Study Finds Discrepant Decision-Making for Use of 21-Gene Assay in Women With Early-Stage Breast Cancer
The largest study to date of the 21-gene recurrence score (RS) assay, Oncotype DX,™ has revealed that many clinicians are using the test and applying results inappropriately. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Breast Cancer recommend adjuvant chemotherapy in patients with node-positive breast cancer. Nevertheless, many clinicians have adopted their interpretation of the inclusion criteria for the ongoing RxPONDER (Rx for Positive Node, Endocrine-Responsive Breast Cancer) trial and are treating patients according to tumor biology, rather than tumor size or stage. The RxPONDER trial looks at low to intermediate RS scores and compares patients treated with hormone therapy alone vs those treated with hormone therapy plus chemotherapy.
Researchers from the University of Colorado Cancer Center found that oncologists are using the RS assay in patients with high-risk disease and, in some cases, forgoing adjuvant chemotherapy as a result. Moreover, they found that clinicians are testing high-risk patients, despite current evidence; that there is nonconcordance with NCCN Guidelines® recommendations; and that racial and socioeconomic factors (ie, type of insurance coverage) affect decisions about assay use.
“The results of well-designed clinical trials often inform clinical practice. As pointed out by Jasem and colleagues, clinicians not infrequently follow their instincts, rather than wait for the data from a trial. This practice may have unintended consequences including recommending adjuvant chemotherapy, or not, inappropriately—denying benefit to some and exposing unnecessary toxicity to others,” said William J. Gradishar MD, of Robert H. Lurie Comprehensive Cancer Center of Northwestern University; Chair of the NCCN Guidelines® panel for Breast Cancer.