Background There are two types of breast cancer: in situ or invasive. Among invasive, 15% over-express a particular receptor called Human Epidermal growth factor Receptor 2 (HER2). Trastuzumab specifically targets this oncoreceptor. Nevertheless, this molecule has a partially reversible cardiotoxicity in 4.6% to 34% of patients. Monitoring of cardiotoxicity should be implemented according to the European Society of Cardiology (ESC).

Purpose The aim of the study was to assess the adherence to cardiac toxicity monitoring recommended by the ESC in patients treated with trastuzumab.

Material and methods Patients treated with at least two injections of trastuzumab (intravenously or subcutaneously) between 1 January and 1 July 2018, were included. Clinical data were assessed retrospectively from the hospital software patient’s record. Data collected included the demographics characteristics at the start of the treatment, the administration data and the potential risk factors for cardiotoxicity. Parameters used to monitor the occurrence of cardiotoxicity and its management were also assessed and compared to the ESC guidelines and the traztuzumab summary of product characteristics.

Results Among 20 females included, 15 (75%) were followed up according to the recommendations. One (5%) was presenting a discrepancy in the imaging follow-up of left ventricular ejection fraction (LVEF), three (15%) did not have a close follow-up of the LVEF compared to the recommendations and one (5%) had a break in treatment of six cycles before restarting because of the decrease in LVEF. Six of the 20 patients (30%) had a LVEF decrease which required closer monitoring. Among these, three cases of cardiotoxicity with clinical signs were observed. A case of irreversible cardiotoxicity despite beta blocker (BB) management, a reversible case but requiring a temporary interruption of six cycles and treated with BB and angiotensin converting enzyme inhibitor and finally a totally reversible case treated with BB. All three patients received pre-treatment with anthracycline (epirubicin) and had hypertension since initiation of trastuzumab.

Conclusion Seventy-five per cent of patients treated were followed up in accordance with the recommendation. The appearance of cardiotoxicity seems to be favoured by some previous events as mentioned in the literature. Nevertheless, since the number of patients included is small, a larger study should support these results.

References and/or acknowledgements https://ejhp.bmj.com/content/19/2/163.3

https://academic.oup.com/eurheartj/article/37/36/2768/2197413

https://www.ema.europa.eu/documents/product-information/herceptin-epar-product-information_fr.pdf

https://ansm.sante.fr/S-informer/Informations-de-securite-Lettres-aux-professionnels-de-sante/Herceptin-R-trastuzumab-rappel-de-l-importance-des-mesures-de-surveillance-cardiaque-pendant-le-traitement-pour-reduire-la-frequence-et-la-severite-des-dysfonctionnements-ventriculaires-gauches-et-des-insuffisances-cardiaques-congestives-Lettre-aux-professionnels-de-sante

No conflict of interest.