ERBB2 and cancer: Accounting for cancer characteristics, comorbidities, polypharmacy, and socio-economic factors, older patients had reduced likelihood of receiving any anti-HER2 therapy compared with patients younger than 55 (RR 0.75, 95% CI 0.66–0.85, p < 0.001, at age 75–84 and RR 0.21, 95% CI 0.11–0.41, p < 0.001, at age 85 +).