Parallel Comparison of 18 Gene Classifiers and Oncotype DX (Nanostring)

With improved diagnosis, breast cancer can now be detected at early stages, thus improving survival rates. However, overtreatment is common; considering that the risk of recurrence is low, patients may suffer from side effects without receiving the full benefits of adjuvant therapies.

To overcome the imprecision of prognosis based on clinicopathologic factors, genomic tests for breast cancer prognosis, such as the Oncotype DX® (ODx), MammaPrint®, and EndoPredict® assay kits, are frequently utilized. These multigene panels were development based on Caucasian populations, and may not suitable to Asian population due to the differences in the incidence and lifestyle of breast cancer patients from different ethic backgrounds. To fiil this gap, an 18-gene classifier (18-GC) based on the gene-expression profiling of Chinese breast cancer patients was developed

In the current study, investigators combined clinical variables and genetic information to generate a clinical-genomic model: RI-DR, a recurrence index for distant recurrence (based on a genomic model and 6 clinical variables: age, tumor size, lymph node status, estrogen receptor status, lymphovascular invasion, tumor grading).

By using tissues that have been tested with ODx, in this study, investigators evaluated the performance of the RI-DR model with that of the ODx assay in the prognosis assessment of a cohort of patients from Taiwan.

Inclusion criteria

• Patients who have performed (Oncotype Dx) genetic testing methods before June 30, 2017.
• Surgery (mastectomy or breast preservation) as the first treatment.
• ER or PR IHC positive
• HER2 negative
• N0-N1 patient
• Available with FFPE tumor tissue

Exclusion criteria

• T3-T4 or N2-N3
• With distant metastasis before surgery
• Preoperative chemotherapy / radiotherapy
• Insufficient FFPE tumor samples