Cardiotoxicity monitoring guidelines in patients on anti-HER2 therapy

Introduction 

Anti-HER2 therapies such as Trastuzumab carry warnings for cardiotoxicity, though cardiac assessment and monitoring remains an area of clinical debate. Utility of cardiotoxicity monitoring protocols in light of refined treatment regimens is unknown. The degree to which day-to-day clinical practice is informed by current guidelines is unclear. 

Methods 

A brief survey was designed to audit guideline awareness relating to cardiotoxicity prevalence and monitoring in breast cancer patients treated with HER2-targeted therapy amongst a representative cohort (n=10) of non-consultant hospital doctors (NCHDs) on the breast cancer surgical service in a large tertiary referral centre. 

Results 

Some lack of awareness of current guidelines across grades was evident, which likely reflects a disconnect between the theoretical guidelines and their clinical usefulness, as well as the relatively infrequent prevalence of cardiotoxicity. Although understanding of normal parameters was generally good (80% of NCHDs correctly recognising normal baseline LVEF as >55%), appropriate frequency of monitoring (12 weekly) was underestimated by 90% of this cohort (n=10). All respondents also underestimated the recommended frequency of monitoring in patients with cardiac impairment. Prevalence of cardiotoxicity was overestimated by all respondents. Although 90% of clinicians surveyed could suggest several assessment modalities, MUGA scans were not mentioned, despite being the method suggested in the Irish guidelines. 

Conclusion 

Cardiotoxicity is an infrequent but clinically important adverse event in the treatment of HER2-positive breast cancer patients. This small study suggests the timeliness of reviewing and potentially updating current guidelines to reflect imaging advances, as well as re-examining the criteria for scanning frequency in light of refined treatment protocols.