Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Background: Randomised clinical trials (RCTs) demonstrate that trastuzumab improves survival in patients with human epidermal growth factor 2-positive early breast cancer (HER2 + EBC), but real-world patients and clinical practice often differ from RCTs. We examine real-world treatment patterns and outcomes associated with trastuzumab for HER2 + EBC. Methods: We identified all Australians dispensed trastuzumab for HER2 + EBC between 1/1/2007 and 30/6/2016. We estimated the proportion of patients completing 12 months of treatment (defined as ≥350 days of exposure within 540 days of initiation). We estimated overall survival (OS) and recurrence-free survival (RFS) by using trastuzumab dispensing for metastatic breast cancer as a surrogate for recurrence. Results: Our study included 14,644 patients. Among patients with ≥540 days of follow-up (n = 11,903), 67.4% completed 12 months of trastuzumab. OS rates at 5 and 9 years were 92.7 and 87.9%, and RFS rates at 5 and 9 years were 86.8 and 81.4%, respectively. Patients who completed 12 months of trastuzumab had a 9-year OS rate of 90.2% compared with 86.2% among patients receiving <12 months of therapy (adjusted HR 0.71, 95% CI 0.62–0.81). Conclusions: Real-world HER2 + EBC patients are less likely to complete 12 months of trastuzumab than some clinical trial counterparts but have survival outcomes comparable to those reported in landmark RCTs.

Original publication




Journal article


British Journal of Cancer

Publication Date





904 - 911