CYP19A1 and neoplasm: Patients with tumours expressing only one hormone receptor did not experience any benefit in adapted overall survival when receiving extended aromatase inhibition: the 10-year adapted overall survival was 75.2% (95% CI 68.2–80.8) in the 6-year treatment group and 81.0% (95% CI 74.7–86.0) in the 3-year treatment group (HR 1.33; 95% CI 0.86–2.05) (Supplementary Figs. S1 and S2B).