Abstract P6-17-02: Evaluation of the impact of oncotype DX test results on systemic therapy in breast cancer patients at the BC cancer agency (BCCA)
Authors: Cheng V , Markarian A , de Lemos M , Schaff K 
Published: March 2017

Introduction: The BCCA started funding the Oncotype DX genomic test for node negative, hormone receptor positive and HER2 negative early breast cancer patients in April 2014. Individual requests for the test are reviewed and approved based on predefined BCCA specific eligibility criteria which are, any size grade 3 cancer and any grade 2 cancer over 1cm (later amended to any size) in women 80 and younger, and any grade 1 cancer in women 40 and younger. General consensus is the test result, or Recurrence Score (RS), can be used to guide whether patients should receive endocrine therapy alone (low RS[LRS] &lt;18) or chemoendocrine therapy (high RS[HRS] &gt;30). For patients with intermediate RS (IRS), there is no consensus on whether the benefits of chemotherapy outweigh the risks of potential toxicities.

Objectives: To determine (1) the concordance of RS with treatments given to patients with LRS or HRS, (2) the treatments given to patients with IRS, and (3) the reasons for requesting the genomic test for patients outside the eligibility criteria.

Methods: This was a retrospective, multi-centre analysis of breast cancer patients for whom the genomic test was requested between June 1, 2014 and May 31, 2015. Charts were reviewed to determine the RS and the therapy given following knowledge of the RS. The primary outcome was the concordance rate between LRS and receipt of endocrine therapy only, and HRS and receipt of chemoendocrine therapy. The discordance rate between RS-based recommendations and treatments given, and the type of therapy received by patients with IRS were also explored. Treatments for those with low IRS (18-24) or high IRS (25-30) were examined separately. Finally, we examined the reasons for requesting the genomic test outside eligibility criteria.

Results: 435 requests were received during the study period. 395 requests were approved and test results were not found in 20 cases. Among the 375 RS results, 191 were LRS (51%), 122 were IRS (33%), and 62 were HRS (16%). The concordance rate between RS low and high and given treatments was 96%. Reasons for discordance included: patients with HRS refusing chemotherapy (n=3), patients with LRS receiving chemotherapy (n=3), patients refusing systemic treatment (n=3), and no explanation (n=1). Among the 122 patients with IRS, 81 were low-IRS and 41 were high-IRS. Overall, 27 % of patients with IRS received chemotherapy. Chemotherapy was given in 16 patients (19.7%) with low-IRS and 17 patients (41.4%) with high-IRS. The main reasons for requesting the test for patients outside eligibility criteria were: grade 1 tumors in patients older than 40 years old (n=20), node-positive disease (n=9), and grade 2 tumors less than 11 mm (n=3).

Conclusion: Our results showed that the majority of patients with LRS or HRS were treated in accordance to RS-based recommendations. When treatment differed from RS-based consensus, the main reason was treatment refusal by patients. Only a quarter of patients with IRS received chemotherapy. Ongoing prospective trials will determine the utility of IRS in defining optimal therapy. Patients denied for the test were older and with grade 1 tumors, or with node-positive disease.

Citation Format: Cheng V, Markarian A, de Lemos M, Schaff K. Evaluation of the impact of oncotype DX test results on systemic therapy in breast cancer patients at the BC cancer agency (BCCA) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-17-02.