Should post-mastectomy radiation be used for node-negative breast cancer patients?

The article comments on the study "Patients Subsets With T1-T2 Node-Negative Breast Cancer at High Locoregional Recurrence Risk After Mastectomy," by P. T. Troung et al. It cites that the study aims to identify combinations of pathologic factors that predict for locoregional recurrence (LRR) rates of ≥20% among patients with small tumors treated with mastectomy. It notes that data about the risk of LRR among patients is critical in knowing which patients may benefit from adjuvant radiation.