[303] Infiltrating Pleomorphic Lobular Carcinoma: High Oncotype DX Score Augments Its "Aggressive" Reputation

SP Salvatore, JS Estrella, H Rennert, SA Hoda. New York Presbyterian Hospital - Weill Cornell Medical Center, New York, NY

Background: Emerging data indicate that the Pleomorphic Variant of Infiltrating Lobular Carcinoma (PV-ILC) has more aggressive potential, and significantly worse recurrence-free survival than the Classical Variant of Infiltrating Lobular Carcinoma (CV-ILC). PV-ILC and CV-ILC share E-cadherin negativity and a common molecular pathway; however, the biological profile of PV-ILC remains relatively unexplored.
Design: Estrogen receptor (ER)-positive breast carcinoma cases with concurrently obtained Oncotype DX® Recurrence Score (ODX-RS) [a 21-gene commercially available molecular test (Genomic Health, Inc, Redwood City, CA)] were categorized for morphological type (ductal versus lobular, confirmed with E-cadherin immunostain) and conventional Nottingham grade(1-3). ODX-RS and 10-year recurrence rate (RR), both as reported by ODX, from patients with PV-ILC were compared to those with CV-ILC and infiltrating duct carcinoma (IDC) of all 3 grades.
Results: The results of 153 ER-positive cases with concurrent ODX-RS and 10-year RR are tabulated below for PV-ILC and CV-ILC, well differentiated-IDC (WD-IDC), moderately differentiated-IDC (MD-IDC), and poorly differentiated-IDC (PD-IDC).

nRS10-year RRp value
n: number of cases, RS: ODX-RS, RR: Recurrence Risk, *statistically significant

Conclusions: ODX-RS even in ER-positive PV-ILC are significantly higher than in CV-ILC, WD-IDC and MD-IDC; and are statistically similar to those obtained in PD-IDC. Our data further augment the mounting evidence that PV-ILC is an “aggressive” tumor.
Category: Breast

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 27, Wednesday Morning


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