What is the OncoType DX Test?
When I was diagnosed in 2009, a new genomic test had just been announced for early stage breast cancer. In my case, it would save me from the standard of chemotherapy that was to be included as part of my immediate treatment plan. The test was so new in fact, that I had to petition my insurance company to obtain authorization for coverage.
The Oncotype DX Breast Recurrence Score test is a genomic-based, comprehensive, individualized risk assessment test for early-stage invasive breast cancer. Eligible patients are diagnosed with early stage, ER+, HER2- breast cancer with either node-negative or node-positive disease. The test uses RT-PCR to measure the expression of 21 genes: 16 cancer-related genes and five reference genes - in a tumor sample after it has been removed by surgery or biopsy. the benefit from chemotherapy and whether the patient can be treated effectively with hormonal therapy alone.
The landmark TAILORx trial enrolled 10,273 patients from over 1,000 sites who were candidates for adjuvant chemotherapy as per NCCN Guidelines and monitored their 9-year outcomes. The trial investigated the clinical utility of Oncotype DX Breast Recurrence Score test to confidently predict the patient population who will substantially benefit from chemotherapy. Patients with Recurrence Score (RS) results 0-25 showed excellent outcomes when treated with endocrine therapy alone, while patients with RS results 26-100 are known to have significant chemotherapy benefit. TAILORx also showed that standard clinical risk features alone were not sufficient to determine chemotherapy benefit - often leading to overtreatment or undertreatment of patients.