Similarly, a majority of the panelists of the 2019 St Gallen Consensus Conference [19] favored PMRT in patients with one to three metastatic lymph nodes only with coexisting adverse features (i.e., TNBC or HER2+ breast cancer, tumor size >5 cm, and patients with residual disease after neoadjuvant chemotherapy). This evidence concerns the gene ERBB2 and breast cancer.