Comparing Oncotype DX Recurrence Score Categories with Immunohistochemically Defined Luminal Subtypes

Abstract

Background: At the 13th St Gallen International Breast Cancer Conference in 2013, a new definition of luminal Alike and luminal B-like breast cancer was proposed, involving the expression of estrogen receptor (ER), progesterone receptor (PgR), and Ki-67. We examined the rate of concordance between the risk groups using the Oncotype DX recurrence score (RS) and the previous and newly proposed luminal subtypes with the standardized Ki-67 assessment. Method: The relationship between a previously and newly proposed, immunohistochemically defined luminal A and B subtype with the Oncotype DX RS of 41 cases of T1-2 N0-1 M0 (ER positive, HER2 negative) breast cancer was assessed. We first classified the patients into the previously defined luminal A and B subtypes, according to the level of Ki-67 as either "low" (<14%) or "high" (≥14%), as assessed by local pathologists. Next, to consider the necessity for standardizing Ki-67 measurement methods, we reexamined Ki-67 with a central review. By introducing PgR positivity (≥20%), we classified these patients to newly proposed luminal subtypes and compared them with the risk groups stratified by Oncotype DX RS. Results: In the previously proposed luminal subtypes, the concordance rate between luminal A and the low RS category was 76.5% according to local pathologists and 90.1% by central review, whereas the rate between luminal B and the intermediate to high RS category was 46.7% and 45.8%, respectively. In newly proposed luminal subtypes, the concordance rate between luminal A and low RS category was 100% and between the luminal B and intermediate to high RS category was 53.6%. Conclusions: Although this study was based on a retrospective chart review of a small sample size, the newly proposed luminal subtypes including

Consensus guidelines for the management of HR-positive HER2/neu negative early breast cancer in India, SAARC region and other LMIC by DELPHI survey method

“…If biomarker testing indicates a low risk for cancer recurrence, chemotherapy can be avoided in such patients. Oncotype DX and CanAssist Breast are known to identify high-risk patients from luminal-A like patients and low-risk patients from luminal-B like patients [ 40 , 61 ].…”

Invasive Ductal Breast Cancer with Osteoclast-Like Giant Cells: A Case Report Based on the Gene Expression Profile for Changes in Management

“…Given the rarity of the histotype, the case was subjected to a second anatomopathological review at another hospital, which confirmed the histopathological characteristics reported. Given that luminal A-like tumors are more likely low-grade and with low RS than luminal B-like tumors [ 41 ], by subjecting this case to Oncotype Dx, we expected to obtain a low RS. We obtained an intermediate RS of 23, which, combined with the patient’s age of 49, suggested a chemotherapy benefit of approximately 6.5%.…”