Recurrence score along the continuum of increasing nodal burden in breast cancer.

Abstract

101 Background: The Oncotype Dx (ODX) Recurrence Score (RS) stratifies breast cancer patients (pts) by risk of recurrence and potential benefit of adjuvant chemotherapy. Pts with early stage, estrogen receptor (ER) positive, lymph node-negative breast cancer were included in the initial validation studies. Limited data exists on the application of ODX in node positive pts. We review our experience with RS along the continuum of nodal burden. Methods: A prospective database of pts with breast cancer for whom ODX RS was obtained for treatment planning was reviewed by final surgical pathology. Patients were grouped into four pathologic categories: negative sentinel lymph node [N0(i-)], isolated tumor cells [N0(i+)], micro-metastasis [N1mic] and macro-macrometastasis [N1, 1-3 + nodes]. P values were calculated using the exact Wilcoxon Rank Sum Test. Results: 637 pts were identified in the study period: 521 (81.8%) pts had negative sentinel lymph nodes; 54 (8.5%) pts had isolated tumor cells (N0(i+)); 29 (4.6%) pts had N1mic, and 33 (5.2%) had N1 disease (Table). Median age overall was 58yrs, median invasive tumor size was 1.5cm; 475 (91.2%) had ductal histology. Median RS for the study pts was 17 (range 0-85), and increasing RS had no correlation to increasing nodal burden (p=0.23). Pathologic factors associated with nodal status were lymphovascular invasion (LVI) and histology. The frequency of LVI was higher with increasing nodal burden (p<0.0001). Ductal histology was significantly associated with abnormal nodal findings. (p = 0.002). Age, mitotic rate, grade and degree of ER-positive staining on IHC were not significantly associated with sentinel lymph node status (p > 0.05). Conclusions: Tumor size, histology and LVI were significant predictors of increased nodal burden. However, ODX RS was neither predictive nor reflective of increasing nodal disease. RS is a potentially useful tool in adjuvant systemic treatment decisions in patients with positive lymph nodes but should not impact decisions regarding local-regional therapy. [Table: see text]