients: A comparison study

Abstract

Background: Oncotype Dx® (ODX) is the most used prognostic and predictive assay for ER + breast cancer (BCa) and is categorized into low (< 18), intermediate (18 to 30), or high (≥31) risk of recurrence. Prosigna® is a prognostic signature to estimate distant recurrence-free survival for stage I/II, ER+ cancer in postmenopausal women treated with adjuvant therapy. The goal of the study is to assess the agreement between ODX and Prosigna®. Materials and Methods: 100 previously ODX classified peri and postmenopausal, early-stage (I or II) BCa patients were retrieved and Prosigna assay was performed on archived tumor blocks on a NanoString nCounter® DX Analysis System. Results: ODX assay was assigned as follows: 57% low, 39% intermediate, and 4% high. There were 8% two-step disagreements (high to low or vice versa) between ODX and Prosigna®; and 42% one-step disagreement (low to intermediate or vice versa). 78% were classified by Prosigna as luminal A and 22% as luminal B. The majority of luminal A cases (67/78; 85.9%) had low ROR score whereas ODX classified almost two-thirds (50/78~ 64%) as low RS. An insignificant percentage of luminal B cases (1/22 – 4.5%) were classified as high RS by ODX, and a modest percentage were classified as high ROR by Prosigna (15/22 ~68%). According to our follow up results, recurrence was detected in three cases. In all three cases; Prosigna was a better indicator of recurrence. Conclusions: The agreement between ODX and Prosigna® is low, and this has management implications, especially when chemotherapy is needed.

Keywords

• OncotypeDx
• Prosigna
• Recurrence score
• Breast cancer
• Postmenopausal