Genomic Testing Improves Survival in Ultra-Low-Risk HR+ Breast Cancer
A study in The Oncologist found that Oncotype DX testing improved overall survival in ultra-low-risk HR+ breast cancer patients, with chemotherapy further prolonging survival in high-risk cases. Genomic testing supports personalized treatment decisions.
Risk stratification with a genomic assay had clinically important implications even in ultra-low-risk hormone receptor-positive breast cancer, according to results published in The Oncologist. Investigators from The Ohio State University analyzed data from the United States National Cancer Database, finding that Oncotype DX testing was associated with prolonged overall survival in patients with small, node-negative HR-positive disease.
A total of 102,452 patients underwent Oncotype DX testing, and the genomic assay determined that 11,308 had a recurrence score (RS) of 26 or higher, indicating high risk. Investigators evaluated 11,196 patients with small, node-negative T1mi/a/b HR-positive breast cancer who had a high-risk RS score for overall survival based on receipt of chemotherapy. The patients who did (n=7496) and did not (n=3700) receive chemotherapy had mean ages of 58.1 and 63.2 years (P <.0001); 88.7% and 89.2% were White, 85.2% and 83.2% had a Charlson-Deyo score of 0 (P =.0041), 87.3% and 83.8% had T1b stage (P <.0001), and 78.4% and 88.7% had low or intermediate grade tumor (P <.0001), respectively.
Five-year overall survival was 97.2% in the Oncotype Testing arm and 93.6% compared with those who were not tested. OS was also significantly prolonged with chemotherapy (hazard ratio [HR], 0.61; 95% CI, 0.52-0.72; P <.001). Investigators replicated that result in the propensity score matching analysis (adjusted HR, 0.71; 95% CI, 0.59-0.86; P <.001). In the entire population of patients with node-negative T1mi/a/b HR-positive disease (N=350,911), those who underwent Oncotype DX testing had prolonged OS (HR, 0.58; 95% CI, 0.56-0.60; P <.001). OS was poorer among those with a high RS (HR, 1.22; 95% CI, 1.12-1.34; P <.001).
"These study findings further support the concept of treatment personalization based on tumor biology, with the hope that future stratification tools may aid in selecting those who may benefit from adjuvant chemotherapy," the study investigators concluded. There was no funding listed and study authors disclosed no financial conflicts.