Calculation of St. Gallen International Expert Consensus

RS ranges from 1 to 100; a lower score indicated that the risk of relapse is minimal and the patients have low benefit from chemotherapy. We also set up the kappa coefficient as minimal, weak, moderate, strong, and almost perfect, as shown in ^{Table 1}. 21-gene assay was performed according to NCCN guidelines. It also was confirmed by American Society of Clinical Oncology (ASCO) and St. Gallen International Expert Consensus, which not only provided the relapse risk of within and beyond 5 years, but also predicted the benefits of chemotherapy or endocrine therapy in ER-positive patients with invasive breast cancer.

Kappa agreement setting.

Kappa coefficient is 0.223 (weak), P < 0.001.