ESR1 and invasive ductal breast carcinoma: Subgroup analysis demonstrated that the TSR was significantly associated with 5-DFS in invasive ductal carcinoma (HR 0.61; 95% CI 0.38-0.99; P = 0.045), N positive (HR 0.57; 95% CI 0.34-0.97; P = 0.037), ER negative (HR 0.43; 95% CI 0.25-0.74; P = 0.002) and HER2 gene non-amplification groups (HR 0.51; 95% CI 0.28-0.90; P = 0.021).