ESR1 and neoplasm: The OS and BCSS benefit with BCS plus RT was observed in the following four subsets: non-blacks group, well-differentiated group, tumor size < 1 cm, and ER(+) group (non-blacks: OS: HR = 0.8441 p = 0.014; BCSS: HR = 0.7967 p = 0.008; well-differentiated: OS: HR = 0.7518 p = 0.002; BCSS: HR = 0.6651 p = 0.001; < 1 cm: OS HR = 0.8179 p = 0.022; BCSS: HR = 0.7940 p = 0.032; ER (+): OS: HR = 0.8095 p = 0.015; BCSS: 0.6950 p < 0.001).