In subgroup analysis, the radiotherapy group demonstrated consistently favorable CSS rates compared to the no-radiotherapy group, except for undifferentiated tumor grade (66.7% vs. 40.0%, P = 0.619) and hormone receptor-negative/human epidermal growth factor receptor 2 (HER2)-positive (67.8% vs. 80.3%, P = 0.360) patients. Here, ERBB2 is linked to neoplasm.