[236] How Much Is Oncotype DX Recurrence Score Impacting the Adjuvant Treatment Management of Node-Negative Early-Stage Breast Cancer Patients?

Michaela T Nguyen, Zhengming Chen, Timothy D'Alfonso, Alexander Stessin, Himanshu Nagar, Mary Hayes, Sandra J Shin. Weill Cornell Medical Center, New York, NY; New York Presbyterian, Weill Cornell Medical Center, New York, NY

Background: Oncotype DX (Genomic Health) is a commercially available 21 gene RT-PCR assay that is widely used to determine the risk of distant disease recurrence and the benefit of adjuvant chemotherapy in patients with early-stage breast cancer. We sought to investigate the clinical impact of Oncotype DX testing compared to traditional clinicopathologic features in the planning of adjuvant treatment (chemotherapy) in node-negative, ER/PR positive, Her2neu-negative early-stage breast cancer patients.
Design: A single-center retrospective study (2005-2012) was conducted on 543 patients who had Oncotype DX testing performed as part of their routine clinical care. Age, tumor size, tumor type, tumor grade, lymphovascular invasion, nodal status, ER/PR status, Her2neu status by IHC and FISH, proliferation index (Ki-67), Oncotype DX recurrence score (ODxRS), and treatment were obtained by electronic medical record for each patient. Logistic regression was performed to determine the association between age, tumor size, tumor grade, present of lymphovascular invasion and lymph node micrometastasis, Ki-67 index, and ODxRS; and the utilization of adjuvant chemotherapy in these patients.
Results: 313 of 543 patients were identified to have node-negative, ER/PR positive, Her2neu-negative early-stage invasive breast cancer. Among these 313 patients, 175 (55.9%) had low risk ODxRS, 126 (40%) intermediate risk ODxRS, and 12 (3.8%) had high risk ODxRS. 68 of 313 (21.7%) patients received adjuvant chemotherapy of which 12 of 68 (17.6%) patients had low risk ODxRS, 45 of 68 (65.2%) had intermediate risk ODxRS, and 11 of 68 (11.3%) had high risk ODxRS. The remaining 245 (78.3%) patients did not receive adjuvant chemotherapy of which 163 of 245 (66.5%) had low risk ODxRS, 81 of 245 (33.1%) had intermediate risk ODxRS, and 1 of 245 (0.4%) had high risk ODxRS. A statistically significant association between high risk ODxRS and adjuvant chemotherapy utilization was identified (OR 84.6; 95% CI 24.5, 292; p-value <0.001) and this association was more significant than any association using clinicopathologic parameters.
Conclusions: Our results indicate that when Oncotype DX is performed, high risk ODxRS significantly favored adjuvant chemotherapy utilization more than known clinicopathologic factors in the management of node-negative, ER/PR positive, Her2neu-negative early-stage breast cancer patients.
Category: Breast

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 30, Wednesday Morning


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