Use of 21-Gene Recurrence Score Assay in Early-Stage Breast Cancer
The 21-gene recurrence score (RS) assay score was strongly associated with recommendation for adjuvant chemotherapy in patients with early-stage breast cancer, reported Jasem et al in the Journal of Clinical Oncology. Black women and patients treated in community facilities were more likely to receive testing outside the original National Comprehensive Cancer Network (NCCN) Guidelines.
Study Details
The study involved data from 143,032 patients with early breast cancer diagnosed from 2004 to 2012 in the National Cancer Data Base. The 21-gene RS assay is used to predict disease recurrence and benefit of chemotherapy in estrogen receptor–positive, lymph node–negative early-stage disease.
Likelihood of Use
Overall, the RS assay was ordered for 54.0% of patients. The RS assay was the strongest predictor of recommendation for chemotherapy, with adjusted odds ratios (AORs) as high as 12.00 for intermediate scores and 83.07 for high scores. When indicated, assay use was significantly lower for older age (AOR = 0.42), black race (AOR = 0.79), other nonwhite races (AOR = 0.86), and governmental vs private health insurance (AOR = 0.74) and significantly higher for academic centers (AOR = 1.25), larger tumor size (AOR = 1.36), high tumor grade, and pN0(i+) disease (AOR = 1.31). Among those with the assay ordered, 8.1% were outside original NCCN Guidelines. Adjusted odds ratios for use outside guidelines were higher for younger age (1.33), black race (1.3), community facilities (1.49), higher tumor grade (3.12), and male sex (1.42).
Black patients (AOR = 1.51) and patients with a high tumor grade (AOR = 30.76) had significantly higher assay scores. Younger black patients (AOR = 1.33) were more likely to receive chemotherapy despite low assay scores.
The investigators concluded: “The RS assay significantly influences clinicians’ recommendations for chemotherapy in patients with [early-stage breast cancer]. Black patients tended to have higher assay scores, which may reflect use patterns or less favorable tumor biology for estrogen receptor–positive disease. There are significant differences in use and clinical implications of the test on the basis of race, insurance, and type of facility.”
The study was supported by the National Cancer Institute.
Peter Kabos, MD, of the University of Colorado, Aurora, is the corresponding author of the Journal of Clinical Oncology article.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
