borderline significancep = 0.057
In the multivariate model, HER2 status (HR = 0.630, p = 0.008), menopausal status (HR = 2.362, p < 0.001), the presence of BRCA1/2 mutations (HR = 3.300, p = 0.01), axillary surgery (HR = 2.091, p = 0.003), adjuvant chemotherapy and radiation therapy (HR = 0.373, p < 0.001 and HR = 2.534, p < 0.001), higher pT and pN stages, and Ki-67 expression exceeding 20% (borderline significance, p = 0.057) remained as significant predictors of OS.