MKI67 and neoplasm: Subgroup analysis showed similar treatment effects between the EP and EC-P groups by age, subtype, tumor grade, Ki67 level, lymphovascular invasion, and endocrine therapy, but indicated differential effects in postmenopausal patients (DFS events: 20.1% vs 30.3%; HR, 0.59 [95% CI: 0.38-0.91) and in patients without radiotherapy (DFS events: 14.0% vs 23.6%; HR, 0.55 [95% CI, 0.32-0.93]).