ESR1 and neoplasm: In the simple models, year of diagnosis (2005- to end of follow up vs 1977-1989: HR = 0.36, 95% CI = 0.25 to 0.51), age at diagnosis (younger than 35 years vs 45-54 years: HR = 3.11, 95% CI = 2.10 to 4.60; 75 years or older vs 45-54 years: HR = 2.10, 95% CI = 1.55 to 2.85), tumor grade (3 vs 1: HR = 4.55, 95% CI = 3.23 to 6.41), ER status (ER+ vs ER-: HR = 0.65, 95% CI = 0.53 to 0.80), PR status (PR+ vs PR-: HR = 0.55, 95% CI = 0.46 to 0.66), and HER2 status (HER+ vs HER-: HR = 3.87, 95% CI = 2.01 to 7.45) were associated with risk of BCD.