Recommendations: The Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group found insufficient evidence to recommend for or against the use of Oncotype DX testing to guide chemotherapy treatment decisions in women with hormone receptor-positive, lymph node-negative, or lymph node-positive early breast cancer who are receiving endocrine therapy. This recommendation statement updates a 2009 EGAPP statement on the use of gene expression profiling tests in breast cancer. Evidence of clinical validity for Oncotype DX was confirmed as adequate. With regard to clinical utility, although there was evidence from prospective retrospective studies that the Oncotype DX test predicts benefit from chemotherapy, and there was adequate evidence that the use of Oncotype DX gene expression profiling in clinical practice changes treatment decisions regarding chemotherapy, no direct evidence was found that the use of Oncotype DX testing leads to improved clinical outcomes.
Rationale: In women with early-stage invasive breast cancer, gene expression profiling is increasingly being used as an aid to estimate the likely benefit from chemotherapy treatment. In a previous recommendation statement, the EGAPP Working Group (EWG) found adequate evidence for clinical validity of some gene expression profiling tests in predicting distant disease recurrence in women with early-stage, hormone receptor-positive, lymph-node-negative breast cancer who are treated with tamoxifen, but insufficient evidence that use of these tests for decisions about chemotherapy treatment has clinical utility. The current recommendation statement updates these findings for Oncotype DX and extends them to the population of women with lymph node-positive disease, using evidence from recent systematic reviews and other sources.
Analytic validity: The previous recommendation statement found that evidence was inadequate to enable quantitative determination of the analytic validity of Oncotype DX. Analytic validity was not reconsidered in the updated recommendation statement because there remains no gold-standard test for comparison.
Clinical validity: The EWG found that new evidence published since the original evidence review supports 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.
Clinical utility: No direct evidence was found that use of Oncotype DX tumor gene expression profiling to guide treatment decisions improves clinical outcomes in women with early breast cancer. There is indirect evidence, from prospective retrospective studies on archived tissue samples from randomized controlled trials, that the Oncotype DX test can predict benefit from chemotherapy. Large, prospective, randomized, controlled trials currently in progress may provide evidence of clinical utility.
Contextual issues: Until definitive evidence for clinical utility is available, clinicians must decide on a case-by-case basis whether to offer the test to patients. Although Oncotype DX testing has been reported, on the basis of economic modeling studies, to be cost-effective in several different health-care systems and to save costs in the US health-care setting, studies were based on assumptions regarding the clinical utility of the test that require confirmation by clinical trial results.Genet Med 18 8, 770-779.