A Retrospective Study of the Impact of 21-Gene Recurrence Score Assay on Treatment Choice in Node Positive Micrometastatic Breast Cancer

Abstract

To assess clinical utility of the 21-gene assay (Oncotype DX® Recurrence Score®), we determined whether women with HER2(−)/ER+ pN1mi breast cancer with low (<18) Recurrence Scores results are given adjuvant chemotherapy in a lower proportion than those with high scores (≥31). This was a multicenter chart review of ≥18 year old women with pN1mi breast cancer, HER2(−)/ER+ tumors, ductal/lobular/mixed histology, with the assay ordered on or after 1 January 2007. One hundred and eighty one patients had a mean age of 60.7 years; 82.9% had ECOG performance status 0; 33.7% had hypertension, 22.7% had osteoporosis, 18.8% had osteoarthritis, and 8.8% had type-2 diabetes. Mean Recurrence Score was 17.8 (range: 0–50). 48.6% had a mastectomy; 55.8% had a lumpectomy. 19.8% of low-risk group patients were recommended chemotherapy vs. 57.9% in the intermediate-risk group and 100% in the high-risk group (p < 0.001). A total of 80.2% of the low-risk group were recommended endocrine therapy alone, while 77.8% of the high-risk group were recommended both endocrine and chemotherapy (p < 0.001). The Oncotype DX Recurrence Score result provides actionable information that can be incorporated into treatment planning for women with HER2(−)/ER+ pN1mi breast cancer. The Recurrence Score result has clinical utility in treatment planning for HER2(−)/ER+ pN1mi breast cancer patients.

Impact of Micrometastatic Axillary Nodes on Survival of Breast Cancer Patients with Tumors ≤2 cm

“…In addition to local therapy, systemic treatments can modify the survival outcomes of patients. Biologic factors including breast cancer subtype and multigene assay score have consistently been associated with treatment decisions and outcomes for patients with pN1mi disease [27, 28]. Our subgroup analyses also presented advantages of chemotherapy in patients with the non‐luminal A‐like subtype and node‐positive disease.…”

Outcomes in Premenopausal Patients with HR+/HER2− Breast Cancer and Lymph Node Micrometastasis Based on the 21-Gene Recurrence Score

“…Another multicenter chart review of patients with estrogen receptor-positive and HER2-negative pN1mi breast cancer found that despite this limited data, clinical practice differed by recurrence score: most patients with low recurrence scores (defined by that study as RS < 18) were recommended endocrine monotherapy (80.2%), while the majority of patients (77.0%) with RS ≥ 31 were recommended combined endocrine and chemotherapy ( P < .001). 12 Because the publication of that study, clinical consensus on pertinent RS cutoffs has evolved, and our study uses updated 21-gene recurrence score cutoffs based on the TAILORx trial to confirm that treatment practices for patients with RS < 26 differ by lymph node status. In our analysis of patients with RS < 26, we found that despite this low-risk stratification by ODX, combined chemo-endocrine therapy was used 2-fold more frequently in patients with pN1mi compared to pN0, yet not as often as in patients with pN1a-c disease.…”

Impact of 21-Gene Recurrence Score on Chemotherapy Decision in Invasive Ductal Carcinoma of Breast with Nodal Micrometastases

“…The 21-gene RS assay is also recommended in patients with N1mi disease. However, limited studies are available to assess whether the 21-gene RS results are useful in guiding decisions regarding chemotherapy beyond standard clinicopathologic characteristics [15]. In light of this, we performed a population-based study to assess the predictive and prognostic value of the 21-gene RS assay on decision for chemotherapy in N1mi patients.…”