Oncotype DX Testing for Breast Cancer

Technical Details and Methodology

The American College of Medical Genetics and Genomics recommends the use of Oncotype DX, a 21-gene expression profiling test that predicts the likelihood of distant breast cancer recurrence and potential benefit from chemotherapy in patients with hormone receptor-positive, HER2-negative early-stage breast cancer 1
Oncotype DX is a proprietary laboratory-developed test that uses reverse-transcription polymerase chain reaction (RT-PCR) to analyze the expression of 21 genes in formalin-fixed, paraffin-embedded breast cancer tissue, generating a Recurrence Score (RS) on a scale of 0-100, which correlates to a patient-specific risk of distant recurrence 2

Patients with a low Recurrence Score (<18) have a 6.8% risk of distant recurrence at 10 years with endocrine therapy alone, according to the National Comprehensive Cancer Network (NCCN) guidelines 2, 3
The NCCN guidelines also state that patients with an intermediate Recurrence Score (18-30) have a 14.3% risk of distant recurrence at 10 years, and those with a high Recurrence Score (>31) have a 30.5% risk of distant recurrence at 10 years 2

The Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group found adequate evidence for the clinical validity of Oncotype DX in predicting risk of distant metastases in women with hormone receptor-positive, early-stage breast cancer that is either node-negative or node-positive 1, 4
The American Society of Clinical Oncology (ASCO) states that Oncotype DX results have been demonstrated to change treatment decisions regarding chemotherapy in clinical practice 1

The NCCN guidelines recommend that Oncotype DX is most appropriate for patients with stage I or II breast cancer, hormone receptor-positive tumors, HER2-negative status, and lymph node-negative or limited lymph node-positive disease 1, 3

The NCCN guidelines recommend considering Oncotype DX testing to refine risk stratification for adjuvant chemotherapy decisions in appropriate patients, with a strength of evidence of category 2A 3
Economic modeling studies suggest that Oncotype DX may be cost-effective in several healthcare systems, according to the American College of Medical Genetics and Genomics, though these are based on assumptions about clinical utility that require further confirmation 1, 3